Camshaft Position Sensor, Checking
Camshaft Position Sensor, Checking
Special tools, testers and auxiliary items required
• Multimeter
• wiring diagrams
• Use only gold-plated terminals when servicing terminals in harness connector of Camshaft Position (CMP) Sensor (G40).
Test requirements
• Fuses for Engine Control Module (ECM) (J623) OK.
• Battery voltage at least 12.5 volts.
• All electrical consumers such as, lights and rear window defroster, switched off.
• Vehicles with automatic transmission, shift selector lever into position " P" or "N".
• A/C switched off.
• Ground (GND) connections between engine/transmission/chassis OK.
• Ignition switched off.
Test procedure
- Perform a preliminary check to verify the customers complaint. Refer to => [ Preliminary Check ] Preliminary Check.
Start diagnosis
- Pull engine cover out of first mount at front arrow 1, then at right rear arrow 2 and finally at left rear arrow 3.
CAUTION!
The use of nails, paper clips, or another unauthorized materials to back-probe electrical harness connectors is strictly prohibited and may cause damage to the electrical harness connectors, terminal ends or damage to a component. Use only the manufacturers test lead kit or an equivalent aftermarket test lead kit for back-probing all electrical harness connectors.
- Using the low current voltage tester , check for voltage between terminal 1 and terminal 2 with the electrical harness connector connected to Camshaft Position (CMP) Sensor ( G40).
- Operate the starter briefly.
The LED must blink.
• Voltage testers do not go out completely during low current pickup between activations by the ECM, but rather continue to glow a little and then get significantly brighter during activation.
- Switch ignition off.
If the LED does not blink:
Checking voltage supply
- Using a Multimeter, check the following wiring connection for voltage.
- Switch the ignition on.
Specified value: about 5 V.
- Switch the ignition off.
Checking signal wire
If the manufacturers test box is being used. Perform the following step.
- Install the Adapter Cable (121 Pin) (VAG1598/31 ).
- Check sensor G40 integrity
- Using multimeter, check the resistance at:
- If readings not in range, replace G40
- If readings within range, continue with diagnosis.
- Using a Multimeter , check the following wiring connection for voltage.
- Reconnect G40 connector
- Switch the ignition on.
Specified value: approx. 5 V.
- Switch the ignition off.
Checking Ground (GND)
- Using a Multimeter , check the following wiring connection for voltage.
Specified value: about 10 V.
If the specified values are obtained:
- Replace Camshaft Position (CMP) Sensor (G40).
If the specified values are not obtained:
Checking resistance
- Using a Multimeter, check the following wiring connections for an open circuit.
• Camshaft Position (CMP) Sensor (G40)
Specified resistance 1.5 ohms max.
- Check the wiring for a short circuit to Battery positive (+) or an open circuit.
- If necessary, repair the wiring connection.
- Erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Mode 04 - Erase DTC Memory.
- Perform a road test to verify repair.
If the DTC does not return:
Repair complete, Generate readiness code. Refer to => [ Readiness Code ] Readiness Code.
- End diagnosis.
If the DTC does return and no malfunction is detected in the wiring and the voltage supply was OK:
- Replace the Motronic Engine Control Module (ECM) (J623). Refer to => [ Motronic Engine Control Module, Replacing ] Motronic Engine Control Module, Replacing.
- Assembly is performed in the reverse of the removal.
Final procedures
After the repair work, the following work steps must be performed in the following sequence:
1. Check the DTC memory. Refer to => [ Diagnostic Mode 03 - Read DTC Memory ] Diagnostic Mode 03 - Read DTC Memory.
2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Mode 04 - Erase DTC Memory.
3. If the DTC memory was erased, generate readiness code. Refer to => [ Readiness Code, Setting ] Readiness Code, Setting.
End of Diagnosis.