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For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2004 🢒 Malibu 🢒 Vehicle Control Systems 🢒 Vehicle DTC Information 🢒 DTC P0340

Circuit Description

The camshaft position (CMP) sensor consists of a 12-volt reference circuit, a low reference circuit, and a signal circuit. The powertrain control module (PCM) constantly monitors the number of pulses on the CMP signal circuit. If the PCM receives an incorrect number of pulses on the CMP signal circuit, DTC P0340 will set.

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC

The camshaft position (CMP) sensor reference pulse is not detected during every engine revolution.

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 3 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

The following conditions may cause this DTC to set:

    •  Incorrect harness routing near secondary ignition components
    •  Ignition coil arcing to wiring harness or IC module -- Inspect the ignition coils for cracks, for carbon tracking, or for other signs of damage.
    • Camshaft reluctor wheel damage
    • The sensor coming in contact with the reluctor wheel
    • Foreign material passing between the sensor and the reluctor wheel
    • Excessive camshaft end-play

If the condition is intermittent, refer to Intermittent Conditions .

Step

Action

Values

Yes

No

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module Connector End Views

1

Did you perform the Diagnostic System Check-Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

Attempt to start the engine.

Does the engine start and run?

--

Go to Step 4

Go to Step 3

3

Are DTCs P0335 and P0340 set?

--

Go to Step 10

Go to Step 4

4
  1. Start the engine.
  2. Observe the CMP sensor signal present parameter with a scan tool.

Does the scan tool indicate the CMP sensor signal is present?

--

Go to Step 5

Go to Step 6

5
  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 6

Go to Diagnostic Aids

6
  1. Turn OFF the ignition.
  2. Disconnect the CMP sensor connector.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the 12-volt reference circuit of the CMP sensor harness connector with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors in Wiring Systems.

Does the test lamp illuminate?

--

Go to Step 7

Go to Step 11

7
  1. Turn OFF the ignition.
  2. Jumper the CMP circuits from the CMP sensor to the CMP sensor harness connector. Refer to Using Connector Test Adapters in Wiring Systems.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the Voltage Drop from the low reference circuit of the CMP sensor to a good ground with a DMM. Refer to Circuit Testing in Wiring Systems.

Is the voltage more than the specified value?

0.2 V

Go to Step 12

Go to Step 8

8
  1. Remove the jumpers from the CMP circuits.
  2. Start the engine.
  3. Observe the CMP sensor signal on the scan tool.
  4. Momentarily and repeatedly probe the signal circuit of the CMP sensor with a test lamp that is connected to battery voltage.

Does the CMP sensor signal change when the test lamp contacts the signal circuit?

--

Go to Step 15

Go to Step 9

9
  1. Turn ON the ignition, with the engine OFF.
  2. Probe the signal circuit of the CMP sensor harness connector with a test lamp connected to a good ground. Refer to Probing Electrical Connectors in Wiring Systems.

Does the test lamp illuminate?

--

Go to Step 14

Go to Step 13

10
  1. Disconnect the CMP sensor.
  2. Test the CMP 12-volt reference circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 21

Go to Step 15

11

Test the CMP 12-volt reference circuit between the CMP sensor and the PCM for an open or for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 21

Go to Step 16

12

Test the CMP Low reference circuit between the CMP sensor and the PCM for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 21

Go to Step 16

13

Important: Disconnecting the PCM may remove the short from the circuit.

Test the CMP signal circuit between the CMP sensor and the PCM for a open or for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 21

Go to Step 16

14

Important: Disconnecting the PCM may remove the short from the circuit.

Test the CMP signal circuit between the CMP sensor and the PCM for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 21

Go to Step 16

15

Test for an intermittent and for poor connections at the CMP harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 21

Go to Step 17

16

Test for an intermittent and for poor connections at the PCM harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 21

Go to Step 20

17
  1. Remove the CMP sensor. Refer to Camshaft Position Sensor Replacement .
  2. Visually inspect the CMP sensor for the following conditions:
    3. • Physical damage
    • Loose or improper installation

Did you find and correct the condition?

--

Go to Step 21

Go to Step 18

18
  1. Visually inspect the CMP sensor reluctor wheel for damage.
  2. If the CMP reluctor wheel is damaged, refer to Camshaft and Bearings Cleaning and Inspection in Engine Mechanical.

Did you find and correct the condition?

--

Go to Step 21

Go to Step 19

19

Replace CMP sensor. Refer to Camshaft Position Sensor Replacement .

Did you complete the replacement?

--

Go to Step 21

--

20

Replace the PCM. Refer to Powertrain Control Module Replacement .

Did you complete the replacement?

--

Go to Step 21

--

21
  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 22

22

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 in Vehicle DTC Information

System OK