Circuit Description
The camshaft position (CMP) sensor is a hall effect switching device that works in conjunction with a single tooth reluctor wheel used to determine the position of the bank 2 exhaust camshaft. The engine control module (ECM) expects the CMP sensor signal to be low, 0 volts, as the single tooth in the reluctor wheel passes the sensor, and high, 12 volts, during the remainder of the reluctor wheel rotation. The ECM supplies a 12-volt pull up voltage on the CMP sensor signal circuit. The ECM expects to see one transition from high to low every two crankshaft revolutions. This signal, when combined with the crankshaft position (CKP) sensor signal, enables the ECM to properly synchronize ignition timing, fuel delivery and knock control. As long as the CKP signal is available, the engine can start and run. The ECM will default to a non-sequential fuel injector operation even if there is no CMP sensor signal. If the ECM detects extra or missing CMP sensor signal transitions within a certain number of crankshaft revolutions, DTC P0341 sets.
The CMP sensor has the following circuits:
| • | Ignition 1 voltage circuit |
| • | Low Reference circuit |
| • | CMP sensor signal circuit |
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
The CMP signal is inconsistent for eight or more crankshaft revolutions.
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 MIL/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: |
| - | Camshaft reluctor wheel damage |
| - | Incorrect sensor installation |
| - | The sensor coming in contact with the reluctor wheel |
| - | Excessive air gap between the reluctor wheel and the sensor magnet |
| - | A cracked or damaged sensor |
| - | Foreign material passing between the sensor and the reluctor wheel |
| • | This DTC will set with an intermittent failure on the ignition 1 voltage circuit, the CMP sensor signal circuit, or the low reference circuit. A hard failure of any one of these circuits should set DTC P0342 or P0343. |
| • | The CMP sensor low reference circuit is shared with the mass air flow (MAF) sensor, and the engine coolant temperature (ECT) sensor. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
The Diagnostic System Check prompts the technician to complete some basic checks and store the Freeze Frame data on the scan tool, if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.
-
This step determines whether the DTC P0341 is the result of a hard failure or an intermittent condition.
-
This step tests the CMP sensor input circuit.
Step | Action | Values | Yes | No | ||||
|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module Connector End Views or Engine Controls Connector End Views | ||||||||
Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | ||||||
Did the DTC fail this ignition? | -- | Go to Step 3 | Go to Diagnostic Aids | |||||
3 |
Did the test lamp illuminate? | -- | Go to Step 4 | Go to Step 7 | ||||
4 |
Is the voltage near the specified value? | 12 V | Go to Step 5 | Go to Step 8 | ||||
Is the voltage near the specified value? | 12 V | Go to Step 10 | Go to Step 6 | |||||
6 |
Did you find and repair a condition? | -- | Go to Step 14 | Go to Step 9 | ||||
7 |
Did you complete the repair? | -- | Go to Step 14 | -- | ||||
8 |
Did you complete the repair? | -- | Go to Step 14 | -- | ||||
9 |
Did you find and correct a condition? | -- | Go to Step 14 | Go to Step 13 | ||||
10 |
Did you find and correct a condition? | -- | Go to Step 14 | Go to Step 11 | ||||
11 |
Did you find and correct a condition? | -- | Go to Step 14 | Go to Step 12 | ||||
12 | Replace the CMP sensor. Refer to Camshaft Position Sensor Replacement. Did you complete the replacement? | -- | Go to Step 14 | -- | ||||
13 |
Did you complete the replacement? | -- | Go to Step 14 | -- | ||||
14 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 15 | ||||
15 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK | |||||
