The camshaft position (CMP) sensor correlates the crankshaft to camshaft position so that the engine control module (ECM) can determine which cylinder is ready to be fueled by an injector. As the camshaft rotates, the reluctor wheel interrupts a magnetic field produced by a magnet within the sensor and sends a signal to the ECM through the signal circuit. The CMP sensor also determines which cylinder is misfiring. The circuits between the CMP sensor and the ECM consists of the following:
• | A ground circuit |
• | A CMP signal circuit |
If the ECM detects that a minimum number of CMP re-syncs has not occurred, the ECM fuels the engine by using the alternating synchronous double fire (ASDF) method and DTC P0341 sets.
This diagnostic procedure supports the following DTC:
DTC P0341 Camshaft Position (CMP) Sensor Performance
• | The engine is running. |
• | DTC P0341 runs continuously when the above condition is met. |
The ECM detects an incorrect number of CMP re-syncs has occurred 40 out of 200 tests.
• | 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 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. |
Step | Action | Yes | No | ||||||||||
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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 - Engine Controls? | Go to Step 2 | |||||||||||
2 |
Did DTC P0341 fail this ignition? | Go to Step 4 | Go to Step 3 | ||||||||||
3 |
Did the DTC fail this ignition? | Go to Step 4 | Go to Intermittent Conditions | ||||||||||
4 |
Did you find and correct the condition? | Go to Step 11 | Go to Step 5 | ||||||||||
5 |
Did you find and correct the condition? | Go to Step 11 | Go to Step 6 | ||||||||||
6 | Test for an intermittent and for a for 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 11 | Go to Step 7 | ||||||||||
7 | Test for an intermittent and for a for poor connection at the CMP connector. 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 11 | Go to Step 8 | ||||||||||
8 |
Did you find and correct the condition? | Go to Step 11 | Go to Step 9 | ||||||||||
9 |
Important: If the reluctor wheel is damaged, replace the CMP sensor. Inspect the reluctor wheel for the following conditions:
Refer to Camshaft Gear Replacement in Engine Mechanical - 2.0L (L34 GMDAT). Did you find and correct the condition? | Go to Step 11 | Go to Step 10 | ||||||||||
10 | Replace the CMP sensor. Refer to Camshaft Position Sensor Replacement . Did you complete the replacement? | Go to Step 11 | -- | ||||||||||
11 |
Did the DTC fail this ignition? | Go to Step 2 | Go to Step 12 | ||||||||||
12 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | System OK |