Reverse Lamps Malfunction - MT
Diagnostic Instructions
Diagnostic Fault Information
Circuit
| Short to Ground
| Open/High Resistance
| Short to Voltage
| Signal Performance
|
Reverse Gear Signal
| 1
| 1
| 2
| --
|
1. Reverse Gear Lamp Inoperative
2. Reverse Gear Lamp Always ON
|
Circuit/System Description
When the transmission is placed in the reverse position, the engine control module (ECM) sends a serial data message to the body control module (BCM). The message indicates that the gear selector is in the reverse position. The BCM applies battery voltage to the reverse lamps. The reverse lamps are permanently grounded. Once the driver moves the gear selector out of the reverse position, a message is sent by the ECM via serial data requesting the BCM to remove battery voltage from the reverse lamp control circuit.
Reference Information
Schematic Reference
Exterior Lamps Schematics
Connector End View Reference
Component Connector End Views
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, perform the Reverse Lamps Relay test. The reverse lamp should be ON/OFF.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the B16 Reverse Lamp Switch.
- Test for less than 5 Ω between the ground circuit harness connector terminal B and ground.
⇒ | If greater than the specified value, test the ground circuit for an open/high resistance. |
- Disconnect the X2 harness connector at the K20 Engine Control Module.
- Ignition ON, test for less than 0.3 V at the B16 Reversing Lamp Switch signal circuit harness connector terminal A and ground.
⇒ | If greater than the specified value, test the signal circuit for a short to voltage. |
- Ignition OFF, test for infinite resistance between the B16 Reverse Lamp Switch signal circuit harness connector A and ground.
⇒ | If lower than the specified value, test the signal circuit for a short to ground. |
- Connect the harness connector at the B16 Reverse Lamp Switch.
- Reverse gear engaged, test for less than 85 kΩ between the K20 Engine Control Module X2 harness connector terminal listed below and ground:
• | Terminal 87 with LXV or 2H0 |
⇒ | If greater than the specified value, test the signal circuit for an open/high resistance. If the circuit test normal, test or replace the B16 Reverse Lamp Switch. |
- Reverse gear disengaged, test for infinite resistance between the K20 Engine Control Module X2 harness connector terminal listed below and ground:
• | Terminal 87 with LXV or 2H0 |
⇒ | If lower than the specified value, test or replace the B16 Backup Lamp Switch. |
- If all the circuits test normal, replace the K20 Engine Control Module.
Component Testing
Static Test
- Ignition OFF, disconnect the harness connector at the B16 Reverse Lamp Switch. Reversing gear engaged, test for less than 80 kΩ at the B16 Reverse Lamp Switch terminal A and terminal B.
⇒ | If greater than the specified value replace the B16 Reverse Lamp Switch. |
- Reversing gear disengaged, test for infinite resistance at the B16 Reverse Lamp Switch terminal A and terminal B.
⇒ | If less than the specified value replace the B16 Reverse Lamp Switch. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
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