Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provide an overview of each diagnostic category. |
DTC Descriptors
DTC P0340: Camshaft Position (CMP) Sensor CircuitDTC P0341: Camshaft Position (CMP) Sensor Performance
Diagnostic Fault Information
Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance |
|---|---|---|---|---|---|
CMP 5-Volt Reference | P0642 | P0340 | P0340 | P0643 | P0341 |
CMP Sensor Signal | P0340 | P0340 | P0340 | P0340 | P0341 |
CMP Low Reference | -- | P0340 | P0340 | -- | P0341 |
Typical Scan Tool Data
Circuit | Normal Range | Short to Ground | Open | Short to Voltage |
|---|---|---|---|---|
Operating Conditions: Engine running | ||||
CMP 5-Volt Reference Voltage | Yes | No | No | Yes |
CMP Sensor Signal | Yes | No | No | No |
CMP Low Reference | Yes | -- | No | -- |
Circuit/System Description
The hall effect camshaft position (CMP) sensor produces 3 ON/OFF pulses for each revolution of the camshaft. The CMP output is pulse width encoded. The engine control module (ECM) uses the CMP and crankshaft position (CKP) output pulses to determine the engine speed and position. The CMP is connected directly to the ECM by the following circuits:
| • | The 5-volt reference circuit |
| • | The low reference circuit |
| • | The CMP sensor signal circuit |
Conditions for Running the DTC
P0340
| • | The ignition is ON. |
| • | The engine is turning faster than 50 RPM. |
| • | DTC P0340 runs continuously when the above conditions are met. |
| • | DTCs P0335, P0336, P0642, or P0643 are not set. |
P0341
| • | The ignition is ON. |
| • | The engine is turning faster than 50 RPM. |
| • | DTC P0341 runs continuously when the above conditions are met. |
Conditions for Setting the DTC
P0340
The ECM does not see a CMP sensor signal for more than 2 seconds.
P0341
The ECM determines that the CMP sensor signal is out of range.
Action Taken When the DTC Sets
DTCs P0340 and P0341 are Type A DTCs.
Conditions for Clearing the MIL/DTC
DTCs P0340 and P0341 are Type A DTCs.
Diagnostic Aids
If the CMP sensor signal is lost while running, the engine will operate normally. If the CMP sensor signal is not present on start-up, the engine will not start.
Reference Information
Schematic Reference
Connector End View Reference
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Special Tools
J 38522 Variable Signal Generator
Circuit/System Verification
- If DTCs P0642 or P0643 are set, diagnose those DTCs first.
- Engine running, observe the DTC information with a scan tool. DTCs P0340 or P0341 should not set.
- Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
P0340
- Ignition OFF and scan tool disconnected for 90 seconds, disconnect the harness connector at the CMP sensor.
- Test for less than 5 ohms between low reference circuit terminal 2 of the connector and ground.
- Ignition ON, test for 4.8-5.2 volts between the 5-volt reference 1 circuit terminal 3 of the connector and ground.
- Test for 4.8-5.2 volts between the signal circuit terminal 1 of the connector and ground.
- Ignition OFF, connect a 3-amp fused jumper wire between signal circuit terminal 1 of the connector and ground.
- Ignition ON, observe the scan tool 5-Volt Reference 1 Circuit Status parameter. The parameter should display OK.
- Ignition OFF, connect the red lead of the J 38522 to the signal circuit terminal 1 of the connector. Connect the battery voltage supply to B+. Connect the black lead to ground.
- Set the J 38522 signal switch to 5 volts, the frequency to 60, and the Duty Cycle to Normal.
- Ignition ON, observe the CMP Sensor Signal Present parameter of the scan tool. The parameter should display YES.
- If all circuits test normal, replace the CMP sensor.
| ⇒ | If greater than the specified value, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM. |
| ⇒ | If less than the specified range, test the 5-volt reference 1 circuit for an open/high resistance or short to ground. If the circuit tests normal, replace the ECM. |
| ⇒ | If greater than the specified range, test the 5-volt reference 1 circuit for a short to voltage. If the circuit tests normal, replace the ECM. |
| ⇒ | If less than the specified range, test the signal circuit for an open/high resistance or short to ground. 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 the 5-Volt Reference 1 Circuit Status parameter does not display OK, test the signal circuit for a short to 5-volt reference 1. If the circuit tests normal, replace the ECM. |
| ⇒ | If the parameter does not display YES, replace the ECM. |
P0341
- Ensure that the CMP sensor circuits are not routed too closely to the fuel injector wiring, after-market add-on electrical equipment, solenoids, relays, or motors.
- Remove the front engine cover and inspect the CMP sensor for physical damage, loose or improper installation, foreign material passing between the sensor and the reluctor wheel, timing gear misalignment, or front engine cover damage.
- Inspect the CMP reluctor wheel for physical damage, improper installation, or excessive endplay or looseness.
- If no other condition is found, replace the CMP sensor.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for ECM replacement, setup, and programming |
