GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2003 🢒 GMC MD Steel Tilt (W Model) 🢒 Engine 🢒 Engine Controls - 5.0L and 5.7L 🢒 DTC P1345

Circuit Description

This diagnostic trouble code (DTC) monitors the crankshaft position (CKP) and the camshaft position (CMP) signals to determine if they are synchronized. If both signals are not observed by the control module within a narrow time window, the powertrain control module (PCM) will determine that an error has occurred.

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC

When the engine is running, the cam sensor pulse is not detected at the correct relative position to the crankshaft position sensor pulse.

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 check following items:

    • A loose or missing distributor hold down bolt.
    • A loose CMP sensor causing a variance in the sensor signal.
    • An incorrectly installed distributor - 1 tooth off in either advance or retard positions.
    • A loose distributor rotor on the distributor shaft.
    • Excessive free play in the timing chain and gear assembly.

An intermittent may be caused by any of the following conditions:

    • A poor connection
    • Rubbed through wire insulation
    • A broken wire inside the insulation

Thoroughly inspect any circuitry that is suspected of causing the intermittent complaint. Refer to Testing for Intermittent and Poor Connections in Wiring Systems.

If a repair is necessary, refer to Wiring Repairs or Connector Repairs in Wiring Systems.

Test Description

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

  1. This test will determine if this DTC is intermittent.

    2.

  2. When the engine speed is raised to 2000 RPM the camshaft retard offset should not vary more than 2 degrees.

    3.

  3. If excessive pressure is used when performing this test unintentional damage to the distributor shaft could result.

    4.

  4. If the distributor is one tooth off in either the advanced or retard positions the vehicle may run but 0 degrees camshaft retard offset will not be obtained.

    5.

  5. If 0 degrees cannot be obtained during this procedure refer to Diagnostic Aids.

Step

Action

Values

Yes

No

Schematic Reference: Engine Controls Schematics

1

Did you perform the Diagnostic System Check-Engine Controls?

--

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2
  1. Install the scan tool.
  2. Start the engine.
  3. Use the scan tool in order to monitor the engine speed.

Does the engine speed fluctuate (up to twice the desired RPM)?

--

Go to Step 3

Go to Step 4

3

Replace the Crankshaft Position Sensor. Refer to Crankshaft Position Sensor Replacement .

Is the action complete?

--

Go to Step 10

--

4

Perform the Camshaft Retard Offset test procedure as follows:

  1. Install the scan tool.
  2. Start the engine.

    3. Important: The camshaft retard reading will not be accurate below 1000 RPM.

  3. Raise the engine speed to the first specified value.
  4. Monitor the camshaft retard with the scan tool.

Is the camshaft retard reading within the second specified value?

1000 RPM

-2° to 2°

Go to Step 5

Go to Step 6

5

  1. Note the camshaft retard reading from the previous step.
  2. Raise the engine speed to the first specified value.

Does the camshaft retard reading change more than the second specified value?

2000 RPM

2°

Go to Step 6

Go to Diagnostic Aids

6

With the engine at operating temperature and the engine OFF, perform the following procedure:

  1. Remove the distributor cap.
  2. Grasp the distributor rotor and gently attempt to rotate the rotor.

Does the rotor turn on the distributor shaft?

--

Go to Step 9

Go to Step 7

7

Check for proper installation of the distributor. Repair as necessary. Refer to Distributor Replacement .

Did you find a problem?

--

Go to Step 10

Go to Step 8

8

Perform the Camshaft Retard Offset adjustment procedure as follows:

  1. With the engine OFF slightly loosen the distributor hold down bolt.
  2. Start the engine and raise the engine speed to 1000 RPM.
  3. Using the scan tool monitor the camshaft retard offset.
  4. Rotate the distributor as follows:
    5. • To compensate for a negative reading rotate the distributor in the counterclockwise direction.
    • To compensate for a positive reading rotate the distributor in the clockwise direction.
  5. Repeat step 4 until 0 degrees offset is obtained.
  6. When 0 degrees has been obtained turn OFF the ignition and tighten the distributor hold down bolt.

Did you obtain 0° camshaft retard?

--

Go to Step 10

Go to Diagnostic Aids

9

Replace the distributor. Refer to Distributor Replacement .

Is the action complete?

--

Go to Step 10

--

10
  1. Using the scan tool, clear the DTCs.
  2. Start the engine.
  3. Allow the engine to idle until the engine reaches normal operating temperature.
  4. Select DTC and the Specific DTC function.
  5. Enter the DTC number that was set.
  6. Operate the vehicle, within the Conditions for Setting this DTC, until the scan tool indicates the diagnostic Ran.

Does the scan tool indicate the diagnostic Passed?

--

Go to Step 11

Go to Step 2

11

Does the scan tool display any additional undiagnosed DTCs?

--

Go to Diagnostic Trouble Code (DTC) List

System OK