Backup Lamps Malfunction Automatic Transmission
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/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Backup Lamp Switch Signal | 1 | 1 | 1 | -- |
Backup Lamp - Left Control | B2545 00 | B2545 00 | 1 | -- |
Backup Lamp - Right Control | B3880 00 | B3880 00 | 1 | -- |
Left Rear Stop/Turn Lamp Ground | -- | 1 | -- | -- |
Park/Neutral Position Switch Ground | -- | 1 | -- | -- |
Right Rear Stop/Turn Lamp Ground | -- | 1 | -- | -- |
1. Backup Lamps Malfunction | ||||
Circuit/System Description
The park/neutral position switch receives voltage from the underhood electrical center (UEC) via the backup lamp switch signal circuit. When the transmission is placed in the REVERSE position, the park/neutral position switch closes providing a ground path for the backup lamp switch signal circuit. The UEC responds to the flow of voltage by sending a serial data message to the rear electrical center (REC) requesting the backup lamps be illuminated. The REC applies battery voltage to the backup lamps control circuit illuminating the backup lamps. Once the driver moves the gear selector out of the REVERSE position, a message is sent by the UEC via serial data requesting the REC to remove battery voltage from the backup lamps control circuit. The backup lamps are permanently grounded at G403.
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Exterior Lighting Systems Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Ignition ON, observe the scan tool Reverse Gear Switch parameter while operating the gear selector in and out of the reverse position. The parameter should change between Active and Inactive as the gear selector is operated.
- With a scan tool, command the Reverse Light Test ON and OFF. The backup lamps should turn ON and OFF when commanded.
| ⇒ | If the parameter does not change as the gear selector is operated, refer to Park/Neutral Position Switch Malfunction. |
| ⇒ | If the backup lamps do not illuminate when commanded, refer to Backup Lamps Malfunction. |
Circuit/System Testing
Park/Neutral Position Switch Malfunction
- Ignition OFF, disconnect the harness connector at the park/neutral position switch.
- Ignition OFF, exterior lamps OFF, test for less than 5 ohms between the ground circuit terminal 9 and ground.
- Ignition ON, verify the scan tool Reverse Gear Switch parameter is Inactive.
- Install a 3A fused jumper wire between the signal circuit terminal 7 and ground. Verify the scan tool Reverse Gear Switch parameter is Active.
- If all circuits test normal, replace the park/neutral position 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 7 for a short to ground. If the circuit tests normal, replace the UEC. |
| ⇒ | 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 UEC. |
Backup Lamps Malfunction
- Ignition OFF, disconnect the harness connector at the inoperative backup lamp.
- Ignition OFF, exterior lamps OFF, test for less than 5 ohms between the appropriate ground circuit terminal listed below and ground.
- Connect a test lamp between the appropriate control circuit terminal listed below and ground.
- Command the Reverse Light Test ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
- If all circuits test normal, replace the inoperative tail lamp circuit board.
| • | Left tail lamp ground terminal 1 - 3 Door |
| • | Left tail lamp ground terminal 6 - 5 Door |
| • | Right tail lamp ground terminal 6 - 3 Door |
| • | Right tail lamp ground terminal 1 - 5 Door |
| ⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
| • | Left backup lamp control terminal 2 - 3 Door |
| • | Left backup lamp control terminal 1 - 5 Door |
| • | Right backup lamp control terminal 5 - 3 Door |
| • | Right backup lamp control terminal 6 - 5 Door |
| ⇒ | If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the REC. |
| ⇒ | If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the REC. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for REC or UEC replacement, setup, and programming |
Backup Lamps Malfunction Manual Transmission
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/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Backup Lamp Switch Signal | 1 | 1 | 1 | -- |
Backup Lamp - Left Control | B2545 00 | B2545 00 | 1 | -- |
Backup Lamp - Right Control | B3880 00 | B3880 00 | 1 | -- |
Backup Lamp Switch Ground | -- | 1 | -- | -- |
Left Rear Stop/Turn Lamp Ground | -- | 1 | -- | -- |
Right Rear Stop/Turn Lamp Ground | -- | 1 | -- | -- |
1. Backup Lamps Malfunction | ||||
Circuit/System Description
The underhood electrical center (UEC) provides the normally open backup lamp switch with voltage. When the transmission is placed in the reverse position, the backup lamp switch closes providing a ground path through G104. The UEC responds to the flow of voltage by sending a serial data message to the rear electrical center (REC) requesting the backup lamps be illuminated. The REC applies battery voltage to the backup lamps control circuit illuminating the backup lamps. Once the driver moves the gear selector out of the REVERSE position, a message is sent by the UEC via serial data requesting the REC to remove battery voltage from the backup lamps control circuit. The backup lamps are permanently grounded at G403.
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Exterior Lighting Systems Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Ignition ON, observe the scan tool Reverse Gear Switch parameter while operating the gear selector in and out of the reverse position. The parameter should change between Active and Inactive as the gear selector is operated.
- With a scan tool, command the Reverse Light Test ON and OFF. The backup lamps should turn ON and OFF when commanded.
| ⇒ | If the parameter does not change as the gear selector is operated, refer to Backup Lamp Switch Malfunction. |
| ⇒ | If the backup lamps do not illuminate when commanded, refer to Backup Lamps Malfunction. |
Circuit/System Testing
Backup Lamp Switch Malfunction
- Ignition OFF, disconnect the harness connector at the backup lamp switch.
- Ignition OFF, exterior lamps OFF, test for less than 5 ohms between the ground circuit terminal A and ground.
- Ignition ON, verify the scan tool Reverse Gear Switch parameter is Inactive.
- Install a 3A fused jumper wire between the signal circuit terminal B and ground. Verify the scan tool Reverse Gear Switch parameter is Active.
- If all circuits test normal, replace the backup lamp 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 B for a short to ground. If the circuit tests normal, replace the UEC. |
| ⇒ | 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 UEC. |
Backup Lamps Malfunction
- Ignition OFF, disconnect the harness connector at the inoperative backup lamp.
- Ignition OFF, exterior lamps OFF, test for less than 5 ohms between the appropriate ground circuit terminal listed below and ground.
- Connect a test lamp between the appropriate control circuit terminal listed below and ground.
- Command the Reverse Light Test ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
- If all circuits test normal, replace the inoperative tail lamp circuit board.
| • | Left tail lamp ground terminal 1 - 3 Door |
| • | Left tail lamp ground terminal 6 - 5 Door |
| • | Right tail lamp ground terminal 6 - 3 Door |
| • | Right tail lamp ground terminal 1 - 5 Door |
| ⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
| • | Left backup lamp control terminal 2 - 3 Door |
| • | Left backup lamp control terminal 1 - 5 Door |
| • | Right backup lamp control terminal 5 - 3 Door |
| • | Right backup lamp control terminal 6 - 5 Door |
| ⇒ | If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the REC. |
| ⇒ | If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the REC. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for REC or UEC replacement, setup, and programming |
