GM/Detroit 6.5L ENGINE CONTROLS – DTC P0035 Crankshaft Position (CKP) Sensor Circuit

Circuit Description
The crankshaft position sensor is a hall-effect type sensor that monitors crankshaft position and speed.
There are four teeth 90 degrees apart on the front of the crankshaft sprocket that induce a pulse in the sensor which is transmitted to the PCM. There is a physical one to one correspondence between the pump cam and crankshaft.

Conditions for Setting the DTC
• The PCM performs this DTC diagnostic continuously.
• The number of consecutive missing crank pulses are greater than or equal to 8.
• All diagnostic set conditions met for 2 seconds.

Action Taken When the DTC Sets
• The PCM illuminates the malfunction indicator lamp (MIL) on the first consecutive drive trip that the diagnostic runs and fails.
• The Freeze Frame records the operating conditions at the time of failure and updates the Failure Records.
• The PCM will activate Back Up fuel.

Conditions for Clearing the MIL/DTC
• The PCM will turn the MIL off after three consecutive trips without a fault condition.
• A History DTC will clear after forty consecutive warm up cycles that the diagnostic does not fail (coolant temperature has risen 5°C (40°F) from start up coolant temperature and engine coolant temperature exceeds 71 °C (160°F) that same ignition cycle.
• The use of a scan tool

Diagnostic Aids
When the PCM is in backup fuel, long crank times, fast idle and poor performance conditions will exist. Check for a good connection at crankshaft position sensor and at the PCM. Many intermittent problems are caused by poor electrical connections or wiring. When attempting to diagnose an intermittent problem, always begin by trying to reproduce the conditions under which the failure occurs. This usually involves raising the engine to a higher temperature or operating it near RPM that the problem occurs. Since heat and vibration are often the cause of an intermittent, this may bring out the failure.

Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.
2. This step will determine if DTC P0335 is the result of a hard failure or an intermittent condition.
4. This step checks the 5 volt reference circuit (the 5 volt reference may vary slightly).
5. This step checks the ground circuit.



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