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 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, then 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 by using the alternating synchronous double fire (ASDF) method.

Conditions for Setting the DTC

    • The engine is running.
    • The CMP Active Counter is not incrementing.

Action Taken When the DTC Sets

    • The malfunction indicator lamp (MIL) illuminates.
    • 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 three 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.
    • The MIL/DTCs can be cleared by using the scan tool.

Diagnostic Aids

    • An Intermittent problem may be caused by the following conditions:
       - Poor electrical connection
       - Rubbed-through wire insulation
       - Broken wire inside the insulation
    • Thoroughly check any suspected circuitry for the following conditions:
       - Backed-out terminals
       - Improper mating
       - Broken locks
       - Improperly formed connectors
       - Damaged terminals
       - Poor terminal to wiring connections
       - Physical damage to the wiring harness

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 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 ground 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. The replacement PCM must be programmed and the crankshaft position system variation procedure must be preformed. Refer to the latest Techline procedure for PCM reprogramming and also refer to Powertrain Control Module (PCM) 2.4L, Powertrain Control Module (PCM) 2.2L 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

2.4L

Powertrain On Board Diagnostic (OBD) System Check

2.2L

2

  1. Turn the ignition switch ON, with the engine running.
  2. Install a scan tool.

Is the CMP Active 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 Active 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. Connect a DVM to ground, probe the CMP signal terminal at the PCM 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?

0.5 V

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