GM Service Manual Online
For 1990-2009 cars only

Circuit Description

Each camshaft is equipped with a camshaft position (CMP) sensor that the engine control module (ECM) monitors. The CMP sensor is a hall effect switch that works in conjunction with a 4X reluctor wheel. The reluctor wheels are mounted to the camshaft position actuators that are mounted to the end of the camshafts. The ECM uses the CMP sensor signals in order to determine the position of the camshafts.

The ECM supplies 5 volts to the CMP sensors on the 5-volt reference circuits, and supplies a ground on the low reference circuits. The CMP sensors provide a signal to the ECM on the signal circuits. If the ECM detects the CMP signal voltage is less than a predetermined voltage, within a certain number of crankshaft revolutions, this DTC sets.

DTC Descriptors

This diagnostic procedure supports the following DTCs:

    • DTC P0342 Intake Camshaft Position (CMP) Sensor Circuit Low Voltage Bank 1
    • DTC P0347 Intake Camshaft Position (CMP) Sensor Circuit Low Voltage Bank 2
    • DTC P0367 Exhaust Camshaft Position (CMP) Sensor Circuit Low Voltage Bank 1
    • DTC P0392 Exhaust Camshaft Position (CMP) Sensor Circuit Low Voltage Bank 2

Conditions for Running the DTC

    • The engine is operating for more than 1 second.
    • The engine speed is less than 2520 RPM.
    • DTCs P0342, P0347, P0367, P0392 run continuously once the engine is operating for more than 1 second.

Conditions for Setting the DTC

The CMP sensor signal voltage is always low and the ECM detects no pulses from the CMP sensor for more than 4 seconds.

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 4 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

    • Use the J 35616-A/BT-8637 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector.
    • The lower connector of the ECM is connector C1 and the upper connector of the ECM is connector C2. Refer to Engine Controls Component Views .
    • For an intermittent condition, refer to Intermittent Conditions .

Test Description

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

  1. This step determines that the condition is present.

  2. This step tests the signal circuit of the CMP sensor. This circuit is pulled-up to about 5 volts.

  3. This step tests for high resistance in the low reference circuit of the CMP sensors. The ECM must be completely powered down to obtain an accurate resistance reading. It may take up to 30 minutes for the ECM to power down after the ignition key is removed. Removal of the ECM/TCM fuse allows the ECM to power down completely.

Step

Action

Values

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 - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Turn ON the ignition, with the engine OFF.
  2. Clear the diagnostic trouble codes (DTCs) with a scan tool.
  3. Start the engine.
  4. Observe the DTC information with a scan tool.

Does the scan tool indicate that DTC P0342, P0347, P0367, or P0392 failed 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 Diagnostic Aids

4

  1. Turn OFF the ignition.
  2. Disconnect the appropriate camshaft position (CMP) sensor connector.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage between the signal circuit of the CMP sensor and the engine control module (ECM) housing with a DMM.

Is the voltage within the specified range?

4.5-5.5 V

Go to Step 5

Go to Step 6

5

  1. Turn OFF the ignition.
  2. Remove the ECM/TCM fuse from the underhood electrical center.
  3. Notice: Do NOT use a test lamp to test the continuity of the circuit. Damage to the control module may occur due to excessive current draw.

  4. Measure the resistance between the low reference circuit of the CMP sensor and the ECM housing with a DMM.

Is the resistance less than the specified value?

5 ohms

Go to Step 8

Go to Step 7

6

Test the signal circuit of the CMP sensor for a short to ground. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 12

Go to Step 9

7

Important: The low reference circuits are shared with other components. The low reference circuits are connected internally and externally of the controller. Other sensors that share the low reference circuit may also have DTCs set. Review the electrical schematic and diagnose the shared circuits and sensors.

Test the low reference circuit of the CMP sensors for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 12

Go to Step 9

8

Test for an intermittent and for a poor connection at CMP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

--

Go to Step 12

Go to Step 10

9

Test for an intermittent and for a poor connection at the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

--

Go to Step 12

Go to Step 11

10

Replace the CMP sensor. Refer to one of the following procedures:

Did you complete the replacement?

--

Go to Step 12

--

11

Replace the ECM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

--

Go to Step 12

--

12

  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 13

13

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

System OK