Function of camshaft timing control — AUDI

The inlet camshaft is adjusted as a function of load and engine speed. There is no adjustment of the exhaust camshaft.

The camshaft adjustment solenoid valve causes oil pressure to be applied to the camshaft adjuster (mechanical adjuster).

The camshaft adjuster then "advances" the inlet camshafts, i.e. the inlet valves open sooner.

Checking operation of camshaft timing control

Connect vehicle diagnostic, testing and information system VAS 5051 or fault reader V.A.G 1551 and select engine electronics control unit with "address word" 01 => Page
01-8
.
Engine must be idling.

Rapid data transfer
HELP
Select function XX
Indicated on display:

Press keys 0 and 4 for "Basic setting" function and confirm entry with Q key.

Basic setting
Enter display group number XXX
Indicated on display:

Press keys 0, 9 and 4 for "Display group number 94" and confirm entry with Q key.

Basic setting
94
⇒
1
2
3
4
Indicated on display:

Check camshaft timing control specification.

Display zones
1 · 2 · 3 · 4
Display group 94: Camshaft timing control
Display · xxx rpm · Cam.TC.OFF · Test off
Readout · Engine speed / (in increments of 40) · Camshaft timing control off / on · Test result, bank 1
Operating range · min.: 660 rpm / max.: 6600 rpm · Cam.TC.OFF / Cam.TC.ON · Test off / Test on / Syst. OK / Syst. not OK · / / /
Specification · Current engine speed · Cam.TC.OFF · Test off
Note · Normal position

Increase engine speed until
display zone 2 shows "Cam.TC.ON" and
display zone 3 shows "Test on".

Display zones
1 · 2 · 3 · 4
Display group 94: Camshaft timing control
Dand 4isplay · xxx rpm · Cam.TC.ON · Test on
Readout · Engine speed / (in increments of 40) · Camshaft timing control off / on · Test result, bank 1
Operating range · min.: 660 rpm / max.: 6600 rpm · Cam.TC.OFF / Cam.TC.ON · Test off / Test on / Syst. OK / Syst. not OK · / / /
Specification · Current engine speed · Cam.TC.ON · Test on
Note

Maintain engine speed until display zone 3 shows Syst. OK.

Display zones
1 · 2 · 3 · 4
Display group 94: Camshaft timing control
Display · xxx rpm · Cam.TC.OFF · Syst. OK
Readout · Engine speed / (in increments of 40) · Camshaft timing control off / on · Test result, bank 1
Operating range · min.: 660 rpm / max.: 6600 rpm · Cam.TC.OFF / Cam.TC.ON · Test off / Test on / Syst. OK / Syst. not OK · / / /
Specification · Current engine speed · Cam.TC.OFF · Syst. OK
Note

If reading does not match specification in display zone 3, check camshaft adjustment solenoid valves => Page
28-33
.

Checking operation of camshaft timing control

Connect vehicle diagnostic, testing and information system VAS 5051 or fault reader V.A.G 1551 and select engine electronics control unit with "address word" 01 => Page
01-8
.
Engine must be idling.

Rapid data transfer
HELP
Select function XX
Indicated on display:

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

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

Press keys 0, 9 and 1 for "Display group number 91" and confirm entry with Q key.

Read measured value block 91
⇒
1
2
3
4
Indicated on display:

Check camshaft timing control specification.

Display zones
1 · 2 · 3 · 4
Display group 91: Camshaft timing control
Display · xxx rpm · xx.x % · Cam.TC.OFF · xx.x °CA
Readout · Engine speed / (in increments of 40) · Load · Camshaft timing control off / on · Adjustment feedback / (via Hall sender -G40)
Operating range · min.: 660 rpm / max.: 6800 rpm · min.: 0 % / max.: 120 % · Cam.TC.OFF / Cam.TC.ON · min.: -3.0 °CA / max.: 25.0 °CA
Specification · Current engine speed · Cam.TC.OFF · -6.0...6.0 °CA
Note · Normal position

Run a test drive.

Attention:
Attach fault reader to rear seat and operate it from there. Pay attention to safety precautions => Page
24-1
.
Rapidly accelerate vehicle from a standstill in first gear (manual gearbox) or in selector lever position "2" (automatic gearbox) and in doing so check camshaft timing control specifications (display zones 3 and 4).

Display zones
1 · 2 · 3 · 4
Display group 91: Camshaft timing control at 2000...3600 rpm
Display · xxxx rpm · xx.x % · Cam.TC.ON · xx.x °CA
Readout · Engine speed / (in increments of 40) · Load · Camshaft timing control off / on · Adjustment / feedback / (via Hall sender -G40)
Operating range · min.: 750 rpm / max.: 6920 rpm · min.: 0 % / max.: 145 % · Cam.TC.OFF / Cam.TC.ON · min.: -3.0 °CA / max.: 25.0 °CA
Specification · 2000...3600 rpm · greater than 140 % · Cam.TC.ON · 17.0....25.0 °CA
Note · Switched position / If reading does not match specification, check camshaft adjustment solenoid valve / => Page 28-33

Notes:

Display zone 3 shows whether or not camshaft timing control is being actuated by engine control unit.
"Cam.TC.OFF": Camshaft timing control actuation not active
"Cam.TC.ON": Camshaft timing control actuation active

Display zone 4 shows whether camshaft timing control has actually been implemented (feedback via Hall sender).
Normal position: -6.0 °CA...6.0°CA
Switched position: 17.0 °CA...25.0°CA

If, when performing test drive, display zone 3 shows "Cam.TC.ON" and display zone 4 indicates a value between 6.0 ° and 16.0 °CA: Camshaft adjustment solenoid valve is switching oil pressure in the proper manner to the mechanical camshaft adjuster, but the adjuster is not able to reach its end position (e.g. stiff).