Coolant Pump, Checking

Special tools and workshop equipment required 

• Multimeter VAG 1526 or Multimeter VAG 1715
• Connector test kit VAG 1594
• Wiring diagram

Test requirements 

• Fuses in E-box (plenum chamber, left) must be OK: Refer to appropriate SYSTEMS WIRING DIAGRAM
  Fig 1: Identifying Fuses In E-Box (Plenum Chamber, Left)

  Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.
• Motronic Engine Control Module (ECM) Power Supply Relay 2 -J670- must be OK, check: appropriate SYSTEMS WIRING DIAGRAM
• Auxiliary Engine Coolant (EC) Pump Relay -J496-, -position A° must be OK, checking: appropriate SYSTEMS WIRING DIAGRAM
• 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-.

-- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data.

-- Generate readiness code.

If pump runs:

-- Disconnect connection between pump and battery.

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

-- 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 Ω

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

Specified value: ∞ Ω

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

Wire resistance: max. 1.5 Ω

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: Refer to appropriate SYSTEMS WIRING DIAGRAM

-- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data.

-- Generate 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.

-- Check wire between test box and relay carrier for open circuit according to wiring diagram.

Terminal 5 + socket 48

Wire resistance: max. 1.5 Ω

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

Specified value: ∞ Ω

-- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data.

-- Generate readiness code.

If no malfunction is detected in the wire:

-- Replace Motronic Engine Control Module (ECM) -J220-.

Final Procedures 

After the 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 .