Volt

DTC P257D-P257F

The hybrid powertrain control module 2 applies B+ to the bonnet ajar signal 2 circuit and monitors the voltage to determine the position of the bonnet. The bonnet ajar switch contains a multiplexed resistor. This resistor will vary the voltage seen by the hybrid powertrain control module 2 by pulling down the applied voltage based on the position of the switch.

Propulsion system is active.

P257D

The bonnet ajar switch signal 2 voltage as measured by the hybrid powertrain control module 2 is not within a valid voltage range.

P257E

The hybrid powertrain control module 2 detects a short to ground in the bonnet ajar signal input to the hybrid powertrain control module 2.

P257F

The hybrid powertrain control module 2 detects a short to voltage or an open/high resistance in the bonnet ajar signal input to the hybrid powertrain control module 2.

The engine will start and run whenever the vehicle is in Service Mode or the vehicle speed is less than 5 kph (3 mph).

DTCs P257D, P257E, and P257F are Type B DTCs.

Schematic Reference

Immobiliser Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Bonnet Ajar Indicator Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

1. Vehicle in Service Mode.
2. Observe the scan tool ECM Bonnet Position parameter. With the bonnet open, the Bonnet Position parameter should be Open. With the bonnet closed, the Bonnet Position parameter should be Closed.

⇒	If the parameter does not change

Refer to Circuit/System Testing.

⇓	If the parameter changes

3. All OK.

1. Vehicle OFF and all vehicle systems OFF, disconnect the harness connector at the B55 bonnet ajar switch. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 10 Ω between the ground circuit terminal C and ground.

⇒	If 10 Ω or greater

2.1.	Vehicle OFF

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

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

⇒	If less than 2 Ω, repair the open/high resistance in the ground connection.

⇓	If less than 10 Ω

3. Vehicle in Service Mode.
4. Verify DTC P257F is set as current

⇒	If DTC P257F is not set as current

4.1.	Vehicle OFF, disconnect the harness connector at the ECM.

4.2.	Test for infinite resistance between the signal circuit and ground.

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

⇒	If infinite resistance, replace the ECM

⇓	If DTC P257F is set as current

5. Install a 5 A fused jumper wire between the signal circuit terminal A and earth.
6. Verify DTC P257E is set as current.

⇒	If DTC P257E is not set as current

6.1.	Vehicle OFF, disconnect the harness connector at the ECM.

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

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

⇓	If less than 1 V

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

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

⇒	If less than 2 Ω, replace the BCM.

⇓	If DTC P257E is set as current

7. Test or replace the B55 bonnet ajar switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.