Transmission Mode Switch: Testing and Inspection

A/T Shift Position Signal Test

This signal informs the ECU when the transmission is in Neutral or Park positions.

1. Turn ignition switch On, place shifter in each gear position, and observe shift position indicator light. Light should illuminate. If light does not illuminate, check shift position indicator. If light illuminates, proceed to next step.
2. Turn ignition switch Off, then connect system checker harness between ECU and wire harness connector. Disconnect ``B'' connector from main wire harness only, not from ECU.
3. Measure voltage between terminals B7 (+) and A18 (-), then between terminals B9 (+) and A18 (-) of system checker harness. Voltage should be approximately 5 volts. If voltage is as specified, proceed to next step. If voltage is not as specified, substitute a good ECU and recheck voltage. If voltage is now as specified, replace ECU.
4. Reconnect ``B'' connector to main wire harness, position shifter in Neutral, then measure voltage between terminals B7 (+) and A18 (-). There should be no voltage. If voltage is as specified (0 volts), proceed to next step. If voltage is measured, repair open in light green wire between ECU and combination meter or repair open in green wire between combination meter and shift position indicator switch.
5. Position shifter in Park, then measure voltage between terminals B7 (+) and A18 (-). There should be no voltage. If voltage is as specified (0 volts), A/T shift position signal is OK. If voltage is detected, repair open in green/white wire between combination meter and shift position indicator switch.