Ford Mustang (1999-2004) Service Manual: Pinpoint Test N: DTC B1869 - Air Bag Indicator Inoperative

Normal Operation

The air bag indicator is designed to illuminate for 6 (+/-2) seconds when the ignition switch is turned to the RUN position. This initial 6 seconds of illumination is considered normal operation and is called proveout of the air bag indicator. The air bag indicator is then used to warn the driver that there is a fault in the air bag supplemental restraint system (SRS).

The restraints control module (RCM) monitors the air bag indicator for open and short to ground conditions. If the RCM detects an open or short to ground condition on the air bag indicator circuit, it will store a diagnostic trouble code (DTC) B1869 in memory.

If the RCM detects an air bag indicator failure in addition to another SRS failure, the RCM will send a signal to the generic electronic module (GEM) to produce five sets of five tone bursts.

Possible Causes

An air bag indicator inoperative condition can be caused by:

  • a damaged wiring on circuit 608 (BK/YE).
  • a damaged or burned out air bag indicator.
  • worn or damaged instrument cluster.
  • an RCM internal concern.

PINPOINT TEST N: DTC B1869 - AIR BAG INDICATOR INOPERATIVE

Test Step Result / Action to Take
N1 CHECK FOR A HARD OR INTERMITTENT DTC Yes

This is a hard fault.

The fault condition is still present. This fault cannot be cleared until it is corrected and the DTC is no longer retrieved during the on-demand self test. GO to N2 .

No

This is an intermittent fault.

The fault conditions not present at this time. GO to N5 .

  • Key in OFF position.
  • Connect the diagnostic tool. Scan Tool
  • Key in ON position.
  • Enter the following diagnostic mode on the diagnostic tool: Retrieve/Clear Continuous DTCs.
  • Retrieve and record any continuous DTCs for use later in this pinpoint test.
  • Enter the following diagnostic mode on the diagnostic tool: On- Demand Self Test.
  • Was DTC B1869 retrieved during the on-demand self test?
N2 CHECK THE RCM Yes

INSTALL a new RCM. GO to N6 .

No

GO to N3 .

WARNING: If the supplemental restraint system (SRS) is being serviced, the system must be deactivated and restraint system diagnostic tools must be installed. Refer to Air Bag Supplemental Restraint System (SRS) in this section.

The air bag restraint system diagnostic tools must be removed and the air bag modules reconnected when the system is reactivated to avoid non-deployment in a collision, resulting in possible personal injury.

NOTE: Diagnostics or repairs are not to be performed on a seat equipped with a seat side air bag with the seat in the vehicle. Prior to attempting to diagnose or repair a seat concern when equipped with a seat side air bag, the seat must be removed from the vehicle and the restraint system diagnostic tools must be installed in the seat side air bag electrical connectors. The restraint system diagnostic tools must be removed prior to operating the vehicle over the road.

NOTE: After diagnosing or repairing an SRS, the restraint system diagnostic tools must be removed before operating the vehicle over the road.

NOTE: After diagnosing or repairing a seat system, the restraint system diagnostic tools must be removed before operating the vehicle over the road.

NOTE: The SRS must be fully operational and free of faults before releasing the vehicle to the customer.

  • Key in OFF position.
  • Deactivate the system. Refer to Air Bag Supplemental Restraint System (SRS) in the Diagnosis and Testing portion of this section.
  • Key in OFF position.
  • Disconnect: RCM C2041.
  • Measure the resistance between RCM C2041 pin 20, component side and a known good chassis ground.

  • Is the resistance less than 10 ohms?
N3 CHECK CIRCUIT 608 (BK/YE) FOR A SHORT TO GROUND Yes

REPAIR the circuit. GO to N6 .

No

GO to N4 .

  • Key in OFF position.
  • Disconnect: Instrument Cluster C220a.
  • Measure the resistance to ground at instrument cluster C220a pin 12, circuit 608 (BK/YE).

  • Is the resistance less than 100 ohms?
N4 CHECK CIRCUIT 608 (BK/YE) FOR AN OPEN Yes

REPAIR the circuit. GO to N6 .

No

REPAIR the instrument cluster.

GO to N6 .

  • Disconnect: Instrument Cluster C220a.
  • Measure the resistance between RCM C2041 pin 20, circuit 608 (BK/YE), harness side and instrument cluster C220a pin 12, circuit 608 (BK/YE), harness side.

  • Is the resistance greater than 10 ohms?
N5 CHECK FOR AN INTERMITTENT FAULT Yes

CHECK for causes of intermittent short to ground or open on circuit 608 (BK/YE). Attempt to recreate the hard fault by flexing the wire harness and cycling the ignition key frequently.

REPAIR any intermittent concerns found.

GO to N6 .

No

GO to N6 .

  • Refer to the continuous DTCs recorded during Step N1.
  • Was the continuous DTC retrieved during Step N1 an intermittent fault?
N6 CHECK FOR ADDITIONAL DTCs Yes

Do not clear any DTCs until all DTCs have been resolved. GO to the Restraints Control Module (RCM) Diagnostic Trouble Code (DTC) Priority Table in this section for pinpoint test direction.

No

RECONNECT the system.

REACTIVATE the system. PROVE OUT the system.

REFER to Air Bag Supplemental Restraint System (SRS) in this section. CLEAR all DTCs.

  • Refer to the continuous DTCs recorded during Step N1.
  • Were any continuous DTCs retrieved during Step N1?
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