P0338

CIRCUIT DESCRIPTION
The Crankshaft Position (CKP) sensor sends a reference signal to the Vehicle Control Module (VCM) in order to indicate the crankshaft position and the RPM so that the VCM can determine when to pulse the ignition coil and the control ignition timing. This diagnostic will detect a low duty cycle from the crankshaft sensor. This is a type B DTC.

CONDITIONS FOR SETTING THE DTC
The following conditions will set the DTC:

^ The engine speed is less than 4000 RPM.
^ The MAF is at least 5 g/s.
^ The crank sensor duty cycle is greater than 50% (or the ratio High Ref to Low Ref is greater than 5.66).

ACTION TAKEN WHEN THE DTC SETS
The VCM stores the DTC to the history if the VCM detects an intermittent problem.

CONDITIONS FOR CLEARING THE MIL/DTC
A history DTC will clear if no fault conditions have been detected for 40° warm-up cycles (coolant temperature has risen 40°F from the start-up coolant temperature and the engine coolant temperature exceeds 160°F during that same ignition cycle) or the scan tool clearing feature has been used.

DIAGNOSTIC AIDS
A poor connection, rubbed through wire insulation, or a wire that is broken inside the insulation may cause an intermittent.

Thoroughly check any circuitry, that is suspected as causing the intermittent complaint, for the following conditions:

^ Backed out terminals
^ Improper mating
^ Broken locks
^ Improperly formed or damaged terminals
^ Poor terminal to wiring connections
OR
^ Physical damage to the wiring harness.

Refer to Intermittents.

Refer to Carbon Particle Removal from Evaporative Emissions (EVAP) System before starting repairs.

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

3. This step determines if DTC P0338 is the result of a hard failure or an intermittent condition.
5. Determines if voltage is available to the CKP through the VCM.
6. If the feed circuit is shorted to ground, the test lamp will be ON. This step determines if the circuit is open or shorted to ground. If the circuit is OK, then the VCM connections or VCM is faulty.
7. This test checks the crank sensor, crank sensor signal circuit and the VCM.