GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2007 🢒 Vibe - FWD 🢒 Transmission/Transaxle 🢒 Automatic Transmission - MU4 🢒 Overdrive Off Indicator Inoperative

Circuit Description

With the ignition switch in the ON position, voltage is applied through the 10A Gage Fuse to the OD/OFF indicator light. Whenever the overdrive switch, located on the shifter, is released to the off position, system voltage is applied through the closed contacts of the overdrive switch to ground. When this occurs, the OD/OFF indicator light in the instrument cluster will light and the powertrain control module (PCM) will simultaneously receive a low voltage signal at the O/D On/Off input. With a low voltage input, the PCM will disable the overdrive function. Whenever the overdrive switch is depressed to the on position, the overdrive switch opens. When this occurs, the O/D/OFF Indicator light in the instrument cluster will go out and the PCM will simultaneously receive a high voltage signal at the O/D On/Off input. With a high voltage input, the PCM will enable the overdrive function and the transaxle is permitted to shift into overdrive when appropriate.

Diagnostic Aids

Inspect for the following conditions:

    • Open GAGE Fuse
    • Poor connections at any in line harness connectors
    • Loose ground connections

An intermittent may be caused by the following conditions:

    • A poor connection
    • Rubbed through wire insulation

Inspect the wiring. If any wiring repairs are necessary, refer to Wiring Repairs .

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. The Powertrain OBD System Check prompts the technician to complete some basic checks and store the freeze frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.

  2. This step checks the O/D OFF indicator light by jumping the switch to ground.

    3.

  3. This step checks the ground circuit and the Overdrive switch.

    4.

  4. This step checks for an open L-GN wire or an open indicator bulb.

Step

Action

Yes

No

Schematic Reference: Automatic Transmission Controls Schematics

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Backprobe the Overdrive switch connector with a fused jumper wire from cavity 2 to ground.
  2. Turn the ignition switch ON.

Does the O/D OFF indicator light?

Go to Step 3

Go to Step 6

3

Backprobe the Overdrive switch connector with a test lamp from cavity 4 to B+.

Does the test lamp light?

Go to Step 5

Go to Step 4

4

Backprobe the instrument cluster connector cavity 13 with a fused jumper to cavity 4 on the switch.

Does the O/D OFF indicator light?

Go to Step 7

Go to Step 8

5

Replace the overdrive switch.

Is the action complete?

Go to Step 9

--

6

Inspect for an open in GN/BK wire between the overdrive switch harness connector and the powertrain control module (PCM).

Is the action complete?

Go to Step 9

--

7

Inspect for an open in L-GN wire between the instrument cluster and the PCM or in GN/BK wire between the PCM and the overdrive switch.

Is the action complete?

Go to Step 9

--

8
  1. Inspect the instrument cluster printed circuit for cracks or poor connections.
  2. If OK, replace O/D OFF indicator bulb.

Is the action complete?

Go to Step 9

--

9
  1. Turn the ignition switch to LOCK.
  2. Reconnect all disconnected connectors.
  3. Turn the ignition switch to the ON position.
  4. Press and release the Overdrive switch while observing the O/D OFF indicator.

Does the O/D OFF indicator light toggle from on to off?

System OK

Go to Step 1