GM Service Manual Online
For 1990-2009 cars only

Object Number: 52877  Size: SF
Engine Controls Components
Ignition Controls
OBD II Symbol Description Notice
Engine Controls Connector End Views
Handling ESD Sensitive Parts Notice

Circuit Description

The camshaft position (CMP) sensor indicates the camshaft position so the powertrain control module (PCM) can determine which cylinder is misfiring when a misfire is present. Whenever the PCM receives an intermittent signal from the CMP, then the CMP actrivity counter will increment. In order to set a DTC, the PCM must see a minimum number of resyncs within a maximum time.

Conditions for Setting the DTC

    • The Engine is running.
    • The Cam Sensor activity counter does not increment.

Action Taken When the DTC Sets

    • The malfunction indicator lamp (MIL) will illuminate.
    • The PCM will record the operating conditions at the time that the diagnostic fails. The Freeze Frame and Failure Records buffers will store this information.
    • A history DTC stores.

Conditions for Clearing the MIL/DTC

    • The malfunction indicator lamp (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

    • A poor connection, rubbed through wire insulation, or a wire that is broken inside the insulation may cause an intermittent problem.
    • Thoroughly check any circuitry, that is suspected as causing the intermittent complaint, proper mating, broken locks, improperly formed or damaged terminals, or physical damage to the wiring harness.
    • Whenever the PCM sees less than 15 resyncs in 256 seconds, the counter resets to 0. Anytime a poor connection is present, the cam sensor reference activity counter stops incrementing and the cam sensor resync counter starts to increment.

Test Description

Number(s) below refer to the step number(s) on the Diagnostic Table.

  1. The Powertrain OBD System Check prompts the technician to complete some basic checks and store the freeze frame and failure records data on the scan tool if applicable. This creates an electronic copy of the data taken when the malfunction occurred. The information is then stored on the scan tool for later reference.

  2. This step determines if the DTC P0342 is the result of a hard malfunction or an intermittent condition.

  3. Determines if the voltage is available to the CMP sensor through the PCM.

  4. Determines if voltage is available to the CMP sensor through the PCM.

  5. This step checks for a signal from the CMP sensor. It is necessary to supply B+ to the ignition positive #2 terminal in order for the CMP sensor to have B+ supplied to it. While cranking the engine, the CMP sensor will send a B+ signal and then a ground signal as the reluctor passes the sensor.

  6. Replacement PCMs must be reprogrammed and the crankshaft position system variation procedure must be performed. Refer to the latest Techline information for PCM reprogramming and also refer to the Powertrain Control Module (PCM) for the Crankshaft Position System Variation Procedure.

DTC P0342-Camshaft Position (CMP) Sensor Circuit Low Input

Step

Action

Value(s)

Yes

No

1

Was the Powertrain On-Board Diagnostic (OBD) System Check performed?

--

Go to Step 2

Go to

Powertrain On Board Diagnostic (OBD) System Check

2

  1. With the engine running.
  2. Install a scan tool.

Is the CMP Reference Activity counter incrementing?

--

Go to Step 3

Go to Step 4

3

  1. Turn the ignition switch ON, with the engine OFF.
  2. Review the Freeze Frame data and note the parameters.
  3. Operate the vehicle within the Freeze Frame conditions and Conditions For Setting The DTC as noted.

Is the CMP Reference Activity Counter incrementing?

--

Go to Step 16

Go to Step 4

4

  1. Turn the ignition switch ON, with the engine OFF.
  2. Disconnect the Camshaft Position (CMP) sensor electrical connector.
  3. Connect a test light to ground, probe the CMP sensor positive voltage feed terminal.

Did the test light illuminate?

--

Go to Step 5

Go to Step 6

5

Connect a test light to B+, probe the CMP ground terminal.

Did the test light illuminate?

--

Go to Step 7

Go to Step 8

6

Check for a poor connection or an open in the CMP B+ feed circuit and repair as necessary.

Was a repair necessary?

--

Go to Step 16

Go to Step 15

7

  1. Turn the ignition switch OFF.
  2. Reconnect the CMP sensor electrical connector.
  3. Disconnect the specified PCM electrical connector.
  4. Install a jumper wire to B+ in the ignition #2 terminal of the PCM electrical connector.
  5. With a DVM connected to ground, probe the CMP signal terminal at the PCM electrical connector.
  6. Crank the engine.

Does the DVM display a voltage varying between the specified values?

C1

0V-B+

Go to Step 15

Go to Step 9

8

Check for a poor connection or an open in the CMP ground circuit and repair as necessary.

Was a repair necessary?

--

Go to Step 16

Go to Step 15

9

Did the DVM display a steady voltage of the specified value?

B+

Go to Step 10

Go to Step 11

10

Check the CMP signal circuit for a short to B+ and repair as necessary.

Was a repair necessary?

--

Go to Step 16

Go to Step 14

11

  1. Disconnect the CMP sensor electrical connector.
  2. Connect the DVM to B+, probe the CMP signal circuit.

Did the DVM display a voltage greater than the specified value?

0.5V

Go to Step 12

Go to Step 13

12

Repair the short to ground in the CMP signal circuit.

Is the action complete?

--

Go to Step 16

--

13

Check for a poor connection or an open in the CMP signal circuit and repair as necessary.

Was a repair necessary?

--

Go to Step 16

Go to Step 14

14

Replace the Camshaft Position (CMP) sensor.

Is the action complete?

--

Go to Step 16

--

15

Replace the PCM.

Is the action complete?

--

Go to Step 16

--

16

  1. Using the scan tool, clear the DTCs.
  2. Start the engine and idle at normal operating temperature.
  3. Operate the vehicle within the conditions for setting this DTC as specified in the supporting text.

Does the scan tool indicate that this diagnostic has ran and passed?

--

Go to Step 17

Go to Step 2

17

Check if any additional DTCs are set.

Are any DTCs displayed that have not been diagnosed?

--

Go to applicable DTC table

System OK