Vauxhall Workshop Service and Repair Manuals

DTC B0468 or B0470-B0472

Diagnostic Instructions

DTC Descriptors

Diagnostic Fault Information

Circuit/System Description

When the engine turns off while the Stop/Start Mode, the auxiliary coolant pump will be activated. Therefore, the engine control module (ECM) grounds the auxiliary coolant pump relay control circuit, which will switch the auxiliary coolant pump relay. With the relay contacts closed, battery voltage is supplied to the auxiliary coolant pump. The auxiliary coolant pump clutch will be activated.

Conditions for Running the DTC

Engine is running.

Conditions for Setting the DTC

B0468

The ECM detects an over temperature error.

B0470

The ECM detects a short to ground at the auxiliary coolant pump relay control circuit.

B0471

The ECM detects a short to voltage at the auxiliary coolant pump relay control circuit.

B0472

The ECM detects an open at the auxiliary coolant pump relay control circuit.

Action Taken When the DTC Sets

B0470

The auxiliary coolant pump always active.

B0468, B0471 or B0472

The auxiliary coolant pump is inoperative.

Conditions for Clearing the DTC

The condition for setting the DTC is no longer present.

Reference Information

Schematic Reference

Engine Cooling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Stop/Start System Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Ignition ON, command the auxiliary coolant pump ON and OFF using the scan tool ECM Auxiliary Coolant Pump output control. The auxiliary coolant pump should turn ON and OFF.

Circuit/System Testing

1. Ignition OFF, remove the KR31 Coolant Pump Relay - Auxiliary.
2. Ignition ON, test for greater than 11 V between the ignition circuit terminal 85 at the KR31 Coolant Pump Relay - Auxiliary and ground.

⇒	If less than the specified value, test the ignition circuit for a short to ground or an open/high resistance.

3. Ignition OFF, disconnect the X1 harness connector at the K20 Engine Control Module.
4. Ignition ON, test for less than 0.3 V between the control circuit terminal 86 at the KR31 Coolant Pump Relay - Auxiliary and ground.

⇒	If greater than the specified value, test the control circuit for a short to voltage.

5. Ignition OFF, test for infinite resistance between the control circuit terminal 86 at the KR31 Coolant Pump Relay - Auxiliary and ground.

⇒	If less than the specified value, test the control circuit for a short to ground.

6. Test for less than 5 Ω between the KR31 Coolant Pump Relay - Auxiliary control circuit terminal 86 and the control circuit terminal 68 X1 at the K20 Engine Control Module.

⇒	If greater than the specified value, test the control circuit for an open/high resistance.

7. If all circuits test normal, test or replace the KR31 Coolant Pump Relay - Auxiliary and verify the DTC does not reset.

⇒	If the DTC resets, replace the K20 Engine Control Module.

Component Testing

Static Test

1. Ignition OFF, disconnect the KR31 Coolant Pump Relay - Auxiliary.
2. Test for 60-180 Ω between the B+ terminal 85 and the control terminal 86 of the KR31 Coolant Pump Relay - Auxiliary.

⇒	If not within the specified range, replace the KR31 Coolant Pump Relay - Auxiliary.

3. Test for the resistance between the following terminals:

•

30 and 86

•

30 and 87

•

30 and 85

•

85 and 87

⇒	If not the specified value, replace the KR31 Coolant Pump Relay - Auxiliary.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for engine control module replacement, setup, and programming