C: Trans. Control Sw. & Indicator Lamp Not Operating Properly

Pinpoint Test C: Transmission Control Switch And Indicator Lamp Not Operating Properly

C1 Check Transmission Control Switch Signal
- Ignition switch in OFF position
- Disconnect instrument interface module.
- Measure resistance of Circuit 91S (BK/GN), Pin 3, to ground while pressing and releasing transmission control switch.

Does Circuit 91S (BK/GN) have 5 ohms or less resistance to ground with TCS pressed and 10,000 ohms or more with TCS released?

Yes
Go to C5.
No
Go to C2.

C2 TCS Signal Shorted
- Disconnect gearshift lever unit connector.
- Measure resistance of Circuit 91S (BK/GN), Pin 7, to ground.

Is resistance to ground 10,000 ohms or more?

Yes
Go to C3.
No
Service short to ground of Circuit 91S (BK/GN). Restore vehicle. Retest system.

C3 Check Continuity Of Circuit 91S (BK/GN)
- Disconnect gearshift lever unit connector.
- Measure resistance of Circuit 91S (BK/GN) between Pin 7 of gearshift lever unit connector and Pin 3 of instrument interface module connector.

Does Circuit 91S (BK/GN) have less than 5 ohms resistance between gearshift lever unit and instrument interface module?

Yes
Go to C4.
No
Service Circuit 91S (BK/GN) for open. Restore vehicle. Retest system.

C4 Check TCS Ground Circuit
- Measure resistance of Pin 8, Circuit 91S (BK/GN) of gearshift lever unit connector to ground.

Is resistance less than 5 ohms?

Yes
Service transmission control switch. Restore vehicle. Retest system.
No
Service open in Circuit 91S (BK/GN). Restore vehicle. Retest system.

C5 Check Voltage On Circuit 8 (W/BL)
- Turn ignition switch to RUN.
- Measure voltage between Circuit 8 (W/BL), Pin 16 or instrument interface module and ground.

Is battery voltage present?

Yes
Go to C11.
No
Go to C6.

C6 Check Fuse 30
- Remove Fuse 30 (7.5A).
- Inspect Fuse 30 (7.5A) in fuse junction panel.

Is fuse open?

Yes
Go to C7�.
No
Go to C8.

C7 Check Circuit 14 (P) For Short To Ground
- Remove Fuse 30 (7.5A).
- Disconnect instrument cluster connector C2.
- Measure resistance of Circuit 14 (P) between Pin C2-5 on the instrument cluster connector and ground.

Is resistance less than 10,000 ohms?

Yes
Service short to ground, Circuit 14 (P). Restore vehicle. Retest system.
No
Go to C8.

C8 Check Circuit 14 (P) For Open
- Remove Fuse 30 (7.5A).
- Measure resistance of Circuit 14 (P) from Fuse 30 to Pin C2-5 of instrument cluster connector.

Is resistance 5 ohms or less?

Yes
Go to C9
No
Service open Circuit 14 (P) between Fuse 30 and instrument cluster connector. Restore vehicle. Retest system.

C9 Check Circuit 8 (W/BL)
- Ignition switch OFF.
- Disconnect instrument interface module connector.
- Measure resistance of Circuit 8 (W/BL) between Pin C2-9 of instrument cluster connector and Pin 16 of instrument interface module connector.

Is resistance less than 5 ohms?

Yes
Go to C10.
No
Service open Circuit 8 (W/BL). Restore vehicle. Retest system.

C10 Check Indicator Lamp Bulb
- Remove overdrive indicator lamp bulb.
- Check continuity between bulb contacts.

Is bulb filament continuous?

Yes
Service open instrument cluster printed circuit.
No
Replace indicator lamp bulb.

C11 Check Interface Module Output
- Ignition switch OFF.
- Disconnect Powertrain Control Module (PCM) harness connector.
- Connect Rotunda EEC-IV 60-Pin Breakout Box 007-00033 or equivalent to harness.
- Measure resistance of Circuit 8 (W/BK) between Pin 41 of breakout box and Pin 6 of interface module connector.
- Measure resistance between Pin 41 of breakout box and ground.

Is resistance between Pin 41 of breakout box and Pin 6 of interface module connector less than 5 ohms and is resistance between Pin 41 of breakout box and ground greater than 10,000 ohms?

Yes
Replace instrument interface module. Restore vehicle. Retest system.
No
Service Circuit 8 (W/BK). Restore vehicle. Retest system.