With Hard DTCs/ Lamp Fault Codes

DIAGNOSING CUSTOMER CONCERNS WITH HARD DTCs

Most air bag SRS diagnostic procedures will require the use of the deactivation and reactivation procedures.

The deactivation procedure requires installation of air bag simulators on the vehicle harness. Two simulator are required for each frontal air bag and one for each safety belt retractor pretensioner or side airbag. Connecting simulators at the air bag and pretensioner connectors allows diagnostic tests to be done without the risk of air bag deployment or pretensioner activation.

The simulator for the driver air bag are installed on the air bag side of the clockspring connectors to the driver air bag. The passenger air bag connector, the two side air bag and pretensioner connectors must be accessed to attach simulators to the vehicle harness.

Air bag simulators are required to carry out diagnosis and testing of the SRS. The simulator is a 2.5 ohm resistor used to simulate air bag module connections to the system. It is unacceptable to short circuit the air bag module connections with a zero ohm jumper wire. If a zero ohm jumper wire is used to short circuit the air bag module connections, a lamp fault code (LFC) will be displayed.

The reactivation procedure requires the removal of any simulators installed and the reinstallation of all air bag modules removed and pretensioner reconnected.