Volkswagen Touareg 3.0 TDI engine jerks

Intake swirl flaps

This new post reflects a failure registered in the flap motor of the intake manifold used in 3.0 TDi Common Rail engines of the Volkswagen Touareg. They have two electric motors, one for each bank.

The function of these two motors is to configure the spiroid swirls of intake air, depending on the regime and load of the engine.

At low regimes, the swirl valves are closed, improving the quality of the mixture. Between 1,250 and 2,750 rpm the swirl valves open continuously; from 2,750 rpm onwards the swirl valves stay fully open. In start-up phase and in emergency phase the swirl valves are also fully open.

SYMPTOM

The vehicle responds with some unusual jerks. The engine failure engine light stays lit.

If the error codes are read, the following stored failures, depending on the symptom, may be detected:

  

19556 (P3100) - Intake manifold flap motor – Short circuit to earth

19557 (P3101) – Intake manifold flap motor – Interruption/short circuit to earth

19559 (P3103) – Intake manifold flap motor – Faulty

19784 (P3328) – Intake manifold flap motor 2 – Short circuit to earth

19785 (P3329) – Intake manifold flap motor 2 – Interruption/short circuit to earth

19787 (P3331) – Intake manifold flap motor 2 – Faulty

MAINTENANCE SERVICE

1- Check earth of the electrical installation inside the coolant regulator housing.

2- Check the intake manifold flap motor. The electrical connector comprises a total of 5 wires:

 

PIN 1: Ground

PIN 2: 12V power downstream of main relay

PIN 3: Control of the swirl valve regulating motor of the intake manifold

PIN 4: Signal position

PIN 5: Control of regulating motor

To check the control signal of the motor, an oscilloscope should be used, connected as follows:

Wiring diagram of the 3.0 TDI (BKS) engine. (Information taken from www.dis-net.com)

Wiring diagram of the 3.0 TDI (BKS) engine. (Information taken from www.dis-net.com) 

The signal to be obtained, if operation is correct, is shown in the following figure: 

  

Oscillogram of swirl valve intake manifold motor
  

REMEDY

Intake manifold flap motor

1- Restore earth of the coolant regulator housing

2- If the motor's signals are not correct, the problem may be caused by an internal wear of the swirl valve. In this case it must be replaced. 

3- The motor's signal is correct and the problem persists, check the movement of the rod. For this purpose, it is advisable to remove the attachment of the push rod between the motor and the swirl valve. Try to manually move the push rod, which should move smoothly and with a certain lightness.

Rod between the engine intake manifold flap and the swirl valve shaft

If it does not work properly, the intake manifold should be cleaned or replaced.