Circuit Description
The camshaft position (CMP) sensor works in conjunction with a single tooth reluctor wheel on the bank 2 intake camshaft. The engine control module (ECM) pulls up the CMP sensor signal circuit to 5 volts and monitors this voltage. As the reluctor wheel tooth rotates past the sensor, the sensors internal circuitry pulls the signal circuit to ground, creating a square wave signal that is used by the ECM. The reluctor wheel tooth covers 180 degrees of the camshaft circumference. This causes the CMP signal voltage to transition once per crankshaft revolution. This signal, when combined with the crankshaft position (CKP) sensor signal, enables the ECM to determine exactly which cylinder is on a firing stroke. The ECM can then properly synchronize the ignition system, the fuel injectors, and the knock control. Note: As long as the CKP signal is available, the engine can start and run, even if there is no CMP sensor signal, the ECM will default to a non-sequential fuel injector operation.
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
The CMP signal is not rational.
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. |
Conditions for Clearing the DTC
| • | 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 non-emission related diagnostic. |
| • | Clear the DTC with a scan tool. |
Diagnostic Aids
Use the J 35616 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector. Using this kit prevents damage to the harness or component terminals. Refer to Using Connector Test Adapters in Wiring Systems. For an intermittent, refer to Symptoms - Engine Controls .
This DTC will set with an intermittent failure of the switched battery positive feed, the CMP sensor signal circuit, or the sensor ground. A hard failure of any one of these circuits should set DTC P0340.
Check for the following conditions:
| • | Poor connections at the ECM or at the component--Inspect the harness connectors for any backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection. |
| • | A damaged harness--Inspect the wiring harness for any damage. |
If a repair is necessary, refer to Wiring Repairs or Connector Repairs in Wiring Systems.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step tests for an intermittent open or high resistance in the CMP sensor signal and ground circuits.
-
This step tests for an intermittent short between the CMP signal and ground circuits.
-
This step tests for an intermittent short to voltage or short to ground on the CMP signal circuit.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | ||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |
2 |
Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 3 |
Using a DMM, test the resistance of the CMP sensor signal and ground circuits individually while moving the harness in various locations, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. Both of the circuits should measure low resistance. A fluctuation in the resistance will indicate the area of a possible concern, refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 4 | |
Using a DMM, test the CMP sensor signal and ground circuits for continuity between them while moving the harness in various locations, refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems. The DMM should indicate OL. Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 5 | |
Is the voltage within the specified range? | 4.5-4.9 V | Go to Step 6 | Go to Step 7 | |
6 |
Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 8 |
7 | Repair the circuit as necessary, refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 9 | -- |
8 | Replace the camshaft position sensor. Refer to Camshaft Position Sensor Replacement . Did you complete the replacement? | -- | Go to Step 9 | -- |
9 |
Does the DTC run and pass? | -- | Go to Step 10 | Go to Step 2 |
10 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK | |
