TB7 - Check Output Driver Signal

NOTE: When entering this test step with a symptom or a Self-Test Pass code, first disconnect Powertrain Control Module (PCM). Inspect for damaged or pushed out pins, loose wires, etc. Service as necessary.

- Key "OFF".

- Breakout box installed, PCM disconnected.

- Key "ON", engine "OFF".

- For 4x4 Low circuit:

- Switch disconnected.

- Measure voltage between test pin 12 (multiport fuel injection vehicles) or test pin 42 (sequential fuel injection vehicles) and PWR GND at the breakout box (Digital Volt/Ohm Meter (DVOM) negative probe).

NOTE: Sequential fuel injection vehicles may be easily identified by their use of a Mass Air Flow (MAF) sensor while multiport fuel injection vehicles use a Manifold Absolute Pressure (MAP) sensor.

- For Transmission Control Indicator Lamp (TCIL) circuit:

- Measure voltage between test pin 32 and PWR GND at the breakout box (DVOM negative probe).

- Are both voltage readings at least 2.0 volts?

Yes -- Go to TB8. TB8 - Check Continuity of Control Switch Harness

No -- Inspect for damaged indicator bulb (4x4 Low LED or TCIL) or damaged fuse in fuse panel. If OK, service open circuit. Remove breakout box. Reconnect all components. Rerun quick test. Quick Test Appendix (Detailed Testing Instructions)