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Checking valve 1 for camshaft timing control > < Checking camshaft timing control

A4 Mk1

Motronic Fuel Injection and ignition system (4-cyl.) 07.96ä
Checking camshaft timing control
Function of camshaft timing control

The adjustment of the intake camshaft is dependent on the engine load and engine speed. The exhaust camshafts are not timed.

The solenoid valves for camshaft timing control switch oil pressure to the camshaft adjuster (mechanical adjustment device).

The mechanical camshaft adjusters then time the inlet camshafts of both banks of cylinders towards "advanced", i.e. such that the inlet valves open earlier.

Checking camshaft timing control function

  • ‒ Connect fault reader V.A.G 1551 (V.A.G 1552) and select the engine electronics control unit with the "Address word" 01. When doing this the engine must be running at idle speed
    (Connecting fault reader and selecting control unit for engine electronics .)
 
→ Indicated on display:
Rapid data transfer      HELP
Select function XX
  • ‒ Press keys 0 and 8 for the function "Read measured value block" and confirm entry with Q key.
 
→ Indicated on display:
Read measured value block 08    
Enter display group number XXX
  • ‒ Press keys 0, 2 and 5 for "Display group number 25" and confirm entry with the Q key.
  • ‒ Observe display in display zone 3.
 
→ Indicated on display:
Read measurement block 25    ⇒
    1    2    3    4

Specification: X X 0

Value: X = (no meaning)

Actuation of camshaft timing not active

  • ‒ Take the vehicle for a test drive.
Warning
Secure fault reader to the rear seat and operate from this location. When doing this, always observe the relevant safety precautions.
=> Page 24-1.
  • ‒ Accelerate the vehicle from a slow speed (1000 rpm) in 2nd gear with throttle floored.
  • ‒ Observe display in display zone 3.
 
→ Indicated on display:
Read measurement block 25    ⇒
    1    2    3    4

Specification: X X 1

Value: X = (no meaning)

Actuation of camshaft timing active

Note:

  • ◆ Display zone 3 indicates whether the engine control unit is or is not actuating the camshaft timing control.
    • ‒ "X X 0": Actuation of camshaft timing not active
    • ‒ "CAMSHAFT CONTROL ON" Actuation of camshaft timing active ("CAMSHAFT- ON" can only obtained by way of a test drive)
  • ◆ Display zone 4 indicates whether adjustment of the camshaft has actually taken place (feedback via Hall sender).
    • ‒ Normal position: -3,0°crankshaft...6.0 °crankshaft
    • ‒ Switched position:16,0°crankshaft...25.0°crankshaft
  • ◆ If a value between6.0°crankshaft and 16.0°crankshaft is displayed in fields 3 and/or 4 during test drive, the camshaft adjustment solenoid valves are switching the oil pressure properly to the respective mechanical camshaft adjuster, but this is not able to reach its end position (e.g. on account of stiffness).
  • ‒ If specification is not reached, then check the valve for camshaft timing control => Page 28-16.

Checking valve 1 for camshaft timing control > < Checking camshaft timing control