Normal Operation

Safing sensor output - battery feed/return open circuit.

Normal Operation

The diagnostic module measures the voltage on diagnostic module pins 2-5 and 2-6 the voltage varies with the vehicle charge level as shown in the table below:

The diagnostic module also measures the voltage at pin 1-7 (battery input). Using the battery input voltage, the system can predict the expected voltage level on pins 2-5 and 2-6. If the voltage on pins 2-5 or 2-6 is higher or lower than expected, a fault code 24 will be declared.

Possible Causes

• Open circuit or high resistance in the wiring harness or safing sensor.
• Intermittent battery voltage on pin 1-7
• The resistance of the pin 2-5 to 2-6 circuit to ground. This circuit should be open to ground at all times.

Fault Analysis

WARNING: Read and adhere to all warnings and safety procedures at the start of this section when working on the airbag system.

1. Disarm the airbag system and fit airbag simulators (6.4.21.4).
2. Probe the battery input voltage terminal 1-7. Start the engine and monitor the charge voltage level using a digital multimeter. Run the engine at idle speed and look for any instability in the voltage level. Run the engine at a constant medium speed and then at a constant high speed and repeat the observation for voltage instability.

If the voltage levels are stable, go to step 3.

If instability of the voltage level is observed, Investigate and rectify the problem in the charging circuit.

3. Switch off the ignition. Disconnect the diagnostic module and check for 0Ω continuity from pins 2-5 to 2-6.

If no resistance is detected, go to step 4.

If any resistance is detected between pins 2-5 and 2-6, service the wiring or safing sensor to achieve 0Ω continuity.

4. Measure the resistance to ground from pins 2-5 and 2-6.

If no short circuit is detected, replace the diagnostic monitor. Rearm the airbags (6.4.21.4).

If a short to ground is detected, service the wiring or safing sensor as necessary. Rearm the airbags (6.4.21.4).