B3133
DTC B3127, B3128, B3132, B3133, B3137, or B3138
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of the diagnostic category.
DTC Descriptors
DTC B3127
- LF Door Only, Unlock Circuit Low
DTC B3128
- LF Door Only, Unlock Circuit High
DTC B3132
- All Unlock Circuit Low
DTC B3133
- All Unlock Circuit High
DTC B3137
- All Door Lock Circuit Low
DTC B3138
- All Door Lock Circuit High
Diagnostic Fault Information
Circuit/System Description
The body control module (BCM) controls the door lock, passenger door unlock and driver door unlock relays. Voltage is applied to the appropriate relay through the door lock/unlock control circuit when the BCM senses a door lock/unlock switch activation or a keyless entry lock or unlock command.
Conditions for Running the DTC
The system voltage must be between 9-16 volts.
Conditions for Setting the DTC
B3127
The BCM detects a short to ground in the driver door unlock relay control circuit while commanding the driver door unlock relay.
B3128
The BCM detects an open in the driver door unlock relay control circuit.
B3132
The BCM detects a short to ground in the door unlock control circuit while commanding the door unlock relay.
B3133
The BCM detects an open in the door unlock control circuit.
B3137
The BCM detects a short to ground in the door lock control circuit while commanding the door lock relay.
B3138
The BCM detects an open in the door lock control circuit.
Action Taken When the DTC Sets
* The BCM stores the DTC to memory.
* The power door locks will not operate
Conditions for Clearing the DTC
* This DTC will change from current to history when the fault is no longer present.
* A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.
* The technician issues a scan tool CLEAR DTCs command.
Circuit/System Testing
1. Ignition OFF, disconnect the appropriate relay.
2. Test for less than 1 ohm of resistance between the relay coil ground circuit and ground.
• If greater than the specified range, test the relay ground circuit for an open/high resistance.
3. Connect a test lamp between the relay coil control circuit and the relay coil ground circuit.
4. Command the appropriate relay ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
• If the test lamp is always OFF, test the relay coil control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
• If the test lamp is always ON, test the relay coil control circuit for a short to voltage. If the circuit tests normal, replace the BCM
5. If all circuits test normal, test or replace the appropriate relay.
Component Testing
Relay Test
1. Ignition OFF, disconnect the applicable relay.
2. Test for 60-200 ohms of resistance between terminals 85 and 86.
• If the resistance is not within the specified range, replace the relay.
3. Test for infinite resistance between the following terminals:
* 30 and 86
* 30 and 87
* 30 and 85
* 85 and 87
• If less than infinite resistance, replace the relay.
4. Test for less than 2 ohms of resistance between terminals 30 and 87A.
• If greater than 2 ohms, replace the relay.
5. Install a 3-amp fused jumper wire between relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Measure for less than 2 ohms of resistance between terminals 30 and 87.
• If greater than 2 ohms, replace the relay.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests
* Relay Replacement (Attached to Wire Harness) Relay Replacement (Within an Electrical Center)
* Control Module References for BCM replacement, setup and programming. Programming and Relearning