Volt

DTC B2955

When a keyless entry transmitter is inserted into the transmitter pocket/slot and the ignition mode switch is pressed, the transponder embedded in the transmitter is energised by the immobiliser aerial exciter coil. The transponder transmits a signal to the body control module (BCM). The BCM then compares this value to a value stored in memory. If the value is correct, the BCM will send the prerelease password via the serial data circuit to the engine control module (ECM). If the learned key code does not match or a transponder value is not received, the BCM will send the start disable password to the ECM.

Vehicle is ON or in Service Mode.

The BCM detects a circuit fault on the immobiliser aerial circuits.

Schematic Reference

Immobiliser Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Immobiliser Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

1. Vehicle OFF and all vehicle systems OFF, disconnect the harness connector at the K89 immobiliser control module. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 30 Ω between the low reference circuit terminal 1 and ground.

⇒	If 30 Ω or greater

2.1.	Vehicle OFF, disconnect the harness connector at the K9 BCM.

2.2.	Test for less than 2 Ω in the low reference circuit end to end.

⇒	If 2 Ω or greater, repair the open/high resistance in the circuit.

⇒	If less than 2 Ω, replace the K9 BCM.

⇓	If less than 30 Ω

3. Connect a test lamp between the B+ circuit terminal 3 and ground.
4. Verify the test lamp illuminates or flashes for three seconds after ignition mode switch is pressed.

⇒	If the test lamp does not illuminate

4.1.	Vehicle OFF, disconnect the harness connector at the K9 BCM.

4.2.	Test for infinite resistance between the B+ circuit and ground.

⇒	If less than infinite resistance, repair the short to ground on the circuit.

⇓	If infinite resistance

4.3.	Test for less than 2 Ω in the B+ circuit end to end.

⇒	If 2 Ω or greater, repair the open/high resistance in the circuit.

⇒	If less than 2 Ω, replace the K9 BCM.

⇓	If the test lamp illuminates

5. Vehicle in Service Mode.
6. Test for 12-13 V between the serial data circuit terminal 2 and ground.

⇒	If less than 12 V

6.1.	Vehicle OFF, disconnect the harness connector at the K9 BCM.

6.2.	Test for infinite resistance between the serial data circuit and ground.

⇒	If less than infinite resistance, repair the short to ground on the circuit.

⇓	If infinite resistance

6.3.	Test for less than 2 Ω in the serial data circuit end to end.

⇒	If 2 Ω or greater, repair the open/high resistance in the circuit.

⇒	If less than 2 Ω, replace the K9 BCM.

⇒	If greater than 13 V

6.1.	Vehicle OFF, disconnect the harness connector at the K9 BCM, vehicle ON.

6.2.	Test for less than 1 V between the signal circuit and ground.

⇒	If 1 V or greater, repair the short to voltage on the circuit.

⇒	If less than 1 V, replace the K9 BCM.

⇓	If within 12-13 V

7. Replace the K89 immobiliser control module.
8. Verify DTC B2955 is not set.

⇒	If DTC B2955 is set

Replace the K9 BCM.

⇓	If DTC B2955 is not set or is set as history

9. All OK.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.