After-Run Coolant Pump, Checking

Special tools and workshop equipment required 

• Multimeter.
• Wiring diagram.

Test requirements

• The Coolant Circulation Pump Relay -J151- OK.
• The After-Run Coolant Pump -V51- fuse OK.
  Fig 1: Identifying Fuses On E-Box In Engine Compartment, Left Side

  Courtesy of AUDI OF AMERICA, LLC
• 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 .

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 Ω 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 .
2. If necessary, erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
3. If the DTC memory was erased, generate readiness code. Refer to READINESS CODE .

-- End of diagnosis.