Circuit Description
The camshaft position (CMP) sensor works in conjunction with the 1X reluctor trigger wheel on the front of the camshaft gear. The engine control module (ECM) provides a 12-volt reference to the CMP sensor, as well as a low reference and a signal circuit. As the camshaft gear rotates, the reluctor trigger wheel interrupts a magnetic field produced by a magnet within the sensor. The CMP sensor internal circuitry detects this interruption of the magnetic field and produces a signal, which the ECM reads. The 1X signal produced by the CMP sensor is used by the ECM to determine if the cylinder at the top dead center (TDC) is on the firing stroke or the exhaust stroke. The ECM can determine TDC for all cylinders by using the crankshaft position (CKP) sensor 24X signal. The engine will start without a CMP sensor signal as long as the ECM receives the CKP sensor 24X signal. If the 1X signal is not received by the ECM, a slightly longer cranking time may be experienced. The ECM will attempt synchronization and looks for an increase in engine speed, indicating that the engine is running. If the ECM does not detect an increase in engine speed, the ECM assumes that it incorrectly synchronized to the exhaust stroke, and then will synchronize to the opposite cam position. If the ECM detects that the ratio of the CMP sensor to CKP sensor trigger pulses are missing or incorrect, DTC P0341 will set.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0341 Camshaft Position (CMP) Sensor Performance
Conditions for Running the DTC
| • | The engine is cranking, or the engine is running. |
| • | DTCs P0335, P0336, and P0340 are not set. |
| • | DTC P0341 runs continuously when the above conditions are met. |
Conditions for Setting the DTC
The ECM detects a missing or a noisy CMP sensor signal for 100 engine cycles.
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The control module stores the information in the Freeze Frame/Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the 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. |
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 circuits.
-
Damage to the face of the sensor could indicate material passing between the CMP sensor and the reluctor wheel. This condition could cause this DTC to set. Damage to the reluctor wheel would affect the CMP sensor output signal.
Step | Action | Yes | No | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module Connector End Views or Engine Controls Connector End Views | |||||||||||||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | ||||||||||
2 | Is DTC P0340 also set? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | Go to Step 3 | ||||||||||
3 |
Did the DTC fail this ignition? | Go to Step 4 | Go to Intermittent Conditions | ||||||||||
Did you find and correct the condition? | Go to Step 9 | Go to Step 5 | |||||||||||
5 |
Did you find and correct the condition? | Go to Step 10 | Go to Step 6 | ||||||||||
6 | Test for an intermittent and for a poor connection at the engine control module (ECM). 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 10 | Go to Step 7 | ||||||||||
Did you find and correct the condition? | Go to Step 10 | Go to Step 8 | |||||||||||
8 | Visually inspect the CMP sensor reluctor ring or camshaft gear for the following conditions:
Did you find and correct the condition? | Go to Step 10 | Go to Step 9 | ||||||||||
9 | Replace the CMP sensor. Refer to Camshaft Position Sensor Replacement . Did you complete the replacement? | Go to Step 10 | -- | ||||||||||
10 |
Did the DTC fail this ignition? | Go to Step 2 | Go to Step 11 | ||||||||||
11 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | System OK | ||||||||||
