With Generic Scan Tool

Check Camshaft Position (CMP) Sensor

Recommended special tools and equipment







- VAG1526A hand multimeter
- V.A.G 1527 B Voltage Tester
- VAG1594A connector test kit
- VAG1598/31 test box

The Camshaft Position (CMP) sensor provides the ignition position for cylinder 1.
During a failure, knock control is switched off and the ignition angle is retarded slightly since a cylinder allocation is no longer possible.

Engine will continue to run without Camshaft Position (CMP) sensor signal and can also be restarted:
- When a malfunction is recognized, the Engine Control Module (ECM) initiates one ignition spark per cylinder for each crankshaft rotation.
- The offset of one engine rotation will have no noticeable effect on the injection. Instead of occurring with intake valves open, injection will be "advanced" (in front of closed intake valve). This has only a minor effect on the quality of the mixture preparation.

NOTE:
- Camshaft Position (CMP) Sensor 2 -G40- is located at front of right cylinder head (bank 1).







- Camshaft Position (CMP) Sensor -G163- is located at rear of left cylinder head (bank 2). To reach the harness connector, the line to Engine Coolant Level (ECL) Warning Switch at bottom on reservoir must be disconnected, bolts -arrows- of coolant reservoir must be unscrewed and set it aside. Coolant hoses-1- and -2- remain connected.

Test requirement:
- Ignition switched off.







- Remove the engine cover (arrows).

Checking activation







- Connect voltage tester e.g. V.A.G 1527 B with measuring probes and connector adapters from V.A.G 1594 A between socket 2 (CMP sensor signal) and socket 1 (B+); the harness connector remains connected.

NOTE: Connector sockets are numbered respectively on the rear side of the connector.

- Operate starter for a few seconds.
- LED must blink.

NOTE: Voltage testers do not go out completely during low current pick-up between activations by the ECM, but rather continue to glow a little and then get significantly brighter during activation.

- Switch ignition off.

If LED does not blink:

Checking voltage supply







- Disconnect electrical harness connector (arrow) from Camshaft Position (CMP) Sensor -G40-.







- Disconnect electrical harness connector (arrow) from Camshaft Position (CMP) Sensor -G163-.







- Connect multimeter for voltage measurement as follows:

Harness connector Measure to
Terminal
1 Engine Ground (GND)

- Switch ignition on.
- Specified value: about 5 V
- Switch ignition off.

Checking signal wire







- Connect multimeter for voltage measurement as follows:

Harness connector Measure to
Terminal
2 Engine Ground (GND)

- Switch ignition on.
- Specified value: approx. battery voltage
- Switch ignition off.

Checking Ground (GND) wire







- Connect multimeter for voltage measurement as follows:

Harness connector Measure to
Terminal
3 B+

- Specified value: about 10 V

If all specified values are being reached and the LED does not blink (measured between terminal 1 and 2 with starter and connector connected):
- Replace Camshaft Position (CMP) sensor.

If specified values are not obtained:

Checking wire connections between Camshaft Position (CMP) sensor and Engine Control Module (ECM)
- Connect test box to wiring harness of Engine Control Module (ECM); ECM is not connected. Test Box, Connecting For Wiring Test
- Check the following wire connections for open circuit according to wiring diagram:







- Camshaft Position (CMP) Sensor 2 -G40- (bank 1)

Harness connector Test box
Terminal Socket
1 (B+) 98
2 (signal) 87
3 (Ground -GND-) 108







- Camshaft Position (CMP) Sensor 2 -G163- (bank 2)

Harness connector Test box
Terminal Socket
1 (B+) 98
2 (signal) 86
3 (Ground -GND-) 108

- Specified value: Wire resistance max 1.5 Ohm
- Also check wires for short circuit to each other as well as to B+ and Ground (GND).
- Specified value: Infinity Ohms (no continuity)
- If necessary, repair wire connection.

Final procedures
After repair work, the following work steps must be performed in the mentioned sequence:
1 - Check DTC memory "Mode 3: Check DTC memory". Diagnostic Mode 3: Check DTC Memory
2 - If necessary, erase DTC memory "Mode 4: Reset/erase diagnostic data". Diagnostic Mode 4: Reset/Erase Diagnostic Data
3 - Generate readiness code. Readiness Code, Generating

- End diagnosis and switch ignition off.