DTC 35 - Discriminating Sensor Open Or Short To Ground

Every time ignition switch is turned to ON position, SDM performs a series of self tests to check for internal malfunctions. If no internal faults are detected, SDM measures voltages in ignition 1, 36 VLR (back-up power supply), and deployment loop circuits. If all of these circuit voltages are within pre-defined parameters, SDM will measure resistance of inflator modules. Next phase of self diagnostics is Continuous Monitoring. During this phase, SDM supplies reference voltage to B6 terminal and measures voltage signal return from forward discriminating sensor at B5 terminal. SDM will set code 35 if signal return voltage drops below a pre-determined limit for about 1/2 second. If this fault occurs intermittently, most probable causes are a poor connection at forward discriminating sensor or SDM, or a damaged SIR wiring harness.

1. Measures resistance of forward discriminating sensor.
2. Checks continuity of Reference Voltage circuit.
3. Checks continuity of Sensor Signal circuit.
4. Checks for a short circuit in Reference Voltage circuit.
5. Checks for a short circuit in Sensor Signal circuit.

Fig 1: DTC 35 - Discriminating Sensor Open Or Short To Ground

Courtesy of GENERAL MOTORS CORP.