Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSAUDI199590 QUATTRO SPORT V6-2.8L (AAH)REPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTCOMPUTERS AND CONTROL SYSTEMSCAMSHAFT POSITION SENSORTESTING AND INSPECTION
1995 Audi 90 Quattro Sport V6-2.8L (AAH)
Camshaft Position Sensor: Testing and Inspection
1995 Audi 90 Quattro Sport V6-2.8L (AAH)SECTION Testing and Inspection
CHECKING BATTERY POSITIVE VOLTAGE (B+) SUPPLY
- Connect VAG 1598 test box and VAG 1598/11 adapter harness to the Engine Control Module (ECM) and wiring harness. Refer to VAG 1598 Pin Out Box Connecting. Connecting VAG 1598/31 Test Box
- Connect multimeter (Fluke 83 or equivalent) between test box socket 7 (positive) and Ground (GND).
- Switch ignition ON.
^ Specified value: minimum 9 volts
- Connect multimeter to socket 45 (GND) and socket 7 (positive).
^ Specified value: minimum 9 volts
If one of the specified values is not obtained:
- Connect VAG 1598 test box and VAG 1598/11 adapter harness to engine wiring harness only.
- Check wiring between Camshaft Position (CMP) sensor and ECM for continuity and/or short circuit according to wiring diagram.
- Check for continuity of GND wire from CMP sensor connector terminal 3 to GND.
^ Specified value: maximum 1.0 ohm
- Check positive wire from terminal 1 of CMP sensor connector to test box socket 7 for continuity.
^ Specified value: maximum 1.0 ohm
- Check both wires for short to each othen
If one specified value is not obtained:
- Repair break in wiring and/or short between CMP sensor connector and ECM connector C-.
CMP sensor ECM connector C
connector terminal terminal
1 (B+) 7
2 (GND) GND
If there is neither break in wiring nor short circuit:
- Replace ECM .
CHECKING FUNCTION
NOTE:
To test CMP sensor function, disconnect the 4-pin harness connector from the ignition coil power output stage, then check DTC memory.
- Check voltage supply to CMP sensor.
- Connect VAG 1598 test box and VAG 1598/11 adapter harness to ECM wiring harness. Connecting VAG 1598/31 Test Box
- Connect VAG 1527 voltage tester between test box sockets 8 (CMP sensor signal) and 46 (positive).
- Operate starter a few seconds.
^ LED tester must blink briefly (every 2nd engine revolution).
If the LED tester does not blink:
- Switch ignition off and disconnect 3-pin connector on CMP sensor.
- Check signal wire for continuity from CMP sensor connector terminal 2 and test box socket 8.
^ Specified value: maximum 1.0 ohm
If the specified value is not obtained:
- Repair short and/or open circuit in wiring between CMP sensor connector and ECM connector C.
CMP sensor ECM connector C
connector terminal terminal
2 (signal) 8
If there is no open or short circuit in wiring:
- Connect multimeter (Fluke 83 or equivalent) between test box socket 8 and Ground.
- Switch ignition ON.
^ Specified value: 4.0 volts minimum
If specified value NOT obtained:
^ Replace ECM.
If specified value is obtained:
^ Replace CMP sensor.
- Connect VAG 1598 test box and VAG 1598/11 adapter harness to the Engine Control Module (ECM) and wiring harness. Refer to VAG 1598 Pin Out Box Connecting. Connecting VAG 1598/31 Test Box
- Connect multimeter (Fluke 83 or equivalent) between test box socket 7 (positive) and Ground (GND).
- Switch ignition ON.
^ Specified value: minimum 9 volts
- Connect multimeter to socket 45 (GND) and socket 7 (positive).
^ Specified value: minimum 9 volts
If one of the specified values is not obtained:
- Connect VAG 1598 test box and VAG 1598/11 adapter harness to engine wiring harness only.
- Check wiring between Camshaft Position (CMP) sensor and ECM for continuity and/or short circuit according to wiring diagram.
- Check for continuity of GND wire from CMP sensor connector terminal 3 to GND.
^ Specified value: maximum 1.0 ohm
- Check positive wire from terminal 1 of CMP sensor connector to test box socket 7 for continuity.
^ Specified value: maximum 1.0 ohm
- Check both wires for short to each othen
If one specified value is not obtained:
- Repair break in wiring and/or short between CMP sensor connector and ECM connector C-.
CMP sensor ECM connector C
connector terminal terminal
1 (B+) 7
2 (GND) GND
If there is neither break in wiring nor short circuit:
- Replace ECM .
CHECKING FUNCTION
NOTE:
To test CMP sensor function, disconnect the 4-pin harness connector from the ignition coil power output stage, then check DTC memory.
- Check voltage supply to CMP sensor.
- Connect VAG 1598 test box and VAG 1598/11 adapter harness to ECM wiring harness. Connecting VAG 1598/31 Test Box
- Connect VAG 1527 voltage tester between test box sockets 8 (CMP sensor signal) and 46 (positive).
- Operate starter a few seconds.
^ LED tester must blink briefly (every 2nd engine revolution).
If the LED tester does not blink:
- Switch ignition off and disconnect 3-pin connector on CMP sensor.
- Check signal wire for continuity from CMP sensor connector terminal 2 and test box socket 8.
^ Specified value: maximum 1.0 ohm
If the specified value is not obtained:
- Repair short and/or open circuit in wiring between CMP sensor connector and ECM connector C.
CMP sensor ECM connector C
connector terminal terminal
2 (signal) 8
If there is no open or short circuit in wiring:
- Connect multimeter (Fluke 83 or equivalent) between test box socket 8 and Ground.
- Switch ignition ON.
^ Specified value: 4.0 volts minimum
If specified value NOT obtained:
^ Replace ECM.
If specified value is obtained:
^ Replace CMP sensor.
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.