Test Notes

Normal Operation
Battery voltage is provided at diagnostic monitor pin 15 (Circuit 611, W/O) at all times. However, voltage at pin 15 can be as high as 19 volts (as provided by the backup power supply) when the ignition switch is in the ON position and the backup power supply in the diagnostic monitor is charged up. Circuit 612 (P/O) is connected to Circuit 611 (W/O) inside the safing sensor. Therefore, the voltage at pin 23 (Circuit 612, P/O) should be the same as the voltage at pin 15 at all times. The diagnostic monitor compares the voltage available at pins 15 and 23. If the voltage at pin 23 is low, the diagnostic monitor will flash out code 23 to indicate an open between these two circuits.

Possible Causes
Low voltage at pin 23 can be caused by:
1. An open circuit in the wiring harness in either Circuit 611 (W/O) or 612 (P/O).
2. An open circuit inside the safing sensor across the W/O and P/O wires.