Diagnostic Trouble Codes
Caution: In order to avoid deploying the air bag when troubleshooting the SIR
system, use only the equipment specified in this manual and the instructions
given in this manual. Failure to use the specified equipment as instructed
could cause air bag deployment, personal injury to you or someone else,
or unnecessary SIR system repairs.
The SIR Diagnostic System Check must always be the starting
point of any SIR system diagnosis. The SIR Diagnostic System Check checks
for proper AIR BAG warning lamp operation and checks for SIR Diagnostic
Trouble Codes (DTC) using the scan tool. The following describes the difference
between current and history DTCs:
| • | Current DTCs - Malfunctions that are presently being detected.
Random Access Memory (RAM) stores the current DTCs. Turning the ignition
switch to the OFF position erases current DTCs. The presence of a current
DTC will cause the inflatable restraint Sensing and Diagnostic Module (SDM)
to turn ON the AIR BAG warning lamp. |
| • | History DTCs - All malfunctions detected since last clearing
of history memory. Electrically Erasable Programmable Read Only Memory (EEPROM)
stores the history DTCs. A scan tool clear codes command will erase history
DTCs. |
Some DTCs are latched and can not be cleared. Latched DTCs will require
replacement of the SDM after proper diagnostics.
Use of Special Tools
You should be familiar with the tools in this service category listed
under the heading Special Tools. You should know how to measure voltage and
resistance. Diagnosis requires proper use of the following tools:
| • | The J 38826
SIR Deployment Harness |
| • | The J 38715-A
SIR Driver/Passenger Load Tool |
| • | The J 35616
Connector Test Adaptor Kit |
| • | The J 42113
SIR Shorting Bar Tool |
