R025

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

During 'Initiator Circuit Resistance' test the DERM grounds the 'DRIVER'S SENSE LOW', terminal 'B8', for 50 milliseconds and measures voltage at 'DRIVER'S SENSE LOW' and 'PASSENGER'S SENSE LOW'. The DERM then grounds 'PASSENGER'S SENSE LOW', terminal 'B?' for 50 milliseconds, and again measures the voltage at 'DRIVER'S SENSE LOW' and 'PASSENGER'S SENSE LOW'. For a properly operating circuit, the voltage measurements during each of these tests will be below 3 volts. When the voltages measured at both 'DRIVER'S SENSE LOW' and 'PASSENGER'S SENSE LOW' are above 3 volts during both tests, Code R025 is set indicating a short to voltage in the initiator circuit.

TEST CONDITION(S)

Tested each ignition cycle during the 'Initiator Circuit Resistance' tests and '10 Minute Loop' test if:

1. No faults detected during 'Turn-On';

2. No faults are detected during 'Continuous Monitoring' for 1 second;

3. No 'CRANK' signal present at DERM;

4. Ignition 1 voltage greater than 7.25 volts at DERM.

FAILURE CONDITION(S)

Voltage at the 'DRIVER'S SENSE LOW', terminal 'B8', and 'PASSENGER'S SENSE LOW', terminal 'B?', is greater than 3 volts.

ACTION TAKEN

1. DERM turns on the 'INFLATABLE RESTRAINT' indicator.

2. 'SERVICE SUPPLEMENTAL INFLATABLE RESTRAINT' message is displayed on DIC.

NOTES ON FAULT TREE

1. This test determines whether the fault is occurring in the steering column circuitry.

2. This test determines whether the fault is occurring in the Passenger's Inflator Module circuitry.

3. Checks for a short to voltage on 'DRIVER'S SENSE HIGH' CKT 347.

4. Checks for a short to voltage on 'DRIVER'S SENSE LOW' CKT 348.

5. Checks for a short to voltage on 'PASSENGER'S SENSE HIGH' CKT 1403.

6. Checks for a short to voltage on 'PASSENGER'S SENSE LOW' CKT 1404.

7. Check for a short to voltage on CKT 349 or a faulty DERM.

8. Determining between which two Discriminating Sensor, CKT 349 is shorted to voltage.