Ford Mustang Service Manual: Communications Network (Diagnosis and Testing)

Ford Mustang Service Manual / Electrical Distribution / Module Communications Network / Communications Network (Diagnosis and Testing)

Communications Network (Diagnosis and Testing)

Refer to Wiring Diagrams Cell 14 , Multiplex Communication Network for schematic and connector information.

Special Tool(s)



73 Digital Multimeter or 73 Digital Multimeter or equivalent 105-R0051
Worldwide Diagnostic System Worldwide Diagnostic System (WDS) 418-F224, New Generation STAR (NGS) Tester 418-F052, or equivalent diagnostic tool

Principles of Operation

The vehicle has two module communications networks. The standard corporate protocol (SCP) which is an unshielded twisted pair cable (data bus plus, Circuit 914 [TN/OG] and data bus minus, Circuit 915 [PK/LB]), and the international standards organization (ISO) 9141 network which is a single wire (Circuit 70 [LB/WH]). The diagnostic tool can connect to both networks through the data link connector (DLC). This makes diagnosis and testing of these systems easier by allowing one smart tester to be able to diagnose and control any module on the two networks from one connector. The DLC can be found under the instrument panel between the steering column and the radio.

The ISO 9141 communication network does not permit inter-module communication. When the diagnostic tool communicates to modules on the ISO 9141 communication network, the diagnostic tool must ask for all information; the modules cannot initiate communications.

The SCP network will remain operational even with the severing of one of the bus wires.

Communications will also continue if one of the bus wires is shorted to ground or battery positive voltage (B+) or if some, but not all, termination resistors are lost.

Unlike the SCP communication network, the ISO 9141 communication network will not function if the wire is shorted to chassis ground or battery positive voltage (B+). Also, if one of the modules on the ISO 9141 network loses power or shorts internally, communications to that module will fail.

The powertrain control module (PCM) is on the SCP communication network. The PCM controls the engine for better fuel economy, emissions control, and failure mode detection and storage. Refer to Powertrain Control/Emissions Diagnosis (PC/ED) manual Section 3 for diagnosis and testing of the PCM.

The restraint control module (RCM) is on the ISO 9141 network. The RCM controls the deployment of the air bags based on sensor input.

The generic electronic module (GEM) is on the ISO 9141 network. The GEM module controls a variety of systems including one touch down windows, wipers, perimeter anti-theft, and warning chimes. For additional information, refer to Section.

The anti-lock brake control module communicates over the ISO 9141 communication network when not equipped with traction control and communicates over the SCP communication network when it is equipped with the traction control option. The anti-lock brake control module controls the brake pressure to the four wheels to keep the vehicle under control while braking. For additional information on anti-lock brake control module without traction control, refer to Section. For additional information on anti-lock brake control module with traction control, refer to Section.

The instrument cluster is on the SCP communication network. The instrument cluster displays driver information. The instrument cluster incorporates the PATS control module functions.

Inspection and Verification

1. Verify the customer concern.

2. Visually inspect for obvious signs of electrical damage.

Visual Inspection Chart

Electrical

  • Central junction box (CJB) Fuse 31 (5A)

  • Damaged wiring harness

  • Loose or corroded connections

  • Anti-lock brake control module without traction control (optional)

  • Anti-lock brake control module with traction control (optional)

  • Generic electronic module (GEM)

  • Restraint control module (RCM)

  • Powertrain control module (PCM)

  • Instrument cluster

3. If the concern remains after the inspection, connect diagnostic tool to the data link connector (DLC) located beneath the instrument panel and select the vehicle to be tested from diagnostic tool menu. If diagnostic tool does not communicate with the vehicle:

  • check that the program card is correctly installed.
  • check that the correct version of the program card is installed.
  • check the connections to the vehicle.
  • check the ignition switch position.

If the diagnostic tool still does not communicate with the vehicle, go to Pinpoint Test H.

4. Go to Pinpoint Test PC.

System Precheck

PINPOINT TEST PC: DATA LINK DIAGNOSTICS NETWORK TEST

Test Step Result / Action to Take
PC1 DATA LINK DIAGNOSTICS NETWORK TEST Yes

Test PASSED. RETURN to the Symptom Chart of the section for the module in question.

No

If no response from the diagnostic tool, GO to Pinpoint Test H .

If CKT70=ALL ECUS NO RESP / NOT EQUIP, GO to Pinpoint Test F .

If CKT914 or CKT915=ALL ECUS NO RESP / NOT EQUIP, GO to Pinpoint Test G .

If CKT70, CKT914, or CKT915=SOME ECUS NO RESP/NOT EQUIP, REFER to Symptom Chart.

If the module in question is NO RESPONSE ON CKT914 (BUS+), or NO RESPONSE ON CKT915 (BUS-), REFER to Symptom Chart.

If the module in question is NO RESPONSE/NOT EQUIPPED, REFER to Symptom Chart.
  • Run the Data Link Diagnostics Network Test.
  • Is SYSTEM PASSED obtained?

Symptom Chart

Condition Possible Sources Action
  • The module does not respond to the diagnostic tool - anti-lock brake control module
  • Wire or connection in SCP communication network (with traction control).
  • Wire or connection in ISO 9141 communication network (without traction control).
  • Anti-lock brake control module without traction control (optional).
  • Anti-lock brake control module with traction control (optional).
  • GO to Pinpoint Test A .
  • The module does not respond to the diagnostic tool - generic electronic module (GEM)
  • Wire or connection in ISO 9141 communication network.
  • GEM.
  • GO to Pinpoint Test B
  • The module does not respond to the diagnostic tool - restraint control module (RCM)
  • Wire or connection in ISO 9141 communication network.
  • RCM.
  • GO to Pinpoint Test C .
  • The module does not respond to the diagnostic tool - instrument cluster
  • Wire or connection in SCP communication network
  • Instrument cluster.
  • GO to Pinpoint Test D .
  • The module does not respond to the diagnostic tool - powertrain control module (PCM)
  • Wire or connection in SCP communication network.
  • PCM.
  • GO to Pinpoint Test E
  • No module/network communication - ISO 9141 network
  • Wire or connection in ISO 9141 communication network.
  • ISO 9141 networked modules.
  • GO to Pinpoint Test F .
  • No module/network communication - SCP network
  • Wire or connection in SCP communication network.
  • SCP networked modules
  • GO to Pinpoint Test G .
  • No module/network communication - no power to the diagnostic tool
  • CJB Fuse 31 (5A).
  • DLC pins.
  • Scan tool.
  • Circuitry.
  • GO to Pinpoint Test H .

Pinpoint Tests

CAUTION: Be careful when probing the CJB, battery junction box (BJB) or any connectors. Damage will result to the connector receptacle if the probe or terminal being used is too large.

CAUTION: Electronic modules are sensitive to static electrical charges. If exposed to these charges, damage may result.

NOTE: If DTCs are recorded and the symptom is not present when carrying out the pinpoint tests, an intermittent concern may be the cause. Always check for loose connections and corroded pins.

PINPOINT TEST A: THE MODULE DOES NOT RESPOND TO THE DIAGNOSTIC TOOL - ANTI-LOCK BRAKE CONTROL MODULE

Test Step Result / Action to Take
A1 CHECK THE VEHICLE FOR TRACTION CONTROL Yes

GO to A2 .

No

GO to A9 .
  • Check the vehicle for a traction control disable switch.
  • Is a traction control disable switch present?
A2 CHECK ANTI-LOCK BRAKE CONTROL MODULE C141 FOR DAMAGE Yes

GO to A3 .

No

GO to A6 .
  • Key in OFF position.
  • Disconnect: Anti-Lock Brake Control Module C135.
  • Inspect the anti-lock brake control module C135 for damage; repair as necessary.
  • Connect: Anti-Lock Brake Control Module C135.
  • Connect the diagnostic tool.
  • Key in ON position.
  • Enter the following diagnostic mode on the diagnostic tool: Diagnostic Data Link.
  • Was the result retrieved ABS: NO RESPONSE ON CKT914 (BUS+)?
A3 CHECK FOR OPEN BETWEEN DLC C251 AND ANTILOCK BRAKE CONTROL MODULE C135 - CIRCUIT 914 (TN/OG) Yes

INSTALL a new anti-lock brake control module. REFER to Section. TEST the system for normal operation.

No

GO to A4 .
  • Key in OFF position.
  • Disconnect the diagnostic tool.
  • Disconnect: Anti-Lock Brake Control Module C135.
  • Measure the resistance between anti-lock brake control module C135 Pin 30, Circuit 914 (TN/OG), harness side and DLC C251 Pin 2, Circuit 914 (TN/OG), harness side.


  • Is the resistance less than 5 ohms?
A4 CHECK CIRCUIT 914 (TN/OG) BETWEEN DLC C251 AND IN-LINE C144 FOR OPEN Yes

REPAIR Circuit 914 (TN/OG) between anti-lock brake control module C135 and in-line C144.

For additional information, REFER to Communication Circuit Wiring Repair . TEST the system for normal operation.

No

GO to A5 .
  • Disconnect: In-Line C144.
  • Check in-line C144 for damage; repair as necessary.
  • Measure the resistance between in-line C144 Pin 6, Circuit 914 (TN/OG), harness side and DLC C251 Pin 2, Circuit 914 (TN/OG), harness side.


  • Is the resistance less than 5 ohms?
A5 CHECK CIRCUIT 914 (TN/OG) BETWEEN DLC C251 AND IN-LINE C215 FOR OPEN Yes

REPAIR Circuit 914 (TN/OG) between in-line C144 and in-line C215. For additional information, REFER to Communication Circuit Wiring Repair . TEST the system for normal operation.

No

REPAIR Circuit 914 (TN/OG) between DLC C251 and in-line C215. For additional information, REFER to Communication Circuit Wiring Repair . TEST the system for normal operation.
  • Disconnect: In-Line C215.
  • Check in-line C215 for damage; repair as necessary.
  • Measure the resistance between in-line C215 Pin 10, Circuit 914 (TN/OG), harness side and DLC C251 Pin 2, Circuit 914 (TN/OG), harness side.


  • Is the resistance less than 5 ohms?
A6 CHECK FOR OPEN BETWEEN DLC C251 AND ANTILOCK BRAKE CONTROL MODULE C135 - CIRCUIT 915 (PK/LB) Yes

INSTALL a new anti-lock brake control module. REFER to Section. TEST the system for normal operation.

No

GO to A7 .
  • Key in OFF position.
  • Disconnect the diagnostic tool.
  • Measure the resistance between anti-lock brake control module C135 Pin 29, Circuit 915 (PK/LB), harness side and DLC C251 Pin 10, Circuit 915 (PK/LB), harness side.


  • Is the resistance less than 5 ohms?
A7 CHECK CIRCUIT 915 (PK/LB) BETWEEN DLC C251 AND IN-LINE C144 FOR OPEN Yes

REPAIR Circuit 915 (PK/LB) between anti-lock brake control module C135 and in-line C144.

For additional information, REFER to Communication Circuit Wiring Repair . TEST the system for normal operation.

No

GO to A8 .
  • Disconnect: In-Line C144.
  • Check in-line C144 for damage; repair as necessary.
  • Measure the resistance between in-line C144 Pin 13, Circuit 915 (PK/LB), harness side and DLC C251 Pin 10, Circuit 915 (PK/LB), harness side.


  • Is the resistance less than 5 ohms?
A8 CHECK CIRCUIT 915 (PK/LB) BETWEEN DLC C251 AND IN-LINE C215 FOR OPEN Yes

REPAIR Circuit 915 (PK/LB) between in-line C144 and in-line C215. For additional information, REFER to Communication Circuit Wiring Repair . TEST the system for normal operation.

No

REPAIR Circuit 915 (PK/LB) between DLC C251 and in-line C215. For additional information, REFER to Communication Circuit Wiring Repair . TEST the system for normal operation.
  • Disconnect: In-Line C215.
  • Check in-line C215 for damage; repair as necessary.
  • Measure the resistance between in-line C215 Pin 13, Circuit 915 (PK/LB), harness side and DLC C251 Pin 10, Circuit 915 (PK/LB), harness side


  • Is the resistance less than 5 ohms?
A9 CHECK FOR OPEN BETWEEN THE DLC C251 AND ANTI-LOCK BRAKE CONTROL MODULE C135 - CIRCUIT 70 (LB/WH) Yes

INSTALL a new anti-lock brake control module. REFER to Section. TEST the system for normal operation.

No

GO to A10 .
  • Key in OFF position.
  • Disconnect: Anti-Lock Brake Control Module C135.
  • Inspect anti-lock brake control module C135 for damage, repair as necessary.
  • Measure the resistance between anti-lock brake control module C135 Pin 24, Circuit 70 (LB/WH), harness side and DLC C251 Pin 7, Circuit 70 (LB/WH), harness side.


  • Is the resistance less than 5 ohms?
A10 CHECK FOR OPEN BETWEEN THE DLC C251 AND IN-LINE C140 Yes

REPAIR Circuit 70 (LB/WH) between in-line C140 and antilock brake control module C135.

TEST the system for normal operation.

No

GO to A11 .
  • Disconnect: In-Line C140.
  • Inspect in-line C140 for damage, repair as necessary.
  • Measure the resistance between in-line C140 Pin 7, Circuit 70 (LB/WH), harness side and DLC C251 Pin 7, Circuit 70 (LB/WH), harness side.


  • Is the resistance less than 5 ohms?
A11 CHECK FOR OPEN BETWEEN THE DLC C251 AND IN-LINE C314 Yes

REPAIR Circuit 70 (LB/WH) between in-line C314 and in-line C140. TEST the system for normal operation.

No

REPAIR Circuit 70 (LB/WH) between in-line C314 and DLC C251. TEST the system for normal operation.
  • Disconnect: In-Line C314.
  • Inspect in-line C314 for damage, repair as necessary.
  • Measure the resistance between in-line C314 Pin 1, Circuit 70 (LB/WH), harness side and DLC C257 Pin 7, Circuit 70 (LB/WH), harness side.


  • Is the resistance less than 5 ohms?

PINPOINT TEST B: THE MODULE DOES NOT RESPOND TO THE DIAGNOSTIC TOOL - GENERIC ELECTRONIC MODULE (GEM)

Test Step Result / Action to Take
B1 CHECK FOR OPEN BETWEEN THE DLC C251 AND GEM C201e Yes

INSTALL a new GEM. For additional information, REFER to Section.

TEST the system for normal operation.

No

REPAIR Circuit 70 (LB/WH) between the GEM C201e and DLC C251. TEST the system for normal operation.
  • Key in OFF position.
  • Disconnect: GEM C201e.
  • Inspect GEM C201e for damage, repair as necessary.
  • Measure the resistance between GEM C201e Pin 6, Circuit 70 (LB/WH), harness side and DLC C251 Pin 7, Circuit 70 (LB/WH), harness side.


  • Is the resistance less than 5 ohms?

PINPOINT TEST C: THE MODULE DOES NOT RESPOND TO THE DIAGNOSTIC TOOL - RESTRAINT CONTROL MODULE (RCM)

Test Step Result / Action to Take
C1 CHECK CIRCUIT 70 (LB/WH) FOR OPEN Yes

INSTALL a new RCM.

REFER to Section. TEST the system for normal operation.

No

REPAIR Circuit 70 (LB/WH) between RCM C2041 and DLC C251 .

TEST the system for normal operation.
  • Key in OFF position.
  • Inspect the DLC C251 and diagnostic tool terminal for damage; repair as necessary.
  • Deactivate the air bag system.
  • Disconnect: RCM C2041.
  • Inspect RCM C2041 for damage, repair as necessary.
  • Measure the resistance between DLC C251 Pin 7, Circuit 70 (LB/WH), harness side and RCM C2041 Pin 5, Circuit 70 (LB/WH), harness side.


  • Is the resistance less than 5 ohms?

PINPOINT TEST D: THE MODULE DOES NOT RESPOND TO THE DIAGNOSTIC TOOL - INSTRUMENT CLUSTER

Test Step Result / Action to Take
D1 CHECK INSTRUMENT CLUSTER C220a FOR DAMAGE Yes

GO to D2 .

No

GO to D3 .
  • Key in OFF position.
  • Disconnect: Instrument Cluster C220a.
  • Inspect instrument cluster C220a for damage; repair as necessary.
  • Connect: Instrument Cluster C220a.
  • Connect the diagnostic tool.
  • Key in ON position.
  • Enter the following diagnostic mode on the diagnostic tool: Diagnostic Data Link.
  • Was the result received ICM: NO RESPONSE ON CKT914 (BUS+)?
D2 CHECK FOR OPEN BETWEEN DLC C251 PIN 2 AND INSTRUMENT CLUSTER C220a PIN 1 - CIRCUIT 914 (TN/OG) Yes

INSTALL a new instrument cluster. For additional information, REFER to Section . TEST the system for normal operation.

No

REPAIR Circuit 914 (TN/OG) between instrument cluster C220a and DLC C251. For additional information, REFER to Communication Circuit Wiring Repair . TEST the system for normal operation.

 
  • Key in OFF position.
  • Disconnect the diagnostic tool.
  • Disconnect: Instrument Cluster C220a.
  • Measure the resistance between instrument cluster C220a Pin 1, Circuit 914 (TN/OG), harness side and DLC C251 Pin 2, Circuit 914 (TN/OG), harness side.


  • Is the resistance less than 5 ohms?
D3 CHECK FOR OPEN BETWEEN DLC C251 PIN 10 AND INSTRUMENT CLUSTER C220a PIN 2 - CIRCUIT 915 (PK/LB) Yes

INSTALL a new instrument cluster. For additional information, REFER to Section . TEST the system for normal operation.

No

REPAIR Circuit 915 (PK/LB) between instrument cluster C220a and DLC C251. For additional information, REFER to Communication Circuit Wiring Repair . TEST the system for normal operation.
  • Key in OFF position.
  • Disconnect the diagnostic tool.
  • Measure the resistance between instrument cluster C220a Pin 2, Circuit 915 (PK/LB), harness side and DLC C251 Pin 10, Circuit 915 (PK/LB), harness side.


  • Is the resistance less than 5 ohms?

PINPOINT TEST E: THE MODULE DOES NOT RESPOND TO THE DIAGNOSTIC TOOL - POWERTRAIN CONTROL MODULE (PCM)

Test Step Result / Action to Take
E1 CHECK PCM C175 FOR DAMAGE Yes

GO to E2 .

No

GO to E4 .
  • Key in OFF position.
  • Disconnect: PCM C175.
  • Inspect PCM C175 for damage; repair as necessary.
  • Connect: PCM C175.
  • Connect the diagnostic tool.
  • Key in ON position.
  • Enter the following diagnostic mode on the diagnostic tool: Diagnostic Data Link.
  • Was the result received PCM: NO RESPONSE ON CKT914 (BUS+)?
E2 CHECK FOR OPEN BETWEEN DLC C251 PIN 2 AND PCM C175 PIN 16 - CIRCUIT 914 (TN/OG) Yes

REFER to Powertrain Control/Emissions Diagnosis (PC/ED) manual Section 3. TEST the system for normal operation.

No

GO to E3 .
  • Key in OFF position.
  • Disconnect the diagnostic tool.
  • Disconnect: PCM C175.
  • Measure the resistance between PCM C175 Pin 16, Circuit 914 (TN/OG), harness side and DLC C251 Pin 2, Circuit 914 (TN/OG), harness side.


  • Is the resistance less than 5 ohms?
E3 CHECK CIRCUIT 914 (TN/OG) BETWEEN DLC C251 AND IN-LINE C215 FOR OPEN Yes

REPAIR Circuit 914 (TN/OG) between PCM C175 and in-line C215. For additional information, REFER to Communication Circuit Wiring Repair . TEST the system for normal operation.

No

REPAIR Circuit 914 (TN/OG) between DLC C251 and in-line C215. For additional information, REFER to Communication Circuit Wiring Repair . TEST the system for normal operation.
  • Disconnect: In-Line C215.
  • Check in-line C215 for damage; repair as necessary.
  • Measure the resistance between in-line C215 Pin 10, Circuit 914 (TN/OG), harness side and DLC C251 Pin 2, Circuit 914 (TN/OG), harness side.


  • Is the resistance less than 5 ohms?
E4 CHECK FOR OPEN BETWEEN DLC C251 PIN 10 AND PCM C175 PIN 15 - CIRCUIT 915 (PK/LB) Yes

REFER to Powertrain Control/Emissions Diagnosis (PC/ED) manual Section 3. TEST the system for normal operation.

No

GO to E5 .
  • Key in OFF position.
  • Disconnect the diagnostic tool.
  • Measure the resistance between PCM C175 Pin 15, Circuit 915 (PK/LB), harness side and DLC C251 Pin 10, Circuit 915 (PK/LB), harness side.


  • Is the resistance less than 5 ohms?
E5 CHECK CIRCUIT 915 (PK/LB) BETWEEN DLC C251 AND IN-LINE C215 FOR OPEN Yes

REPAIR Circuit 915 (PK/LB) between PCM C175 and in-line C215. For additional information, REFER to Communication Circuit Wiring Repair . TEST the system for normal operation.

No

REPAIR Circuit 915 (PK/LB) between DLC C251 and in-line C215. For additional information, REFER to Communication Circuit Wiring Repair . TEST the system for normal operation.
  • Disconnect: In-Line C215.
  • Check in-line C215 for damage; repair as necessary.
  • Measure the resistance between in-line C215 Pin 13, Circuit 915 (PK/LB), harness side and DLC C251 Pin 10, Circuit 915 (PK/LB), harness side.


  • Is the resistance less than 5 ohms?

PINPOINT TEST F: NO MODULE/NETWORK COMMUNICATION - ISO 9141 COMMUNICATION NETWORK

Test Step Result / Action to Take
F1 CHECK CIRCUIT 70 (LB/WH) FOR OPEN Yes

GO to F2 .

No

REPAIR Circuit 70 (LB/WH) between the GEM C201e and DLC C251. TEST the system for normal operation.
  • Key in OFF position.
  • Inspect the DLC C251 Pin 7, Circuit 70 (LB/WH) for damage, repair as necessary.
  • Disconnect: GEM C201e.
  • Measure the resistance between GEM C201e Pin 6, Circuit 70 (LB/WH), harness side and DLC C251 Pin 7, Circuit 70 (LB/WH), harness side.


  • Is the resistance less than 5 ohms?
F2 CHECK FOR SHORT TO GROUND AND POWER AT DLC C251 - GEM C201e DISCONNECTED Yes

CONNECT the GEM module C201e. GO to F3 .

No

INSTALL a new GEM. For additional information, REFER to Section. TEST the system for normal operation.
  • Key in ON position.
  • Measure the voltage between DLC C251 Pin 7, Circuit 70 (LB/WH), harness side and C251 Pin 4, Circuit 1205 (BK); and between DLC C251 Pin 7, Circuit 70 (LB/WH), harness side and C251 Pin 16, Circuit 1047 (LG/RD), harness side.


  • Is the voltage indicated in either measurement zero volts?
F3 CHECK FOR SHORT TO GROUND AND POWER AT DLC C251 - IN-LINE C314 DISCONNECTED Yes

GO to F4 .

No

GO to F5 .
  • Key in OFF position.
  • Disconnect: In-Line C314.
  • Key in ON position.
  • Measure the voltage between DLC C251 Pin 7, Circuit 70 (LB/WH), harness side and C251 Pin 4, Circuit 1205 (BK); and between DLC C251 Pin 7, Circuit 70 (LB/WH), harness side and C251 Pin 16, Circuit 1047 (LG/RD), harness side.


  • Is the voltage indicated in either measurement zero volts?
F4 CHECK FOR SHORT TO GROUND AND POWER AT DLC C251 - RCM C2041 DISCONNECTED Yes

REPAIR Circuit 70 (LB/WH) between DLC C251, GEM C201e, RCM C2041, and inline C314. TEST the system for normal operation.

No

INSTALL a new RCM. REFER to Section. TEST the system for normal operation
  • Key in OFF position.
  • Deactivate the air bag system; REFER to Section.
  • Disconnect: RCM C2041.
  • Key in ON position.
  • Measure the voltage between DLC C251 Pin 7, Circuit 70 (LB/WH), harness side and C251 Pin 4, Circuit 1205 (BK); and between DLC C251 Pin 7, Circuit 70 (LB/WH), harness side and C251 Pin 16, Circuit 1047 (LG/RD), harness side.


  • Is the voltage indicated in either measurement zero volts?
F5 CHECK FOR THE ANTI-LOCK BRAKE CONTROL MODULE Yes

GO to F6 .

No

GO to F7 .
  • Key in OFF position.
  • Connect: In-Line C3141.
  • Check the vehicle for any version of the anti-lock brake control module.
  • Is the vehicle equipped with any version of the antilock brake control module (with or without traction control)?
F6 CHECK FOR SHORT TO GROUND AND POWER AT DLC C251 - ANTI-LOCK BRAKE CONTROL MODULE C135 DISCONNECTED Yes

GO to F7 .

No

INSTALL a new anti-lock brake control module. For additional information on the anti-lock brake control module without traction control, REFER to Section. For additional information on the anti-lock brake control module with traction control, REFER to Section. TEST the system for normal operation.
  • Disconnect: Anti-Lock Brake Control Module C135.
  • Key in ON position.
  • Measure the voltage between DLC C251 Pin 7, Circuit 70 (LB/WH), harness side and C251 Pin 4, Circuit 1205 (BK); and between DLC C251 Pin 7, Circuit 70 (LB/WH), harness side and C251 Pin 16, Circuit 1047 (LG/RD), harness side.


  • Is the voltage indicated in either measurement zero volts?
F7 CHECK FOR SHORT TO GROUND AND POWER AT DLC C251 - IN-LINE C140 DISCONNECTED Yes

REPAIR Circuit 70 (LB/WH) between in-line C314 and inline C140. TEST the system for normal operation.

No

REPAIR Circuit 70 (LB/WH) between in-line C140 and the anti-lock brake control module C135. TEST the system for normal operation.
  • Key in OFF position.
  • Disconnect: In-Line C140.
  • Key in ON position.
  • Measure the voltage between DLC C251 Pin 7, Circuit 70 (LB/WH), harness side and C251 Pin 4, Circuit 1205 (BK); and between DLC C251 Pin 7, Circuit 70 (LB/WH), harness side and C251 Pin 16, Circuit 1047 (LG/RD), harness side.


  • Is the voltage indicated in either measurement zero volts?

PINPOINT TEST G: NO MODULE/NETWORK COMMUNICATION - SCP NETWORK

Test Step Result / Action to Take
G1 CHECK DIAGNOSTIC TOOL PINS FOR DAMAGE Yes

GO to G2 .

No

REPAIR the diagnostic tool terminals. TEST the system for normal operation.
  • Inspect diagnostic tool pins for damage.


  • Are the diagnostic tool pins OK?
G2 CHECK DLC C251 PINS 2 AND 10 FOR DAMAGE Yes

GO to G3 .

No

REPAIR the DLC C251. TEST the system for normal operation.
  • Key in OFF position.
  • Inspect the DLC C251 pins for damage.


  • Are the pins OK?
G3 CHECK THE VEHICLE FOR THE ANTI-LOCK BRAKE CONTROL MODULE Yes

GO to G4 .

No

GO to G7 .
  • Check the vehicle for any version of the anti-lock brake control module.
  • Is the vehicle equipped with any version of the antilock brake control module (with or without traction control)?
G4 CHECK CIRCUIT 914 (TN/OG) AND CIRCUIT 915 (PK/LB) FOR OPEN - ANTI-LOCK BRAKE CONTROL MODULE C135 DISCONNECTED Yes

GO to G5 .

No

REPAIR the circuit(s) in question between in-line C215 and DLC C251. For additional information, REFER to Communication Circuit Wiring Repair . TEST the system for normal operation.
  • Disconnect: Anti-Lock Brake Control Module C135.
  • Measure the resistance between anti-lock brake control module C135 Pin 30, Circuit 914 (TN/OG), harness side and DLC C251 Pin 2, Circuit 914 (TN/OG), harness side.


  • Measure the resistance between anti-lock brake control module C135 Pin 29, Circuit 915 (PK/LB), harness side and DLC C251 Pin 10, Circuit 915 (PK/LB), harness side.


  • Are the resistances less than 5 ohms?
G5 CHECK CIRCUIT 914 (TN/OG) AND CIRCUIT 915 (PK/LB) FOR THE SOURCE OF THE CONCERN - ANTILOCK BRAKE CONTROL MODULE C135 DISCONNECTED Yes

GO to G6 .

No

INSTALL a new anti-lock brake control module. For additional information on the anti-lock brake control module without traction control, REFER to Section. For additional information on the anti-lock brake control module with traction control, REFER to Section.

TEST the system for normal operation.
  • Key in ON position.
  • Measure the voltage between DLC C251 Pin 2, Circuit 914 (TN/OG), harness side and C251 Pin 4, Circuit 1205 (BK); and between DLC C251 Pin 2, Circuit 914 (TN/OG), harness side and C251 Pin 16, Circuit 1047 (LG/RD), harness side.


  • Measure the voltage between DLC C251 Pin 10, Circuit 915 (PK/LB), harness side and C251 Pin 4, Circuit 1205 (BK); and between DLC C251 Pin 10, Circuit 915 (PK/LB), harness side and C251 Pin 16, Circuit 1047 (LG/RD), harness side.


  • Is the voltage zero volts for any measurement?
G6 CHECK CIRCUIT 914 (TN/OG) AND CIRCUIT 915 (PK/LB) FOR THE SOURCE OF THE CONCERN - IN-LINE C144 DISCONNECTED Yes

GO to G8 .

No

REPAIR the circuit(s) in question between in-line C144 and the anti-lock brake control module C135. REFER to Communication Circuit Wiring Repair . TEST the system for normal operation
  • Key in OFF position.
  • Disconnect: In-Line C144.
  • Key in ON position.
  • Measure the voltage between DLC C251 Pin 2, Circuit 914 (TN/OG), harness side and C251 Pin 4, Circuit 1205 (BK); and between DLC C251 Pin 2, Circuit 914 (TN/OG), harness side and C251 Pin 16, Circuit 1047 (LG/RD), harness side.


  • Measure the voltage between DLC C251 Pin 10, Circuit 915 (PK/LB), harness side and C251 Pin 4, Circuit 1205 (BK); and between DLC C251 Pin 10, Circuit 915 (PK/LB), harness side and C251 Pin 16, Circuit 1047 (LG/RD), harness side.


  • Is the voltage zero volts for any measurement?
G7 CHECK CIRCUIT 914 (TN/OG) AND CIRCUIT 915 (PK/LB) FOR OPEN - PCM C175 DISCONNECTED Yes

GO to G8 .

No

REPAIR the circuit(s) in question between in-line C215 and DLC C251. For additional information, REFER to Communication Circuit Wiring Repair . TEST the system for normal operation.
  • Disconnect: PCM C175.
  • Measure the resistance between PCM C175 Pin 16, Circuit 914 (TN/OG), harness side and DLC C251 Pin 2, Circuit 914 (TN/OG), harness side.


  • Measure the resistance between PCM C175 Pin 15, Circuit 915 (PK/LB), harness side and DLC C251 Pin 10, Circuit 915 (PK/LB), harness side.


  • Are the resistances less than 5 ohms?
G8 CHECK CIRCUIT 914 (TN/OG) AND CIRCUIT 915 (PK/LB) FOR THE SOURCE OF THE CONCERN - PCM C175 DISCONNECTED Yes

GO to G9 .

No

REFER to the Powertrain Control/Emissions Diagnosis (PC/ED) manual Section 3 for diagnosis and testing.
  • Key in OFF position.
  • Disconnect: PCM C175.
  • Key in ON position.
  • Measure the voltage between DLC C251 Pin 2, Circuit 914 (TN/OG), harness side and C251 Pin 4, Circuit 1205 (BK); and between DLC C251 Pin 2, Circuit 914 (TN/OG), harness side and C251 Pin 16, Circuit 1047 (LG/RD), harness side.


  • Measure the voltage between DLC C251 Pin 10, Circuit 915 (PK/LB), harness side and C251 Pin 4, Circuit 1205 (BK); and between DLC C251 Pin 10, Circuit 915 (PK/LB), harness side and C251 Pin 16, Circuit 1047 (LG/RD), harness side.


  • Is the voltage zero volts for any measurement?
G9 CHECK CIRCUIT 914 (TN/OG) AND CIRCUIT 915 (PK/LB) FOR THE SOURCE OF THE CONCERN - IN-LINE C215 DISCONNECTED Yes

GO to G10 .

No

REPAIR the circuit(s) in question between in-line C215, in -line C144 (if equipped with the antilock brake control module), and the PCM C175. For additional information, REFER to Communication Circuit Wiring Repair . TEST the system for normal operation.
  • Key in OFF position.
  • Disconnect: In-Line C215.
  • Key in ON position.
  • Measure the voltage between DLC C251 Pin 2, Circuit 914 (TN/OG), harness side and C251 Pin 4, Circuit 1205 (BK); and between DLC C251 Pin 2, Circuit 914 (TN/OG), harness side and C251 Pin 16, Circuit 1047 (LG/RD), harness side


  • Measure the voltage between DLC C251 Pin 10, Circuit 915 (PK/LB), harness side and C251 Pin 4, Circuit 1205 (BK); and between DLC C251 Pin 10, Circuit 915 (PK/LB), harness side and C251 Pin 16, Circuit 1047 (LG/RD), harness side.


  • Is the voltage zero volts for any measurement?
G10 CHECK CIRCUIT 914 (TN/OG) AND CIRCUIT 915 (PK/LB) FOR THE SOURCE OF THE CONCERN - INSTRUMENT CLUSTER C220a DISCONNECTED Yes

REPAIR the circuit(s) in question between in-line C215, DLC C251, and the instrument cluster C220a. For additional information, REFER to Communication Circuit Wiring Repair . TEST the system for normal operation.

No

INSTALL a new instrument cluster. For additional information, REFER to Section. TEST the system for normal operation.
  • Key in OFF position.
  • Disconnect: Instrument Cluster C220a.
  • Key in ON position.
  • Measure the voltage between DLC C251 Pin 2, Circuit 914 (TN/OG), harness side and C251 Pin 4, Circuit 1205 (BK); and between DLC C251 Pin 2, Circuit 914 (TN/OG), harness side and C251 Pin 16, Circuit 1047 (LG/RD), harness side.


  • Measure the voltage between DLC C251 Pin 10, Circuit 915 (PK/LB), harness side and C251 Pin 4, Circuit 1205 (BK); and between DLC C251 Pin 10, Circuit 915 (PK/LB), harness side and C251 Pin 16, Circuit 1047 (LG/RD), harness side.


  • Is the voltage zero volts for any measurement?

PINPOINT TEST H: NO MODULE / NETWORK COMMUNICATION - NO POWER TO THE DIAGNOSTIC TOOL

Test Step Result / Action to Take
H1 CHECK DIAGNOSTIC TOOL PINS FOR DAMAGE Yes

GO to H2 .

No

REPAIR diagnostic tool pins. TEST the system for normal operation.
  • Inspect diagnostic tool pins.


  • Are the pins OK?
H2 CHECK DLC C251 FOR DAMAGE Yes

GO to H3 .

No

REPAIR DLC C251.

TEST the system for normal operation.
  • Key in OFF position.
  • Inspect the DLC C251 pins for damage.


  • Are the pins OK?
H3 CHECK VOLTAGE TO DLC C251 PIN 16 - CIRCUIT 1047 (LG/RD) Yes

GO to H4 .

No

REPAIR Circuit 1047 (LG/RD).

TEST the system for normal operation.
  • Measure the voltage between DLC C251 Pin 16, Circuit 1047 (LG/RD), harness side and ground.


  • Is the voltage greater than 10 volts?
H4 CHECK THE DLC GROUND - CIRCUIT 1205 (BK) AND CIRCUIT 651 (BK/YE) Yes

CHECK diagnostic tool. TEST the system for normal operation.

No

REPAIR the circuit in question. TEST the system for normal operation.
  • Measure the resistance between DLC C251 Pin 4, Circuit 1205 (BK), harness side and ground; and between DLC C251 Pin 5, Circuit 651 (BK/YE), harness side and ground.


  • Is the resistance less than 5 ohms?
Module Communications Network
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Principles of Operation
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Other materials:

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