Ford Mustang (1999-2004) Service Manual: Pinpoint Test O: DTC B1870 - Air Bag Indicator Shorted to Battery

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 ondemand self test.

GO to O2 .

No

This is an intermittent fault.

The fault condition is not present at this time. GO to O4 .

• 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 B1870 retrieved during the on-demand self test?

INSTALL a new RCM. GO to O5 .

No

GO to O3 .

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.
• Key in ON position.
• Is the air bag indicator illuminated?

REPAIR the instrument cluster.

GO to O5 .

No

REPAIR the circuit. GO to O5 .

• Key in OFF position.
• Disconnect: RCM C2041.
• Disconnect: Instrument Cluster C220a.
• Key in ON position.
• Measure the voltage between RCM C2041 pin 20, circuit 608 (BK/YE), harness side and ground.

• Is the voltage less than 0.2 volt?

CHECK for causes of intermittent short to battery 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 O5 .

No

GO to O5 .

• Refer to the continuous DTCs recorded during Step O1.
• Was the continuous DTC retrieved during Step O1 an intermittent fault?

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 O1.
• Were any continuous DTCs retrieved during Step O1?