Circuit Description
The camshaft position (CMP) sensor works in conjunction with a 1 X reluctor wheel on the camshaft. The powertrain control module (PCM) provides a 12-volt reference to the CMP sensor as well as a low reference and a signal circuit.
As the camshaft rotates, the reluctor wheel interrupts a magnetic field produced by a magnet within the sensor. The sensors internal circuitry detects this and produces a signal which the PCM reads. The PCM uses this 1 X signal in combination with the crankshaft position (CKP) sensor signal in order to determine the CKP and stroke.
The CMP sensor 1 X signal is used by the PCM to determine if the cylinder at top dead center (TDC) is on the firing stroke or the exhaust stroke. The PCM can determine TDC for all cylinders by using the CKP sensor signal alone. Observe that as long as the PCM receives the CKP sensor signal, the engine will start without a CMP signal. A slightly longer cranking time may be a symptom of this condition. The system attempts synchronization and looks for an increase in engine speed indicating that the engine started. If the PCM does not detect an increase in engine speed, the PCM assumes that the PCM incorrectly synchronized to the exhaust stroke and re-syncs to the opposite cam position. If the PCM detects that a CMP to CKP mis-match has occurred, this DTC sets.
DTC Descriptors
This diagnostic procedure supports the following DTC.
DTC P0341 Camshaft Position (CMP) Sensor Performance
Conditions for Running the DTC
| • | The engine is operating. |
| • | DTC P0341 runs continuously once the engine is operating. |
Conditions for Setting the DTC
The PCM detects that a CMP to CKP mis-match has occurred.
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 ring damage |
| • | The sensor coming in contact with the reluctor ring |
| • | Foreign material passing between the sensor and the reluctor ring |
| • | Excessive camshaft end-play |
| • | Wiring routed too close to secondary ignition components |
If you suspect the condition is intermittent, refer to Intermittent Conditions .
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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This step inspects for electromagnetic interference (EMI) on the CMP sensor circuits.
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Damage to the face of the sensor could indicate foreign material passing between the CMP sensor and the reluctor wheel. This condition would cause this DTC to set. Damage to the reluctor wheel would affect the CMP sensor output.
Step | Action | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Powertrain Control Module Connector End Views or Engine Controls Connector End Views | |||||||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | Go to Step 2 | |||||||
2 |
Important: If DTC P0342 or P0343 are set diagnose those DTCs first. Refer to DTC P0342 and DTC P0343 Did the DTC fail this ignition? | Go to Step 3 | Go to Diagnostic Aids | ||||||
Did you find and correct the condition? | Go to Step 9 | Go to Step 4 | |||||||
4 | Test for an intermittent and for a poor connection at the CMP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 9 | Go to Step 5 | ||||||
5 | Test for an intermittent and for a poor connection at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 9 | Go to Step 6 | ||||||
Did you find and correct the condition? | Go to Step 9 | Go to Step 7 | |||||||
7 |
Did you find and correct the condition? | Go to Step 9 | Go to Step 8 | ||||||
8 | Replace the CMP 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 | Observe the Capture Info with a scan tool. Are there any DTC's that have not been diagnosed? | System OK | |||||||
