Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Diagnostic Fault Information
Circuit | Short to Ground | Open or High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Signal | 1 | 1 | 1 | -- |
Ground | -- | 1 | -- | -- |
1. Overdrive Indicator Does not Change States | ||||
Circuit Description
With the ignition switch in the ON position, voltage is applied through the 10 A 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.
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics
Description and Operation
Transmission General Description
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Ignition ON, observe the scan tool Overdrive Switch parameter while pressing and releasing the overdrive switch. The reading should change between ON and OFF.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the overdrive switch.
- Test for less than 5 ohms between the ground circuit terminal 4 and ground.
- Ignition ON, verify the scan tool Overdrive Switch parameter is ON.
- Install a 3A fused jumper wire between the signal circuit terminal 2 and the ground circuit terminal 4. Verify the scan tool overdrive Switch parameter is OFF.
- If all circuits test normal, test or replace the overdrive switch.
| ⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
| ⇒ | If not the specified value, test the signal circuit terminal 2 for a short to ground. If the circuit tests normal, replace the PCM. |
| ⇒ | If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the PCM |
Component Testing
- Ignition OFF, disconnect the harness connector at the overdrive switch.
- Test for infinite resistance between the signal terminal 2 and the ground terminal 4 with the switch in the open position.
- Test for less than 5 ohms between the signal terminal 2 and the ground terminal 4 with the switch in the closed position.
| ⇒ | If not the specified value, replace the overdrive switch. |
| ⇒ | If all circuits test normal, replace the overdrive switch. |
Repair Instructions
| • | Control Module References for PCM replacement, setup, and programming |
