Chart A1 - History Code Diagnosis: Description
When ignition is first turned on, system voltage is applied through fuse No. 6 to REDUNDANT INDICATOR IGNITION 1 input and INFLATABLE RESTRAINT indicator light, which is connected to SIR INDICATOR output. Fuse No. 7 also applies system voltage to IGNITION 1 inputs. DERM responds by flashing INFLATABLE RESTRAINT indicator 7-9 times.
When engine is cranked, system voltage is applied to DERM at CRANK input. DERM grounds light circuit until system voltage is removed from CRANK input. This results in a steady INFLATABLE RESTRAINT indicator during cranking. After cranking, DERM again flashes INFLATABLE RESTRAINT indicator 7-9 times.
NOTE:
Test numbers refer to test numbers on diagnostic chart. For circuit number identification, see WIRING DIAGRAMS.
WARNING:
To avoid air bag deployment while troubleshooting the SIR system, only use test equipment specified in diagnostic charts. Under no circumstances should battery powered test equipment or test light be used. Carefully follow all instructions.
- Checks dual pole arming sensor for a loose connection, which may cause a history code to set.
- Checks for an intermittent open and poor connections in PASS SENSE LOW and DRIVER SENSE LOW circuits, between DERM and either passenger inflator module or steering column connectors.
- Checks for an intermittent short between PASS SENSE HIGH and DRIVER SENSE HIGH circuits.
- Checks for an intermittent short between PASS SENSE HIGH circuit and either DRIVER SENSE LOW or PASS SENSE LOW circuit. Also checks passenger inflator module connector for a loose connection, which may cause shorting bar to set a history code.
- Checks passenger inflator module connector for poor connections at both PASS SENSE HIGH and PASS SENSE LOW circuit terminals.
- Checks passenger compartment discriminating sensor connector for poor connection at DRIVER SENSE LOW circuit terminal.
- Checks dual pole arming sensor for low resistance. Also checks for an intermittent short between initiator circuits and either 36VLR or SOURCE SENSE circuits.