GM Service Manual Online
For 1990-2009 cars only

Circuit Description

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 circuits are directly connected to the ECM. 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.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0341 Camshaft Position (CMP) Sensor Performance

Conditions for Running the DTC

    • The engine is running
    • DTC P0341 runs continuously when the above condition is met.

Conditions for Setting the DTC

The ECM detects an incorrect number of CMP re-syncs has occurred 40 out of 200 tests.

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.

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 - Engine Controls?

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

  1. Start the engine
  2. Observe the DTC Information with a scan tool.

Did DTC P0341 fail this ignition?

Go to Step 4

Go to Step 3

3

  1. Observe the Freeze Frame/Failure Records for this DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

Did the DTC fail this ignition?

Go to Step 4

Go to Intermittent Conditions

4

  1. Turn OFF the ignition.
  2. Inspect the camshaft position (CMP) sensor circuits for the following conditions:
  3. • Routed too close to other wiring or components
    • Routed too close to after market add on electrical equipment
    • Routed too close to solenoids, relays, and motors
    • Electromagnetic interference in the CMP sensor circuits

Did you find and correct the condition?

Go to Step 11

Go to Step 5

5

Remove the engine cover. Refer to Engine Cover Replacement

Test the CMP sensor circuits for an intermittent condition. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

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 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

  1. Remove the CMP sensor. Refer to Camshaft Position Sensor Replacement .
  2. Inspect the CMP sensor for the following conditions:
  3. • Physical damage
    • Excessive play or looseness
    • Improper installation
    • Foreign material passing between the CMP sensor and the reluctor wheel
    • Excessive air gap between the CMP sensor and the reluctor wheel

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:

    • Physical damage
    • Improper installation
    • Excessive end play or looseness

Refer to Camshaft Gear Replacement in Engine Mechanical.

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

  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

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?

Go to Diagnostic Trouble Code (DTC) List

System OK