SIR Diagnostic System Check

SIR Diagnostic System Check:

DESCRIPTION:

When the ignition switch is first turned "ON," system voltage is applied through the fuse #14 to the DERM at the "IGNITION 1" input and through fuse #1 to the DERM at the "SIR Indicator Low" and "SIR Indicator High" inputs. The DERM responds by blinking the "INFLATABLE RESTRAINT" indicator 7 to 9 times.

When the engine is being cranked system voltage is applied to the DERM at the "CRANK" input. The DERM grounds the lamp circuit until system voltage is removed from the "CRANK" input. This results in a steady "INFLATABLE RESTRAINT" indicator during cranking. After cranking the DERM will again blink the "INFLATABLE RESTRAINT" indicator 7 to 9 times.

NOTES ON FAULT TREE:

1. The "INFLATABLE RESTRAINT" indicator should blink 7 to 9 times as the ignition is just turned on.

2. As the engine is "Cranked" the "INFLATABLE RESTRAINT" indicator should remain on steady. If the indicator does not respond use Chart D to diagnose the malfunction.

3. The "INFLATABLE RESTRAINT" indicator has completed the "Bulb Check" and remains on indicating a current code has been detected.

4. The "INFLATABLE RESTRAINT" indicator has completed the "Bulb Check" and goes out, indicating no current codes exist.

5. Record all codes (both History and Current) onto the repair order.

6. If there are no codes (History or Current) record this fact onto the repair order. No further diagnosis is required.

7. If the Driver Information Center indicates that no SIR data is being received from the DERM, then the Data Link will require diagnosis.

8. Codes are displayed (History or Current). The order that the codes are diagnosed is very important. Refer to the recommended charts.