DTC P1345 Crankshaft Position (CKP) - Camshaft Position (CMP) Correlation
DTC P1345 Crankshaft Position (CKP) - Camshaft Position (CMP) Correlation
DTC P1345 Crankshaft Position (CKP) - Camshaft Position (CMP) Correlation
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Chevy Pickup, GMC Pickup, Suburban, Tahoe, Yukon (VIN C/K) Service Manual
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 vehicle control module (VCM) will determine that an error has occurred.
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The control module illuminates the malfunction indicator lamp (MIL) the first time the diagnostic runs and fails. The control module will set the DTC and records the operating conditions at the time the diagnostic fails. The control module stores the failure information in the scan tools Freeze Frame/Failure Records.
Diagnostic Aids
Check the following items: A loose CMP sensor causing a variance in the sensor signal Excessive free play in the timing chain and gear assembly Incorrectly installed distributor - 1 tooth off in either advance or retard positions A loose distributor rotor on the distributor shaft A loose or missing distributor hold down bolt 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 check any circuitry that is suspected of causing the intermittent complaint. Refer to Intermittents and Poor Connections Diagnosis 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. 4. This test will determine if this DTC is intermittent. 5. When the engine speed is raised to 2000 RPM the camshaft retard offset should not vary more than 2 degrees. 6. If excessive pressure is used when performing this test unintentional damage to the
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distributor shaft could result. 7. 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. 8. If 0 degrees cannot be obtained during this procedure refer to Diagnostic Aids. Step Action Important: Before clearing the DTCs, use the scan tool Capture Info to save the Freeze Frame and Failure Records for reference. The control module's data is deleted once the Clear Info function is used. Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? 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)? Replace the Crankshaft Position Sensor. Refer to Crankshaft Position Sensor Replacement . Is the action complete? Perform the Camshaft Retard Offset test procedure as follows: 1. Install the scan tool. 2. Start the engine. 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? 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? Go to Step 5 Value(s) Yes No
-Go to Step 2
-Go to Step 3
Go to Step 4
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Go to Step 10
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1000 RPM -2 to 2
Go to Step 6
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With the engine at operating temperature and the engine OFF, perform the following procedure: 6 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? Check for proper installation of the distributor. Repair as necessary. Refer to Distributor Installation in Engine Mechanical. Did you find a problem? 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: 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 degrees camshaft retard? Replace the distributor. Refer to Distributor Replacement in Engine Electrical. Is the action complete? 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 which was set. 6. Operate the vehicle, with the Conditions for Setting this DTC, until the scan tool indicates the diagnostic Ran. Go to Step 10 Go to Diagnostic Aids --
Go to Step 9
Go to Step 7
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Go to Step 10
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10
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Does the scan tool indicate the diagnostic Passed? 11 Does the scan tool display any additional undiagnosed DTCs? --
Go to Step 2
System OK
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