DTC Descriptors
DTC P0340: Intake Camshaft Position (CMP) Sensor Circuit Bank 1DTC P0345: Intake Camshaft Position (CMP) Sensor Circuit Bank 2
Diagnostic Fault Information
Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Intake CMP Position Sensor 5-Volt Reference Voltage | P0069, P0107, P0340, P0345, P0365, P0390, P0452, P0532, P0641, P1183, P2228 | P0340, P0345 | P0069, P0641, P2229, P2261 | -- |
Intake CMP Position Sensor Signal | P0340, P0341, P0345, P0346 | P0340, P0345 | P0341, P0346 | -- |
Intake CMP Position Sensor Low Reference | -- | P0340, P0345 | -- | -- |
Typical Scan Tool Data
Circuit | Normal Range | Short to Ground | Open | Short to Voltage |
|---|---|---|---|---|
Intake CMP Position Sensor Bank 1 5-Volt Reference Voltage | Incrementing from 0-255 counts | stops incrementing | stops incrementing | stops incrementing |
Intake CMP Position Sensor Bank 1 Signal | Incrementing from 0-255 counts | stops incrementing | stops incrementing | -- |
Intake CMP Position Sensor Bank 1 Low Reference | Incrementing from 0-255 counts | -- | stops incrementing | -- |
Circuit | Normal Range | Short to Ground | Open | Short to Voltage |
|---|---|---|---|---|
Intake CMP Position Sensor Bank 2 5-Volt Reference Voltage | Incrementing from 0-255 counts | stops incrementing | stops incrementing | stops incrementing |
Intake CMP Position Sensor Bank 2 Signal | Incrementing from 0-255 counts | stops incrementing | stops incrementing | -- |
Intake CMP Position Sensor Bank 2 Low Reference | Incrementing from 0-255 counts | -- | stops incrementing | -- |
Circuit/System Description
The 4X camshaft position (CMP) sensor circuits consist of an engine control module (ECM) supplied 5-volt reference circuit, low reference circuit, and an output signal circuit. The CMP sensor is an internally magnetic biased digital output integrated circuit sensing device. The sensor detects magnetic flux changes of the teeth and slots of a 4-tooth reluctor wheel attached to the camshaft. As each reluctor wheel tooth rotates past the CMP sensor, the resulting change in the magnetic field is used by the sensor electronics to produce a digital output pulse. The sensor returns a digital ON/OFF DC voltage pulse of varying frequency, with 4 varying width output pulses per camshaft revolution that represent an image of the camshaft reluctor wheel. The frequency of the CMP sensor output depends on the velocity of the camshaft. The ECM decodes the narrow and wide tooth pattern to identify camshaft position. This information is then used to determine the optimum ignition and injection points of the engine. The ECM also uses CMP sensor output information to determine the camshaft relative position to the crankshaft, to control camshaft phasing.
Conditions for Running the DTC
| • | The engine is running. |
| • | The DTCs run continuously when the above condition is met. |
Conditions for Setting the DTC
The ECM does not detect a signal from the intake CMP sensor for more than 1 second.
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records. |
| • | The CMP actuator is commanded to the home or parked position. |
| • | The ignition system defaults to a failed CMP sensor limp home mode. |
Conditions for Clearing the DTC
| • | The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | Clear the MIL and the DTC with a scan tool. |
Diagnostic Aids
The following conditions may cause this DTC to set:
| • | Damage to the camshaft reluctor wheel |
| • | Damage to the CMP sensor |
| • | The sensor coming in coming in contact with the reluctor wheel |
| • | Foreign material passing between the sensor and the reluctor wheel |
Reference Information
Schematic Reference
Connector End View Reference
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Circuit/System Verification
- If DTCs P0641 or P0651 are set, diagnose those DTCs first. Refer to Diagnostic Trouble Code (DTC) List - Vehicle .
- With the engine running, observe the CMP Sensor parameter using the scan tool. The CMP sensor speed should match the Engine Speed parameter within 100 RPM.
- With the ignition ON and the engine OFF, use the Live Plot function on the scan tool. Select the Engine Speed parameter and the CMP Sensor parameter. Change the minimum spec to 0 RPM for both parameters. Change the maximum spec to 1,500 RPM for both parameters.
- Observe the scan tool and start the engine. The graphed lines should stay together.
| ⇒ | If the CMP sensor speed is 0, continue with Circuit/System Testing. |
| ⇒ | If the CMP sensor line deviates excessively from the engine speed line, continue with Circuit/System Testing. |
Circuit/System Testing
- With the ignition OFF, inspect the engine wiring harnesses carrying the CMP sensor circuits for the following conditions:
- Disconnect the CAM sensor with the ignition ON and the engine OFF, measure for 4.8-5.2 volts at the ECM side of the connector between the 5-volt reference circuit of the CMP sensor and a good ground.
- With the ignition ON and the engine OFF, measure for 4.8-5.2 volts at the ECM side of the connector between the CMP sensor signal circuit and a good ground.
- With the ignition ON and the engine OFF, measure for 1-3 mA, at the ECM side of the connector between the CMP sensor signal circuit and a good ground.
- Connect a fused jumper wire to a good ground.
- With the ignition ON and the engine OFF, observe the CMP Active Counter on the scan tool.
- Touch the jumper wire to the CMP sensor signal circuit repeatedly at the ECM side of the connector. The CMP Active Counter should increment.
- With the ignition ON and the engine OFF, measure for B+ at the ECM side of the connector between the low reference circuit of the CMP sensor and the battery positive post.
- Inspect the CMP sensor for looseness. Remove the CMP sensor from the engine and inspect the sensor and the O-ring for damage.
- Reconnect the CMP sensor to the engine harness.
- Turn ON the ignition, with the engine OFF.
- While observing the CMP Active Counter parameter on the scan tool, pass a steel object by the tip of the sensor repeatedly. The CMP Active Counter parameter should increment.
- With the ignition OFF, drain the engine oil , and inspect the engine oil for debris.
- . Inspect the camshaft reluctor wheel for damage.
- With the ignition OFF, inspect the timing chain, tensioner, and sprockets for wear or damage. Refer to Camshaft Timing Drive Chain Alignment Diagram .
| • | Close routing of secondary ignition wires |
| • | Close routing of aftermarket electrical equipment |
| • | Close to solenoids, motors, and relays |
| ⇒ | Correct any wire harness routing or component placement conditions, if it is determined to be a possible source of electrical interference. |
| ⇒ | If the voltage is less than 4.8 volts, test for an open in the 5-volt reference circuit between the ECM and the CMP harness connector. If the circuit tests normal, replace the control module. |
| ⇒ | If the voltage is less than 4.8 volts, test for an open or a short to ground in the CMP sensor signal circuit between the ECM and the CMP sensor connector. If the circuit tests normal, replace the control module. |
| ⇒ | If the voltage is more than 5.2 volts, test for a short to voltage in the CMP sensor signal circuit between the ECM and the CMP sensor connector. If the circuit tests normal, replace the control module. |
| ⇒ | If the amperage is more than 3 mA, test the CMP sensor signal circuit for a short to the 5-volt reference circuit between the ECM and the CMP sensor connector. If the circuit tests normal, replace the control module. |
| ⇒ | If the CMP Active Counter does not increment, replace the ECM. |
| ⇒ | If the voltage measured between the low reference circuit and the battery positive post is not the same as voltage measured between a good ground and the battery positive post, test for an open/high resistance in the low reference circuit between the ECM and the CMP sensor connector. If the circuit tests normal, replace the control module. |
| ⇒ | Repair or replace the CMP sensor, if necessary. |
| ⇒ | If the parameter does not increment, replace the CMP sensor. |
| ⇒ | If debris is found in the engine oil, inspect the internal engine components to determine the cause. |
| ⇒ | If the reluctor wheel is damaged, replace the camshaft. |
| ⇒ | If any parts are worn or damaged, replace as necessary. |
Repair Instructions
Always perform the Diagnostic Repair Verification after completing the diagnostic procedure.
