After-Run Coolant Pump, Checking

After-Run Coolant Pump, Checking

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

Special tools, testers and auxiliary items required

• Multimeter.

• Wiring diagram.

Test requirements

• The Coolant Circulation Pump Relay (J151) OK.

• The After-Run Coolant Pump (V51) fuse 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. Refer to => [ General Diagnosis ] General Diagnosis.

Start diagnosis

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





Checking voltage

Switch the ignition on.

- Using a multimeter, check the After-Run Coolant Pump (V51) electrical connector terminal 1 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 After-Run Coolant Pump (V51) electrical connector terminal 1 to the Coolant Circulation Pump Relay (J151) socket 2/87 for a short circuit to Ground (GND), or an open circuit.

- Check the electrical harness connector for damage, corrosion, lose 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 After-Run Coolant Pump (V51) electrical connector terminal 2 to Ground (GND) 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, lose or broken terminals.

- If necessary, repair the faulty wiring connection.

If no malfunction is detected in the wiring:

- Replace the After-Run Coolant Pump (V51).

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 ] Readiness Code.

- End of diagnosis.