DTC P0343 Camshaft Position (CMP) Sensor Circuit High Voltag
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PostPosted: Fri Nov 12, 2004 8:00 am    Post subject: DTC P0343 Camshaft Position (CMP) Sensor Circuit High Voltag Reply with quote

DTC P0343 Camshaft Position (CMP) Sensor Circuit High Voltage


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Circuit Description

The Camshaft Position sensor is mounted through the top of the engine block at the rear of the valley cover. The CMP sensor works in conjunction with a 1X reluctor wheel on the camshaft. The reluctor wheel is inside the engine immediately in front of the rear cam bearing. The PCM provides a 12 volt power supply to the CMP sensor as well as a ground and a signal circuit.

The CMP sensor determines whether a cylinder is on a firing stroke or on an exhaust stroke. As the camshaft rotates, the reluctor wheel interrupts a magnetic field produced by a magnet within the sensor. The sensors internal circuitry detects this and produces a signal which the PCM reads. The PCM uses this 1X signal in combination with the Crankshaft Position sensor 24X signal in order to determine crankshaft position and stroke. This diagnostic monitors for a loss of Camshaft Position sensor signal.

Observe that as long as the PCM receives the Crankshaft Position sensor 24X signal, the engine will start. The PCM can determine top dead center for all cylinders by using the Crankshaft Position sensor 24X signal alone. The Camshaft Position sensor 1X signal is used by the PCM to determine if the cylinder at top dead center is on the firing stroke, or the exhaust stroke. The system attempts synchronization and looks for an increase in engine speed indicating the engine started. If the PCM does not detect an increase in engine speed, the PCM assumes it incorrectly synchronized to the exhaust stroke and re-syncs to the opposite cam position. A slightly longer cranking time may be a symptom of this condition.

Conditions for Running the DTC

The engine speed is less than 4,000 RPM.

Conditions for Setting the DTC

The PCM detects the Cam signal is stuck high when the signal should be low for 5 seconds.

Action Taken When the DTC Sets
  • The PCM illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
  • The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the conditions to the Freeze Frame and updates the Failure Records.
Conditions for Clearing the MIL/DTC
  • The PCM turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
  • A last test failed, or current DTC, clears when the diagnostic runs and does not fail.
  • A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
  • Use a scan tool in order to clear the MIL and the DTC.
Diagnostic Aids

Important

  • Remove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM connector gaskets when diagnosing/replacing the PCM. Ensure that the gaskets are installed correctly. The gaskets prevent contaminant intrusion into the PCM.
  • For any test that requires probing the PCM or component harness connectors, use the connector test adapter kit. Using this kit prevents any damage to the harness connector terminals. Refer to Using Connector Test Adapters in Wiring Systems.

The following conditions may cause this DTC to set:

  • Poor connections/terminal tension at the sensor. Refer to Testing for Intermittent and Poor Connections in Wiring Systems.
  • Camshaft reluctor wheel damage
  • The sensor coming in contact with the reluctor wheel

For an intermittent, refer to Symptoms .

Test Description

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

  1. This step verifies that the fault is present.

  2. If the duty cycle is present at the PCM connector, the Camshaft Position sensor B+ reference and ground circuits are OK.

  3. This step tests the Camshaft Position sensor B+ reference circuit.

  4. This step tests the Camshaft Position sensor ground circuit.

  5. This step tests for a short to B+ on the Camshaft Position sensor signal circuit.

  6. This step tests for a short to ground on the Camshaft Position sensor signal circuit.

Step

Action

Value(s)

Yes

No

1

Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2

  1. Install a scan tool.
  2. Idle the engine.
  3. Monitor the CAM signal input - High to Low transition in the Engine Data List 1 using the scan tool.

Does the scan tool parameter increment?

--

Go to Step 3

Go to Step 4

3

  1. Turn ON the ignition with the engine OFF.
  2. Review the Freeze Frame and/or Failure Records data for this DTC and observe the parameters.
  3. Turn OFF the ignition for 15 seconds.
  4. Idle the engine.
  5. Operate the vehicle within the conditions required for this diagnostic to run, and as close to the conditions recorded in Freeze Frame/Failure Records as possible. Special operating conditions that you need to meet before the PCM will run this diagnostic, where applicable, are listed in Conditions for Setting the DTC.
  6. Select the Diagnostic Trouble Code (DTC) option, the Specific DTC option, then enter the DTC number using the scan tool.

Does the scan tool indicate that this diagnostic failed this ignition?

--

Go to Step 4

Go to Diagnostic Aids

4

  1. Disconnect both PCM connectors. Refer to PCM Replacement/Programming .
  2. Jumper the Camshaft Position sensor ground circuit at the PCM connector C1 (sensor side) to a known good ground.
  3. Jumper the Camshaft Position sensor ignition feed circuit at the PCM connector C2 (sensor side) to B+ using a fused jumper wire. Refer to Using Fused Jumper Wires in Wiring Systems.
  4. Measure the duty cycle from the Camshaft Position sensor signal circuit with the DMM.
  5. Crank the engine.

Does the DMM display a duty cycle within the specified range while cranking the engine?

45-55%

Go to Step 17

Go to Step 5

5

  1. Turn OFF the ignition.
  2. Reconnect the PCM connectors. Refer to PCM Replacement/Programming .
  3. Remove the intake manifold in order to gain access to the Camshaft Position sensor. Refer to Intake Manifold Replacement in Engine Mechanical 5.7L.
  4. Disconnect the Camshaft Position sensor electrical connector.
  5. Turn ON the ignition with the engine OFF.
  6. Measure the voltage from the Camshaft Position sensor B+ supply circuit to the battery ground with the DMM.

Does the DMM display the specified voltage?

B+

Go to Step 6

Go to Step 8

6

Measure the voltage from the Camshaft Position sensor B+ supply circuit to the Camshaft Position sensor ground circuit with the DMM.

Does the DMM display the specified voltage?

B+

Go to Step 9

Go to Step 7

7

Test for an open in the Camshaft Position sensor ground circuit. Refer to Testing for Continuity in Wiring Systems.

Did you find an open ground circuit?

--

Go to Step 13

Go to Step 17

8

Test for an open or a short to ground in the Camshaft Position sensor B+ reference circuit. Refer to Circuit Testing in Wiring Systems.

Did you find the circuit open or shorted to a ground?

--

Go to Step 12

Go to Step 17

9

  1. Turn ON the ignition with the engine OFF.
  2. Measure the voltage at the Camshaft Position sensor signal circuit to ground with the DMM.

Is the voltage less than the specified value?

1V

Go to Step 10

Go to Step 14

10

Probe the CMP signal circuit with the test lamp connected to battery voltage.

Does the test lamp illuminate?

--

Go to Step 15

Go to Step 11

11

  1. Turn OFF the ignition.
  2. Disconnect the PCM connector C1 located on the same side as the manufacturer's logo. Refer to PCM Replacement/Programming .
  3. Test the continuity of the Camshaft Position sensor signal circuit with the DMM. Refer to Testing for Continuity in Wiring Systems.

Is the resistance less than the specified value?

2ohms

Go to Step 18

Go to Step 16

12

Repair the open or short to ground in the Camshaft Position sensor B+ reference circuit. Refer to Wiring Repairs in Wiring Systems.

Is the action complete?

--

Go to Step 20

--

13

Repair the open in the Camshaft Position sensor ground circuit. Refer to Wiring Repairs in Wiring Systems.

Is the action complete?

--

Go to Step 20

--

14

Repair the short to voltage in the Camshaft Position sensor signal circuit. Refer to Wiring Repairs in Wiring Systems.

Is the action complete?

--

Go to Step 20

--

15

Repair the short to ground in the Camshaft Position sensor signal circuit. Refer to Wiring Repairs in Wiring Systems.

Is the action complete?

--

Go to Step 20

--

16

Repair the open in the Camshaft Position sensor signal circuit. Refer to Wiring Repairs in Wiring Systems.

Is the action complete?

--

Go to Step 20

--

17

  1. Inspect for poor connections at the PCM. Refer to Testing for Intermittent and Poor Connections in Wiring Systems.
  2. If you find a poor connection, repair as necessary. Refer to Repairing Connector Terminals in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 20

Go to Step 19

18

Replace the Camshaft Position sensor. Refer to Camshaft Position (CMP) Sensor Replacement .

Is the action complete?

--

Go to Step 20

--

19

Important

Program the replacement PCM. Refer to PCM Replacement/Programming .

Replace the PCM.

Is the action complete?

--

Go to Step 20

--

20

  1. Select the Diagnostic Trouble Code (DTC) option and the Clear DTC Information option using the scan tool.
  2. Idle the engine at the normal operating temperature.
  3. Select the Diagnostic Trouble Code (DTC) option and the Specific DTC option, then enter the DTC number using the scan tool.
  4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text, if applicable.

Does the scan tool indicate that this test ran and passed?

--

Go to Step 21

Go to Step 2

21

Select the Capture Info option and the Review Info option using the scan tool.

Does the scan tool display any DTCs that you have not diagnosed?

--

Go to the applicable DTC Table

System OK

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