Coolant Pump, Checking

Coolant Pump, Checking

Recommended special tools and equipment
- V.A.G 1526 multimeter or V.A.G 1715 multimeter
- V.A.G 1594 connector test kit
- Wiring diagram

Test requirements







- Fuses in E-box (plenum chamber, left) must be OK
- Motronic Engine Control Module (ECM) Power Supply Relay 2 -J670- -position A1- must be OK, check
- Auxiliary Engine Coolant (EC) Pump Relay -J496-, -position A degree - must be OK, checking
- Battery voltage must be at least 11.5 volts.
- All electrical consumers such as, lights and rear window defroster must be switched off.
- Ground (GND) connections between engine and chassis must be OK.
- Ignition switched off.


Test sequence







- Disconnect 2-pin connector -1- from Coolant Pump -V36- (-2-).
- Connect coolant pump to the B+ and Ground (GND) terminals of the battery using the respective adapter cables.

Pump must run.

If pump does not run:
- Disconnect connection between pump and battery.
- Replace Coolant Pump -V36-.Disconnect 2-pin connector -1- from Coolant Pump -V36-

WARNING:
- The cooling system is under pressure.
- Danger of scalding when opening.

- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data. Diagnostic Mode 04 - Erase DTC Memory
- Generate readiness code. Readiness Code

If pump runs:
- Disconnect connection between pump and battery.







- Remove Auxiliary Engine Coolant (EC) Pump Relay -J496- from relay carrier, position A5.

NOTE: Do not use metallic tools to pry off relays from relay carrier. The terminals could conduct electricity.







- Check wire between terminal 2 of relay carrier and terminal 1 of 2-pin connector of Coolant Pump -V36- for open circuit according to wiring diagram.

Wire resistance: max. 1.5 ohm

- Also check the wire for short circuit to B+ and Ground (GND).

Specified value: infinity ohm







- Check wire between 2-pin connector terminal 2 and Ground (GND) for open circuit according to wiring diagram.

Wire resistance: max. 1.5 ohm

If no malfunctions are found in wires:
- Now check voltage supply of Auxiliary Engine Coolant (EC) Pump Relay -J496-.







- Connect multimeter to terminal 1 of relay carrier and Ground (GND) for voltage measurement.
- Switch ignition on.

Specified value: at least 10.0 V

- Switch ignition off.

If specified value is not obtained:
- Locate and repair open circuit using wiring diagram
- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data. Diagnostic Mode 04 - Erase DTC Memory
- Generate readiness code. Readiness Code

If specified value is obtained:
- Check wire to Engine Control Module (ECM) according to wiring diagram.

Checking wire to Engine Control Module (ECM)
- Connect test box to control module wiring harness, connect test box for wiring test. Test Box, Connecting For Wiring Test







- Check wire between test box and relay carrier for open circuit according to wiring diagram.
Terminal 5 + socket 48

Wire resistance: max. 1.5 ohm

- Check wire for short circuit to vehicle Ground (GND) and to B+.

Specified value: infinity ohm

- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data. Diagnostic Mode 04 - Erase DTC Memory
- Generate readiness code. Readiness Code

If no malfunction is detected in the wire:
- Replace Motronic Engine Control Module (ECM) -J220-.