Camshaft Adjustment Control, Function Audi A8 D3

The adjustment of the intake 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 intake camshafts for both cylinder banks, which means that the intake valves will open earlier.

Scheme 25

Scheme 26

Scheme 27

1. Connect vehicle diagnostic, testing and information system VAS5051 or VAG1551 scan tool and select engine electronics control module by entering address word "01". See «VEHICLE DIAGNOSTIC, TESTING AND INFORMATION SYSTEM VAS5051 OR VAG1551, CONNECTING AND SELECTING FUNCTIONS»(ref-216437-S40962647232006020800000) . Engine must be idling. Indicated on display
2. Press buttons -0- and -4- to select function "Basic setting" and confirm entry by pressing -Q- button. Indicated on display
3. Press buttons -0-, -9- and -4- to select "Display Group 094" and confirm entry with -Q- button. Indicated on display
4. Check specified display value for camshaft timing control. DISPLAY GROUP 094: CAMSHAFT ADJUSTMENT CONTROL (1 OF 3) Display fields 1 2 3 4 Display Group 094: Camshaft adjustment control Display xxx RPM CS-ctrl. OFF Test OFF Test OFF Indicates Engine speed (in steps of 40 RPM) Camshaft adjustment control off/on Test result, Bank 1 Test result, Bank 2 Range min.: 550 RPM max.: 6600 RPM CS-ctrl. OFF CS-ctrl. ON Test OFF Test ON Syst. OK Syst.n.OK Test OFF Test ON Syst. OK Syst.n.OK Specified value Current engine speed CS-ctrl. OFF Test OFF Test OFF Note Normal position Normal position
5. Increase engine speed to approx.: 2000 RPM until "CS-ctrl. ON" appears in display field 2 DISPLAY GROUP 094: CAMSHAFT ADJUSTMENT CONTROL (2 OF 3) Display fields 1 2 3 4 Display Group 094: Camshaft adjustment control Display xxx RPM CS-ctrl. ON Test ON Test ON Indicates Engine speed (in steps of 40 RPM) Camshaft adjustment control off/on Test result, Bank 1 Test result, Bank 2 Range min.: 550 RPM max.: 6600 RPM CS-ctrl. OFF CS-ctrl. ON Test OFF Test ON Syst. OK Syst.n.OK Test OFF Test ON Syst. OK Syst.n.OK Specified value Current engine speed CS-ctrl. ON Test ON Test ON Note
6. Maintain engine speed until "Syst. OK" appears in display fields 3 and 4. DISPLAY GROUP 094: CAMSHAFT ADJUSTMENT CONTROL (3 OF 3) Display fields 1 2 3 4 Display Group 094: Camshaft adjustment control Display xxx RPM CS-ctrl. OFF Syst. OK Syst. OK Indicates Engine speed (in steps of 40 RPM) Camshaft adjustment control off/on Test result, Bank 1 Test result, Bank 2 Range min.: 550 RPM max.: 6600 RPM CS-ctrl. OFF CS-ctrl. ON Test OFF Test ON Syst. OK Syst.n.OK Test OFF Test ON Syst. OK Syst.n.OK Specified value Current engine speed CS-ctrl. OFF Syst. OK Syst. OK Note If the specified value is not obtained in display fields 3 and 4, test solenoid valves for camshaft adjustment. See «VALVE -1- FOR CAMSHAFT ADJUSTMENT -N205- AND VALVE -2- FOR CAMSHAFT ADJUSTMENT - N208-, CHECKING»(ref-216439-S22294190932006020800000) .

Scheme 28

1. Switch ignition on.
2. Start output Diagnostic Test Mode (DTM) and select camshaft adjustment. See «OUTPUT DIAGNOSTIC TEST MODE (DTM) (FUNCTION 03) (ENGINE CODES AUX, AKB)»(ref-216437-S12154373892006020800000) . Indicated on display When camshaft adjustment is activated, both solenoid valves should click audibly.

If this result is not obtained, perform the following tests

Scheme 29

1. Disconnect harness connector from camshaft adjustment solenoid valve which is to be tested.
2. Measure resistance between the valve contacts using multimeter (Fluke 83 or equivalent). Specification: 10 to 18 ohm

If the reading does not match the specification

1. Replace relevant camshaft adjustment solenoid valve.

Scheme 30

1. Disconnect harness connector from solenoid valve which is to be tested.
2. Connect VAG1527 diode test lamp between engine Ground (GND) and socket 1 (B+) of harness connector using test leads from VAG1594 connector test kit.
3. Operate starter for few seconds. Engine can be allowed to start. Diode test lamp should light up.

If the diode test lamp does not light up, perform the following tests

1. Test fuse for camshaft adjustment solenoid valves. See SYSTEM WIRING DIAGRAM .

If fuse is OK

Scheme 31

1. Check for continuously in wiring between socket 1 on connector and fuel pump relay via fuse See SYSTEM WIRING DIAGRAM .

Scheme 32

Scheme 33

1. Disconnect harness connector from solenoid valve which is to be tested.
2. Connect VAG1527 diode test lamp between sockets 1 (B+) and 2 of relevant solenoid valve harness connector using test leads VAG1594 connector test kit.
3. Start output Diagnostic Test Mode (DTM) and select camshaft adjustment. See «OUTPUT DIAGNOSTIC TEST MODE (DTM) (FUNCTION 03) (ENGINE CODES AUX, AKB)»(ref-216437-S12154373892006020800000) . Indicated on display

When camshaft timing control is activated diode test lamp should start flashing.

If the diode test lamp lights up continuously

Scheme 34

1. Check for short to Ground (GND) in wiring from socket 2 on connector for relevant camshaft adjustment solenoid valve.

If the diode test lamp does not flash

Scheme 35

1. Connect VAG1598/31 test box to wiring harness for engine control module. Do not connect to engine control module itself. See «WIRING AND COMPONENT CHECK WITH VAG1598/31 TEST BOX»(ref-216438-S11057563412006020800000) .
2. Check for open circuit or short to B+ in wiring of connector for relevant camshaft adjustment solenoid valve. CAMSHAFT ADJUSTMENT SOLENOID VALVE CIRCUIT TEST - OPENS/SHORTS 2-pin connector on wiring harness, terminal Socket on VAG1598/31 test box 2 115 Resistance in wiring: max. 1.5 ohms See SYSTEM WIRING DIAGRAM .
3. Repair any open or short circuits.

If no open or short circuits are identified

1. Replace Engine Control Module (ECM). See «MOTRONIC ENGINE CONTROL MODULE (ECM) -J220- (WITHOUT METAL ANTI -THEFT HOUSING), REPLACING»(ref-216438-S07554723402006020800000) .
2. Display readiness code. See «READINESS CODE, CHECKING»(ref-216437-S40758807032006020800000) . If DTC memory was erased generate readiness code. See «READINESS CODE, GENERATING»(ref-216437-S25676712792006020800000) .
3. If no malfunctions have been identified in any tests so far, replace relevant mechanical camshaft adjuster. See «CAMSHAFTS AND CAMSHAFT ADJUSTERS, REMOVING AND INSTALLING»(ref-196865-S23970725262005100900000) .