Diagnostic Instructions
Air Bag and Safety Belt Pretensioner Supplemental Restraint System (SRS)
Diagnostic Instructions
The symptom chart can be used to help locate SRS concerns if no DTCs are retrieved and the listed symptoms are observed. Whether or not the listed symptoms are observed, always carry out the following:
1. Retrieve all DTCs stored in the RCM memory and OCSM memory. Refer to Retrieve/Clear Continuous DTCs.
2. Run the on-demand Self Test to determine what DTCs are currently being sensed by the RCM and OCSM.
3. If on-demand DTCs are different than CMDTCs, always repair the on-demand DTCs first.
A DTC can indicate several concerns. The DTCs are to assist in system diagnosis and are not to be considered definitive. Always refer to the pinpoint test corresponding to the DTC to determine where the concern lies and to repair the concern correctly.
Self Test/On-Demand
The on-demand Self Test option is used to verify that no electrical concerns exist with the SRS. Upon entering the self-test, the RCM/OCSM will make an electrical check of each electrical component in the system. If a concern is detected, a DTC is displayed on the scan tool with a brief description of the DTC. The self-test should always be run after any repair to verify that the repair was successful.
Self Test/Continuous Memory and Clear DTCs
During vehicle operation, the RCM and OCSM will detect and store both intermittent and hard failure DTCs in non-volatile memory. The DTC strategy employed by the RCM incorporates a time-out scheme for determining when a concern exists in the system. This requires a concern to exist for up to one minute in the system before the RCM will detect it. For the RCM to determine that a concern no longer exists, the concern must be absent for up to one minute. The actual detection time-outs vary with each DTC. DTCs can be retrieved with a scan tool using the Self Test option. All DTCs stored in the RCM and OCSM will be displayed on the scan tool along with a brief description of the DTC. If no DTCs are present, the scan tool will display a SYSTEM PASSED message. This option can also be used to clear DTCs from the RCM and OCSM memory, as long as the concern no longer exists.
Once 75 hours of operation have been recorded by the RCM since the concern was last detected, all RCM CMDTCs will be automatically removed from memory.
Once 128 ignition cycles have been recorded by the OCSM since the concern was last detected, all OCSM continuous memory DTCs will be automatically removed from memory.
DataLogger PID/Data
The DataLogger PID/Data option allows the scan tool operator to read the state of several PIDs to aid in diagnosing the system. PIDs are real time measurements of parameters, such as voltages and resistances, calculated by the RCM sent to the scan tool for display. Many of the PIDs supported by the modules are calculated periodically and are, therefore, not true real time readings.
To retrieve PIDs, follow these steps:
1. Connect the scan tool to the DLC.
2. Turn the ignition to the ON position.
3. Follow the manufacturer's instructions for the scan tool being used.
4. Select DataLogger.
5. Select RCM or OCSM.
Active Commands
Instrument Cluster (IC) module
These commands allow the technician to verify the operation of IC module components and subsystems.
Occupant Classification Sensor (OCS) System Reset
The Occupant Classification Sensor (OCS) System Reset active command sets the zero set point or rezeros the OCS system. Refer to Occupant Classification Sensor (OCS) System Reset Programming and Relearning.