Electric Coolant Pump Checking

Electric Coolant Pump Checking

• Use only gold-plated terminals when servicing terminals in the electrical harness connector of Coolant Pump (V50).

Special tools, testers and auxiliary items required

• Multimeter.

• Wiring diagram.

Test requirements

• The Auxiliary Engine Coolant Pump Relay (J496) OK.

• The Coolant Pump (V50) 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 connections between engine/transmission/chassis OK.

• Ignition switched off.

• Engine cold.

Test procedure

- Perform a preliminary check to verify the customers complaint. Refer to => [ Preliminary Check ] Preliminary Check.

Start diagnosis

- Disconnect the Coolant Pump (V50) electrical harness connector.

Checking voltage

Switch the ignition On.

- Using a multimeter, check the Coolant Pump (V50) electrical harness connector terminal 1 to Ground for voltage.





Specified value: Battery voltage.

Switch the ignition Off.

If the specified value was Not obtained:

- Check the wiring from the Coolant Pump (V50) electrical connector terminal 1 to the Auxiliary Engine Coolant Pump Relay (J496) socket 2/87 for a short circuit to Ground, high resistance, or an open circuit.

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

- If necessary, repair the wiring connection.

If the specified value was obtained:

Checking Ground

- Using a multimeter, check the Coolant Pump (V50) electrical connector terminal 2 to Ground for resistance.





Specified value: 1.5 ohms Max.

If the specification was Not obtained:

- Check the wiring from the Coolant Pump (V50) electrical connector terminal 1 to Ground connection on electronic fan control for or an open circuit, high resistance, a short circuit to Battery (+) or Ground.

- 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 supply was Not OK:

- Replace the Auxiliary Engine Coolant Pump Relay (J496).

- Erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 09.

- Perform a road test to verify repair.

If the DTC does not return:

Generate readiness code. Refer to => [ Readiness Code ] Monitors, Trips, Drive Cycles and Readiness Codes.

If the DTC returns, no malfunction is detected in the wiring and voltage supply was OK:

- Replace the Coolant Pump (V50).

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 Modes 01 - 09.

2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 09.

3. If the DTC memory was erased, generate readiness code. Refer to => [ Readiness Code ] Monitors, Trips, Drive Cycles and Readiness Codes.