Coolant Fan Control Module 2, 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 -J271- must be OK, check: 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.
• Parking brake must be engaged or else daylight driving lights will be switched on.
• For vehicles with automatic transmission, selector lever must be in P.
• If vehicle is equipped with an A/C system, it must be switched off.
• Ground (GND) connections between engine and chassis must be OK.

Test sequence 

-- Disconnect 4-pin connector from Coolant Fan Control (FC) Control Module 2 -J671- (-2-).

Checking voltage supply 

-- Connect multimeter to terminals 1+4 and 2+4 of connector for voltage measurement.

-- Switch ignition on.

Specified value: at least 10.0 V

-- Switch ignition off.

If there is no voltage:

-- Check wires between 4-pin connector (terminals 1 and 2) and Motronic Engine Control Module (ECM) Power Supply Relay -J271- for open circuit according to wiring diagram.

Wire resistance: max. 1.5 Ω

-- Check for open circuit in wire between 4-pin connector terminal 4 and Ground (GND) according to wiring diagram.

Wire resistance: max. 1.5 Ω

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

-- Generate readiness code.

If there is no malfunction in voltage supply:

-- 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 4-pin connector for open circuit according to wiring diagram.

Terminal 3 + socket 104

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 wire and there was voltage present between terminals 1+4 and 2+4:

-- Replace Coolant Fan Control (FC) Control Module 2 -J671- with Coolant Fan 2 -V177-.

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 .