Diagnostic Instructions
DTC Descriptors
DTC P0340: Camshaft Position (CMP) Sensor Circuit
DTC P0341: Camshaft Position (CMP) Sensor Performance
Circuit/System Description
The camshaft position (CMP) sensor correlates the crankshaft to camshaft position so that the engine control module (ECM) can determine which cylinder is ready to be fueled by an injector. As the camshaft rotates, the reluctor wheel interrupts a magnetic
field produced by the sensor which creates a signal that is sent the ECM on the signal circuit. The CMP sensor circuits are directly connected to the ECM.
Conditions for Running the DTC
| • | DTCs P0335, P0336, P0641, or P0651 are not set. |
| • | The engine is cranking or running. |
| • | MAF is greater than 3 grams per second. |
| • | The DTC runs continuously once the above conditions are met. |
Conditions for Setting the DTC
The ECM does not detect a signal from the CMP sensor for greater than 3 seconds.
Action Taken When the DTC Sets
DTCs P0340 and P0341 are Type B DTCs.
Conditions for Clearing the DTC
DTCs P0340 and P0341 are Type B DTCs.
Diagnostic Aids
The following conditions could also set the DTC:
| • | Physical damage to the CMP sensor or the reluctor wheel |
| • | Excessive play or looseness of the CMP sensor or the reluctor wheel |
| • | Improper installation of the CMP sensor or the reluctor wheel |
| • | Foreign material passing between the CMP sensor and the reluctor wheel |
| • | Excessive air gap between the CMP sensor and the reluctor wheel |
Reference Information
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Electrical Information Reference
DTC Type Reference
Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Engine Control Module Scan Tool Information
Circuit/System Verification
- Start the engine, observe the DTC information with a scan tool. DTC P0340, or P0341 should not set.
- Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the CMP sensor.
- Test for less than 5 ohms between the low reference circuit terminal B and ground.
| ⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM. |
- Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal C and ground.
| ⇒ | If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM. |
| ⇒ | If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM. |
- Test for 2-3 volts between the signal circuit terminal A and ground.
| ⇒ | If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM. |
| ⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM. |
- If all circuits test normal, test or replace the CMP sensor.
Component Testing
- Ignition OFF, inspect the CMP sensor for correct installation or damage.
| ⇒ | If the sensor is loose, incorrectly installed, or damaged, replace the CMP sensor. |
- Connect the CMP sensor harness connector to the CMP sensor.
- Ignition ON, observe the scan tool CMP Active counter parameter while passing a flat steel object across the tip of the sensor repeatedly. The CMP Active counter parameter should increment with each pass of the steel object.
| ⇒ | If the parameter does not increment, replace the CMP sensor. |
Repair Instructions
Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
