Coolant Pump, Checking

Coolant Pump, Checking

• Use only gold-plated terminals when servicing terminals in the electrical harness connector of Coolant Pump (V51).

Special tools, testers and auxiliary items required

• Multimeter.

• Wiring diagram.

Test requirements

• Fuse (SA1) OK.

• Fuse (SA4) OK.

• The Coolant Circulation Pump Relay (J151) OK.

• Suppressor (C24) OK

• Battery voltage at least 12.5 volts.

• All electrical consumers such as, lights and rear window defroster, switched off.

• Vehicles with automatic transmission, shift selector lever into position "P" or "N".

• A/C switched off.

• Ground (GND) connections between engine/transmission/chassis OK.

• Ignition switched off.

• Engine cold.

Test procedure

- Perform a preliminary check to verify the customers complaint. Diagnostic Mode 09 - Read Vehicle Information.

Start diagnosis

- Disconnect the Coolant Pump (V51) electrical harness connector - 3 -.





Checking voltage

Switch the ignition on.

- Using a multimeter, check the Coolant Pump (V51) electrical harness connector terminal 2/31 to Ground (GND) for voltage.





Specified value: battery voltage.

Switch the ignition off.

If the specified value was not obtained:

- Check the wiring from the Coolant Pump (V51) electrical connector terminal 2/31 to the Generator (GEN) (C) terminal B (+) for a short circuit to Ground (GND), or an open circuit.

- Check the electrical harness connector for damage, corrosion, loose or broken terminals.

- If necessary, repair the wiring connection.

If no malfunctions are found in the wiring:

Checking Ground (GND)

- Using a multimeter, check the Coolant Pump (V51) electrical harness connector terminal 1 to Coolant Circulation Pump Relay (J151) socket 7/87 for resistance.





Specified value: 1.5 ohms Max.

If the specification was not obtained:

- Check the wiring for a short circuit to, Battery (+), or an open.

- Check the electrical harness connector for damage, corrosion, loose or broken terminals.

- If necessary, repair the faulty wiring connection.

If no malfunction is detected in the wiring and the voltage was OK:

- Replace the Coolant Pump (V51).

- Erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Mode 04 - Erase DTC Memory.

- Perform a road test to verify repair.

If the DTC does not return:

Repair complete, Generate readiness code. Refer to => [ Readiness Code Description ] Diagnostic Mode 09 - Read Vehicle Information.

- End diagnosis.

If the DTC does return and no malfunction is detected in the wiring and the Ground (GND) was not OK:

- Replace the Coolant Circulation Pump Relay (J151).

Final procedures

After repair work, the following work steps must be performed in the following sequence:

1. Check the DTC memory. Refer to => [ Diagnostic Mode 03 - Read DTC Memory ] Diagnostic Mode 03 - Read DTC Memory.

2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Mode 04 - Erase DTC Memory.

3. If the DTC memory was erased, generate readiness code. Refer to => [ Readiness Code ] Engine.

End of diagnosis