B2126

B2126-SENSOR SUPPLY VOLTAGE LOW





For a complete wiring diagram, refer to the Wiring Information.

- When Monitored:
With the Headlamps on.

- Set Condition:
The Auto Headlamp Leveling Module (AHLM)detects a low condition on the output circuit.





1. CHECK FOR ACTIVE DTC
1. Turn the ignition on.
2. With the scan tool, record and erase AHLM Module DTCs.
3. Wait 30 seconds.
4. With the scan tool, read AHLM Module DTCs.

Does the scan tool display: B2126-SENSOR SUPPLY VOLTAGE LOW?

Yes

- Go To 2

No

- The condition that caused this code to set is not present at this time. Check for an intermittent condition by inspecting the related wiring harness for chafed, pierced, pinched, and partially broken wires. Also inspect the related connectors for broken, bent, pushed out, spread, corroded, or contaminated terminals.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

2. HEADLAMP LEVELING SWITCH
1. Turn the ignition off.
2. Disconnect Headlamp Leveling Switch.
3. Turn the ignition on.
4. With the scan tool, read AHLM Module DTCs.

Does the scan tool display this DTC as active?

Yes

- Go To 3

No

- Replace Headlamp Leveling Switch.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

3. (L961) HEADLAMP LEVELING SENSOR 5 VOLT SUPPLY CIRCUIT OPEN
1. Turn the ignition off.
2. Disconnect the HIDT Module harness connector.
3. Measure the resistance between the (L961) Headlamp Leveling Sensor 5 Volt Supply circuit and the (Z919) Ground circuit.

Is the resistance below 10K Ohms?

Yes

- Repair the (L961) Headlamp Leveling Sensor 5 Volt Supply circuit for an open condition.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Go To 4

4. (L961) HEADLAMP LEVELING SENSOR 5 VOLT SUPPLY CIRCUIT SHORTED TO GROUND
1. Measure the resistance between ground and the (L961) Headlamp Leveling Sensor 5 Volt Supply circuit.

Is the resistance below 10K Ohms?

Yes

- Repair the (L961) Headlamp Leveling Sensor 5 Volt Supply circuit for a short to ground.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Replace the Auto Headlamp Leveling Module (AHLM).
- Perform the BODY VERIFICATION TEST. Body Verification Test.