GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The camshaft position (CMP) sensor is a 1X sensor. It provides one digital ON/OFF signal to the powertrain control module (PCM) per revolution of the camshaft. This information is used by the PCM to determine the position of the valve train relative to the crankshaft position (CKP). By monitoring the CMP and the CKP signals, the PCM can accurately time the operation of the fuel injectors. The PCM supplies 12 volts to the sensor on the 12-volt reference circuit and provides a ground on the low reference circuit. The CMP sensor provides signals to the PCM on the CMP sensor signal circuit. The PCM monitors the CMP sensor for errors. If the PCM receives an incorrect signal from the CMP sensor, 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 cranking or running.
    • DTC P0341 runs continuously when the above condition is met.

Conditions for Setting the DTC

The PCM detects that less than 6 CKP sensor low resolution reference signals, generated by the PCM, have occurred for every CMP sensor signal.

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
    • Wear or damage to the timing chain or sprockets--Refer to Camshaft Timing Chain and Sprocket Cleaning and Inspection in Engine Mechanical.
    • 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.

  1. This step inspects for electromagnetic interference (EMI) on the CMP sensor circuits.

  2. 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: Engine Controls Connector End Views or Powertrain Control Module 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

  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 3

Go to Diagnostic Aids

3

  1. Visually and physically inspect all circuits going to the camshaft position (CMP) sensor for the following:
  2. • Being routed too close to secondary ignition wires or components
    • Being routed too close to after-market add-on electrical equipment
    • Being routed too close to solenoids, relays, and motors
  3. If you find incorrect routing, correct the harness routing.

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 powertrain control module (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

6

  1. Remove the CMP sensor. Refer to Camshaft Position Sensor Replacement .
  2. Visually inspect the CMP sensor for the following conditions:
  3. • Physical damage
    • Excessive wear of the sensor
    • Loose or improper installation

Did you find and correct the condition?

Go to Step 9

Go to Step 7

7

  1. Visually inspect the CMP sensor reluctor ring for damage.
  2. If the CMP reluctor ring is damaged, refer to Camshaft and Bearings Cleaning and Inspection in Engine Mechanical.

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

  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 10

10

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