GM Service Manual Online
For 1990-2009 cars only

Object Number: 621245  Size: SF
Engine Controls Components
Power, Ground, KS, CMP, CKP, Coils, and ICM
OBD II Symbol Description Notice
Powertrain Control Module Connector End Views
Handling ESD Sensitive Parts Notice

Circuit Description

The camshaft position (CMP) sensor correlates the crankshaft to camshaft position so that the Powertrain Control Module (PCM) can determine which cylinder is ready to be fueled by the injector. The CMP sensor also determines which cylinder is misfiring when a misfire is present. If the PCM receives an intermittent signal from the CMP, the CMP Resync Counter will increment. When the PCM cannot use the information from the CMP sensor, a DTC is set and the PCM will fuel the engine using the Alternating Synchronous Double Fire (ASDF) method.

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC

The PCM senses more than 15 CMP sensor resyncs in 256 seconds (4 min. 16 sec.).

Action Taken When the DTC Sets

    • The malfunction indicator lamp (MIL) will illuminate after 2 consecutive ignition cycles in which the diagnostic runs with the fault active.
    • The PCM records the operating conditions at the time when the diagnostic fails. This information stores in the Freeze Frame and Failure Records buffers.
    • A history DTC stores.
    • The coolant fan turns on.

Conditions for Clearing the MIL/DTC

    • The MIL will turn off after 3 consecutive ignition cycles in which the diagnostic runs without a fault.
    • A history DTC will clear after 40 consecutive warm up cycles without a fault.
    • Use a scan tool to clear the DTCs.

Diagnostic Aids

    • If the PCM senses less than 15 resyncs in 256 seconds, the counter is reset to 0. Anytime a poor connection is present, the CMP Activity counter will stop incrementing and the CMP Resync counter will increment.
    • An intermittent problem may be caused by the following items:
       - The CMP sensor. Substitute a known good part. Operate the vehicle within the Failure Records and the Conditions for Running the DTC as specified in the supporting text. If the condition still exists, remove the substitute part.
       - The PCM. Substitute a known good part. Operate the vehicle within the Failure Records and the Conditions for Running the DTC as specified in the supporting text. If the condition still exists, remove the substitute part.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step determines if DTC P0341 is a hard malfunction or an intermittent condition.

  2. The counter should stop incrementing with the sensor disconnected and set a DTC P0342. If the counter stills increments, the PCM is malfunctioning.

  3. The replacement PCM must be programmed and the Crankshaft Position System Variation Learn procedure must be performed.

DTC P0341 - Camshaft Position (CMP) Sensor Circuit Performance

Step

Action

Value(s)

Yes

No

1

Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2

Operate the vehicle within the Failure Records conditions and the Conditions for Running the DTC as specified in the supporting text.

Does the CMP Resync counter increment?

--

Go to Step 3

Go to Step 4

3

Caution: Avoid contact with moving parts and hot surfaces while working around a running engine in order to prevent physical injury.

Disconnect the camshaft position (CMP) sensor connector.

Did the CMP Resync counter stop incrementing?

--

Go to Step 5

Go to Step 8

4

Caution: Avoid contact with moving parts and hot surfaces while working around a running engine in order to prevent physical injury.

Perform the intermittent test at the CMP sensor with the engine running. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems .

Did the CMP Resync counter start to increment?

--

Go to Step 5

Go to Step 6

5

  1. Turn off the ignition.
  2. Inspect for a poor connection at the CMP sensor.
  3. If a problem is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 10

Go to Step 7

6

Inspect the CMP sensor for a poor connection at the PCM

Did you find and correct the condition?

--

Go to Step 10

Go to Diagnostic Aids

7

  1. Disconnect the PCM connector.
  2. Inspect the CMP for a poor connection.
  3. If a problem is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 10

--

8

Important:: The replacement PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming .

Replace the PCM. Refer to Powertrain Control Module Replacement .

Did you complete the repair?

--

Go to Step 10

Go to Step 9

9

Replace the CMP sensor. Refer to Camshaft Position Sensor Replacement .

Did you complete the repair?

--

Go to Step 10

--

10

  1. Use the scan tool to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

--

Go to Step 2

System OK