B1A87

B1A87-14-ESCL UNLOCK CONTROL - CIRCUIT SHORT TO GROUND OR OPEN





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

Theory of Operation

For vehicles with a manual transmission, the Body Control Module (BCM) provides a switched ground path for the Radio Frequency (RF) Hub module park switch detection circuit. The RF Hub uses this circuit as one of the inputs to determine if the vehicle conditions are correct for locking and unlocking the steering column through the Electric Steering Column Lock (ESCL) module. The BCM provides this ground for the RF Hub module when the vehicle speed is less than 5.0 km/h (3.1 mph) and the ignition is switched from either ignition OFF to ON for the ESCL unlock function or from ON to OFF for the ESCL lock function.

- When Monitored:
With the ignition on.

Output on (short to ground check).

Output off (open check).

- Set Condition:
The BCM monitors the voltage signal from the RF Hub and detects if the (T824) TRS Park Signal circuit is either open of shorted to ground.





1. CHECK FOR ACTIVE DTC
1. Turn the ignition on.
2. With the scan tool, erase DTCs.
3. Turn the ignition off and wait 30 seconds.
4. Turn the ignition on and wait 30 seconds.
5. With the scan tool, read DTCs.

Does the scan tool display this DTC as active?

Yes

- Go To 2

No

- Test complete, the condition or conditions that originally set this DTC are not present at this time. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals, and correct pin tension.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

2. CHECK THE (T824) TRS PARK SIGNAL CIRCUIT AT THE BCM




1. Turn the ignition off.
2. Disconnect the BCM D harness connector.
3. Turn the ignition on.
4. Measure the voltage between ground and the (T824) TRS Park Signal circuit.

Is the voltage above 10.0 volts?

Yes

- Replace the BCM. Body Control Module - Removal.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Go To 3

3. CHECK THE (T824) TRS PARK SIGNAL CIRCUIT FOR A SHORT TO GROUND




1. Turn the ignition off.
2. Disconnect the RF Hub Module C1 harness connector.
3. Measure the resistance between ground and the (T824) TRS Park Signal circuit.

Is the resistance above 10k Ohms?

Yes

- Go To 4

No

- Repair the short to ground in the (T824) TRS Park Signal circuit.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

4. CHECK THE (T824) TRS PARK SIGNAL CIRCUIT FOR AN OPEN




1. Measure the resistance of the (T824) TRS Park Signal circuit between the RF Hub Module C1 harness connector and the BCM D harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Replace the RF Hub Module. Radio Frequency Module (RF Hub) - Removal.
- Perform the RADIO FREQUENCY HUB (RF HUB) VERIFICATION TEST. . RF Hub Verification Test

No

- Repair the open in the (T824) TRS Park Signal circuit.
- Perform the BODY VERIFICATION TEST. Body Verification Test.