Operation of camshaft timing control — AUDI

AJG ALF
The timing of the inlet camshafts is controlled according to engine load and engine speed. The timing of the exhaust camshafts is not variable.

The electrically operated solenoid valves for camshaft adjustment transmit oil pressure to the mechanical camshaft adjusters.

The mechanical camshaft adjusters then advance the inlet camshafts for both cylinder banks, which means that the inlet valves will open earlier.

Testing operation of camshaft timing control

Connect fault reader V.A.G 1551 (V.A.G 1552) and select engine electronics control unit with the "Address word" 01. When doing this the engine must be running at idling speed.
(Connecting fault reader and selecting engine electronics control unit => Page
01-3
.)

Rapid data transfer
HELP
Select function XX
Indicated on display:

Press keys 0 and 8 for the function "Read measured value block" and confirm entry with Q key.

Read measured value block
Enter display group number XXX
Indicated on display:

Press the keys 0, 9 and 0 to select Display Group 90 and confirm entry with Q key.

Read measured value block 90
⇒
1
2
3
4
Indicated on display:

Check display value for camshaft timing control.

Display zones
1 · 2 · 3 · 4
Display Group 90: Camshaft timing control
Display · xxx rpm · CS-ctrl. OFF / CS-ctrl. ON · xx.x °crankshaft · xx.x °crankshaft
Indicates · Engine speed / (in steps of 40 rpm) · Camshaft timing / control off/on · Feedback signal for / adjustment, Bank 1 / (via Hall sender -G163) · Feedback signal for / adjustment, Bank 2 / (via Hall sender -G40)
Range · min.: 600 rpm / max.: 6920 rpm · --- · min.: -3.0 °cr/shaft / max.: 25.0 °cr/shaft · min.: -3.0 °cr/shaft / max.: 25.0 °cr/shaft
Specification · Current engine speed · CS-ctrl. OFF · -3.0...6.0 °cr/shaft · -3.0...6.0 °cr/shaft
Note · Normal position · Normal position

Take vehicle for a test drive.

Important:
Secure fault reader to rear seat and operate from this location. When doing this, always observe the relevant safety precautions => Page
24-1
.
Accelerate rapidly from standstill in 1st gear (manual gearbox) or in selector lever position 2 (automatic gearbox) and check display values for camshaft timing control (display zones 2...4).

Display zones
1 · 2 · 3 · 4
Display Group 90: Camshaft timing control at 2000...3400 rpm
Display · xxxx rpm · CS-ctrl. OFF / CS-ctrl. ON · xx.x °crankshaft · xx.x °crankshaft
Indicates · Engine speed / (in steps of 40 rpm) · Camshaft timing / control off/on · Feedback signal for / adjustment, Bank 1 / (via Hall sender -G163) · Feedback signal for / adjustment, Bank 2 / (via Hall sender -G40)
Range · min.: 600 rpm / max.: 6920 rpm · --- · min.: -3.0 °cr/shaft / max.: 25.0 °cr/shaft · min.: -3.0 °cr/shaft / max.: 25.0 °cr/shaft
Specification · Current engine speed · CS-ctrl. ON · 16.0....25.0 °cr/shaft · 16.0....25.0 °cr/shaft
Note · Adjusted position / If readouts do not match specifications, test solenoid valves for / camshaft adjustment =>Page 28-44

Notes:

Display zone 2 indicates whether or not the engine control unit is activating the camshaft timing control.
CS-ctrl. OFF = camshaft timing control not activated
CS-ctrl. ON = camshaft timing control activated (display will only show "CS-ctrl. ON" during a test drive)

Display zones 3 and 4 indicate whether or not the camshaft positions have actually been adjusted (feedback signal via Hall senders).
Normal position: -3.0 °....6.0°cr/shaft
Adjusted position: 16.0 °....25.0°cr/shaft

If a value of between 6.0 °cr/shaft and 16.0 °cr/shaft appears in display zone 3 (or display zone 4) during the test drive, this means that the camshaft adjustment solenoid valves are diverting the oil pressure to the mechanical camshaft adjusters correctly, but that the mechanical adjusters are not reaching their end stop positions (e.g. because they are not moving freely).