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.
Camshaft Position (CMP) Sensors , Checking
This procedure is used to check Camshaft Position (CMP) Sensors G40, G300, G163, G301.
- The following procedure is used to diagnose all Camshaft Position (CMP) Sensors.
Special tools, testers and auxiliary items required
- Multimeter.
- Wiring diagram.
Test requirements
- The Engine Control Module (ECM) J623 fuses 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 → General Diagnosis .
Start diagnosis
Checking activation
- Remove the front engine cover - arrows -.
- Remove the rear engine cover - arrows -.
- Disconnect the electrical harness connector of the Camshaft Position (CMP) Sensor G40 to be tested.
- Switch the ignition on.
- Using a Multimeter , Check the Camshaft Position (CMP) Sensor electrical harness connector terminals 1 to 3 for voltage.
Specified value: about 5.0 V
- Switch the ignition off.
If the specification was not obtained:
Checking wiring
If the manufacturers test box is being used. Perform the following step.
- Install the test box. Refer to → 24 - FUEL INJECTION SYSTEM .
If the manufacturers test box is not being used. Perform the following step.
- Remove the Engine Control Module (ECM) J623. Refer to → Engine Control Module (ECM) J623 , Removing and Installing .
- Using a Multimeter , Check the Camshaft Position (CMP) Sensor electrical harness connector to the Engine Control Module (ECM) J623 electrical harness connector T60 for an open circuit.
| Camshaft Position (CMP) Sensor G40 electrical harness connector terminals | Engine Control Module (ECM) J623 electrical harness connector T60 terminals or test box sockets |
|---|---|
| 1 Battery positive (+) | 11 |
| 2 (signal) | 25 |
| 3 Ground (GND) | 40 |
| Camshaft Position (CMP) Sensor 3 G300 electrical harness connector terminals | Engine Control Module (ECM) J623 electrical harness connector T60 terminals or test box sockets |
|---|---|
| 1 Battery positive (+) | 11 |
| 2 (signal) | 54 |
| 3 Ground (GND) | 40 |
| Camshaft Position (CMP) Sensor 2 G163 electrical harness connector terminals | Engine Control Module (ECM) J623 electrical harness connector T60 terminals or test box sockets |
|---|---|
| 1 Battery positive (+) | 11 |
| 2 (signal) | 9 |
| 3 Ground (GND) | 40 |
| Camshaft Position (CMP) Sensor 4 G301 electrical harness connector terminals | Engine Control Module (ECM) J623 electrical harness connector T60 terminals or test box sockets |
|---|---|
| 1 Battery positive (+) | 11 |
| 2 (signal) | 24 |
| 3 Ground (GND) | 40 |
Specified value: 1.5 Ω Max.
If the specified value was not obtained:
- Check the wiring connection for an open circuit, short circuit to Battery (+) or Ground (GND).
- Check the wiring connection for damage, corrosion, lose or broken terminals.
- If necessary, repair the faulty wiring connection.
If no malfunction is found in the wiring and voltage supply was OK:
- Replace the Camshaft Position (CMP) Sensor G40 → 15 - ENGINE - CYLINDER HEAD, VALVETRAIN .
If no malfunction is found in the wiring and voltage supply was not OK:
- Replace the Engine Control Module (ECM) J623. Refer to → Engine Control Module (ECM) J623 , Removing and Installing .
Assembly is performed in the reverse order of removal, note the following:
Final procedures
After repair work, the following work steps must be performed in the mentioned sequence:
- Check the DTC memory.
- If necessary, erase the DTC memory. Refer to Diagnostic Mode 04: Reset/delete Diagnostic Data .
- If the DTC memory was erased, generate readiness code. Refer to Readiness Code .
- End diagnosis and switch ignition off.
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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.