Automatic Transmission Shift Position Signal
- While watching shift indicator, shift transmission gear lever to each position. If shift indicator lights up correctly for all positions, turn ignition off.
- Connect ECM test harness between ECM and ECM connectors. Unplug connector "B" from main harness only. DO NOT disconnect from ECM. Turn ignition on. Measure voltage between ECM terminals B7 (positive) and A26 (negative). See Figure .
- If voltage is about 10 volts, reconnect connector "B" to main wiring harness. Go to next step. If voltage is not as specified, substitute a known-good ECM and retest.
- Turn ignition off. Reconnect wire harness to ECM. Place transmission in Neutral. Start engine. Measure voltage between terminals B7 (positive) and A26 (negative).
- If voltage is more than one volt in Neutral, repair open in Light Green wire between ECM terminal B7 and gauge assembly or open in Green wire between gauge assembly and automatic transmission shift position switch. If voltage is less than one volt, go to next step. If voltage is more than one volt in Park, repair open in Green/White wire between gauge assembly and automatic transmission shift position switch. If voltage is less than one volt, go to next step.
- Set transmission selector to Drive position. Measure voltage between terminals B7 (positive) and A26 (negative). If voltage is not about 10 volts, repair short circuit in Light Green wire between ECM terminal B7 and gauge assembly. If voltage is as specified, shift position signal is okay.