Backup Lamps Malfunction (MT)
Diagnostic Instructions
Diagnostic Fault Information
Circuit
|
Short to Ground
|
Open/High Resistance
|
Short to Voltage
|
Signal Performance
|
Reverse Gear Signal
|
2
|
1
|
1
|
1
|
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
backup lamps. The backup 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 backup lamp control circuit.
Reference Information
Schematic Reference
Exterior Lights 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 Backup Lamps Relay Command test. The
backup lamp should be ON/OFF.
Circuit/System Testing
| 1. |
Ignition OFF, disconnect the
harness connector at the B16 Backup Lamp Switch. |
| 2. |
Disconnect the negative
terminal of the C1 Battery. |
| 3. |
Test for less than 5 Ω
between the ground circuit harness connector terminal 2 and
ground. |
| ⇒ |
If greater than the specified value, test the
ground circuit for an open/high resistance. |
| 4. |
Reconnect the negative
terminal to the C1 Battery. |
| 5. |
Disconnect the X1 and X2
harness connector at the K20 Engine Control Module. |
| 6. |
Ignition ON, test for less
than 0.3 V at the B16 Backup Lamp Switch signal circuit harness
connector terminal 1 and ground. |
| ⇒ |
If greater then the specified value, test the
signal circuit for a short to voltage. |
| 7. |
Ignition OFF, test for
infinite resistance between the B16 Backup Lamp Switch signal
circuit harness connector terminal 1 and ground. |
| ⇒ |
If lower then the specified value, test the signal
circuit for a short to ground. |
| 8. |
Connect the harness connector
at the B16 Backup Lamp Switch. |
| 9. |
Disconnect the negative
terminal of the C1 Battery. |
| 10. |
Engage reversing gear.
|
| 11. |
Disconnect the appropriate
harness connector at the K20 Engine Control Module and test for
less than 5 Ω between the terminal listed below and
ground: |
| |
• |
Terminal 28 X1 with LDE, LDD
or LLU |
| |
• |
Terminal 34 X1 with LPL or
LPV |
| |
• |
Terminal 75 X1 with LSF
|
| ⇒ |
If greater then the specified value, test the
signal circuit for an open/high resistance. If the circuit test
normal, test or replace the B16 Backup Lamp Switch. |
| 12. |
Disengage reversing
gear. |
| 13. |
Disconnect the appropriate
harness connector at the K20 Engine Control Module and test for
infinite resistance between the terminal listed below and
ground: |
| |
• |
Terminal 28 X1 with LDE, LDD
or LLU |
| |
• |
Terminal 34 X1 with LPL or
LPV |
| |
• |
Terminal 75 X1 with LSF
|
| ⇒ |
If less than the specified value, test or replace
the B16 Backup Lamp Switch. |
| 14. |
If all circuit tests normal,
replace the K20 Engine Control Module. |
Component Testing
Static Test
| 1. |
Ignition OFF, disconnect the
harness connector at the B16 Backup Lamp Switch. Reversing gear
engaged, test for less than 5 Ω at the B16 Backup Lamp Switch
terminal 1 and terminal 2. |
| ⇒ |
If greater than the specified value replace the
B16 Backup Lamp Switch. |
| 2. |
Reversing gear disengaged,
test for infinite resistance at the B16 Backup Lamp Switch terminal
1 and terminal 2. |
| ⇒ |
If less than the specified value replace the B16
Backup Lamp Switch. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
|
