GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    •  Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC P0341: Intake Camshaft Position (CMP) Sensor Performance Bank 1

DTC P0342: Intake Camshaft Position (CMP) Sensor Circuit Low Voltage Bank 1

DTC P0343: Intake Camshaft Position (CMP) Sensor Circuit High Voltage Bank 1

DTC P0346: Intake Camshaft Position (CMP) Sensor Performance Bank 2

DTC P0347: Intake Camshaft Position (CMP) Sensor Circuit Low Voltage Bank 2

DTC P0348: Intake Camshaft Position (CMP) Sensor Circuit High Voltage Bank 2

DTC P0366: Exhaust Camshaft Position (CMP) Sensor Performance Bank 1

DTC P0367: Exhaust Camshaft Position (CMP) Sensor Circuit Low Voltage Bank 1

DTC P0368: Exhaust Camshaft Position (CMP) Sensor Circuit High Voltage Bank 1

DTC P0391: Exhaust Camshaft Position (CMP) Sensor Performance Bank  2

DTC P0392: Exhaust Camshaft Position (CMP) Sensor Circuit Low Voltage Bank 2

DTC P0393: Exhaust Camshaft Position (CMP) Sensor Circuit High Voltage Bank 2

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

CMP Sensor 5-Volt Reference

P0343, P0348, P0368, P0393, P0652, P2122, P2138

P0343, P0348, P0368, P0393

P0653, P2123, P2138

P0341, P0346, P0366, P0391, P0652, P0653, P2138

CMP Sensor Signal Intake Bank 1

P0342

P0343

P0343

P0341

CMP Sensor Signal Intake Bank 2

P0347

P0348

P0348

P0346

CMP Sensor Signal Exhaust Bank 1

P0367

P0368

P0368

P0366

CMP Sensor Signal Exhaust Bank 2

P0392

P0393

P0393

P0391

Low Reference

--

P0343, P0348, P0368, P0393

--

P0341, P0346, P0366, P0391

Circuit/System 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 extra or missing CMP sensor signal transitions, or a signal voltage that is more or less than the predetermined range, within a certain number of crankshaft revolutions, one of these DTCs sets.

Conditions for Running the DTC

    • The engine is operating for more than 1 second.
    •  The DTCs run continuously once the above condition is met.

Conditions for Setting the DTC

P0341, P0346, P0366, P0391

    • The ECM detects a signal from the CMP sensor, but the number of pulses are less than or more than what is expected for one crankshaft revolution.
        OR
    • The CMP sensor does NOT correlate to the crankshaft position.
    • Either condition must exist for more than 4 seconds, or cumulative of 50 seconds.

P0342, P0347, P0367, P0392

The CMP sensor signal voltage is always low and the ECM detects no pulses from the CMP sensor for more than 4 seconds, or cumulative of 50 seconds.

P0343, P0348, P0368, P0393

The CMP sensor signal voltage is always high and the ECM detects no pulses from the CMP sensor for more than 4 seconds or cumulative of 50 seconds.

Action Taken When the DTC Sets

DTCs P0341, P0342, P0343, P0346, P0347, P0348, P0366, P0367, P0368, P0391, P0392, and P0393 are Type B DTCs.

Conditions for Clearing the DTC

DTCs P0341, P0342, P0343, P0346, P0347, P0348, P0366, P0367, P0368, P0391, P0392, and P0393 are Type B DTCs.

Diagnostic Aids

    • Test the current out-put of the signal circuit if you suspect high resistance in the circuit. The current out-put should be greater than 1 mA when measured on the 400 mA scale.
    • The following conditions can also set the DTC:
      • Physical damage to the CMP sensor or the reluctor wheel
      • Excessive play or looseness of the CMP sensor or the reluctor wheel
      •  Improper installation of the CMP sensor or the reluctor wheel
      • Foreign material passing between the CMP sensor and the reluctor wheel
      • Excessive air gap between the CMP sensor and the reluctor wheel

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

    •  Engine Control Module Connector End Views
    •  Engine Controls Connector End Views

Description and Operation

Electronic Ignition (EI) System Description

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

    •  Scan Tool Data List
    •  Scan Tool Data Definitions
    •  Scan Tool Output Controls

Circuit/System Verification

  1. Ignition ON, observe the DTC information with a scan tool. DTC P0652 or P0653 should not be set.
  2. If a DTC is set, refer to DTC P0652 or P0653 .
  3. Engine idling, observe the DTC information with a scan tool. DTCs P0341, P0342, P0343, P0346, P0347, P0348, P0366, P0367, P0368, P0391, P0392, and P0393 should not set.
  4. If the vehicle passes the Circuit/System Verification test, then operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records List.

Circuit/System Testing

  1. Ignition OFF, remove the fuse that supplies B+ to terminal C2-56 of the ECM.
  2. Disconnect the harness connector at the appropriate CMP sensor.
  3. Important: The control module or the sensor may be damaged if the circuit is shorted to B+ voltage.

  4. Test for 5 ohms or less between the low reference circuit terminal 1 and ground.
  5. If greater than 5 ohms, test the low reference circuit for an open/high resistance or for a short to voltage. If the circuit/connections test normal, replace the ECM.
  6. Install the fuse that supplies B+ to terminal C2-56 of the ECM.
  7. Ignition ON, test for greater than 4.8 volts between the 5 volt reference circuit terminal 3 and ground.
  8. If less than the specified value, test the 5 volt reference circuit for an open/high resistance. If the circuits/connections test normal, replace the ECM.
  9. Test for 4.8-5.2 volts between the signal circuit terminal 2 and ground.
  10. If the voltage is greater than specified range, test for a short to voltage in the signal circuit. If circuit/connections test normal, replace the ECM.

    Important: The signal circuit voltage can be within the specified range with a high resistance in the circuit. If this condition is suspected, refer to Diagnostic Aids.

    If the voltage is less than the specified range, test for a short to ground or an open/high resistance in the signal circuit. If circuit/connections test normal, replace the ECM.
  11. If all circuits/connections test normal, replace the CMP sensor.

Repair Instructions

Perform the Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Camshaft Position Sensor Replacement - Bank 2 (Left Side) Exhaust
    •  Camshaft Position Sensor Replacement - Bank 2 (Left Side) Intake
    •  Camshaft Position Sensor Replacement - Bank 1 (Right Side) Exhaust
    •  Camshaft Position Sensor Replacement - Bank 1 (Right Side) Intake
    •  Control Module References for engine control module replacement, setup, and programming