Circuit Description
The Crankshaft Position (CKP) sensor sends a reference signal to the Vehicle Control Module (VCM). The CKP reference signal is used to determine crankshaft position and engine RPM. This information is used by the VCM in order to determine when to pulse the ignition coil and to control the 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 engine speed is less than 4000 RPM |
| • | The MAF sensor is at least 5 g/s |
| • | The crank sensor duty cycle high reference to low reference ratio is less than 0.3125 |
Action Taken When the DTC Sets
The VCM will turn ON the MIL after 2 consecutive driving cycles with the fault active.
Conditions for Clearing the MIL/DTC
A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles (the 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.
Throroughly check any circuitry that is suspected of causing the intermittent complaint. Check 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 Intermittent Conditions .
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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This step determines if DTC P0337 is the result of a hard failure or an intermittent condition.
-
Determines if a voltage is available to the CKP through the VCM.
-
If the feed circuit is shorted to ground, the test lamp will light. This step determines if the circuit is open or shorted to ground. If the circuit is OK, then the VCM connections or VCM is malfunctioning.
-
This test checks the crank sensor, the crank sensor signal circuit and the VCM.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 |
Important: Before clearing the DTCs, use the scan tool to record the Freeze Frame and the Failure Records for reference. This data will be lost when the Clear Info function is used. Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | ||
Is the light ON? | -- | |||
Is the light ON? | -- | |||
Is the test light ON? | -- | |||
Is the duty cycle less than the specified value? | 40% | |||
6 | Check for a poor connection at the CKP sensor. Was a problem found? | -- | -- | |
7 | Check for an open in the CKP sensor low circuit. Was a problem found? | -- | ||
8 | Check for an open or a short to a ground in the CKP sensor feed circuit. Was a problem found? | -- | -- | |
9 | Check for a poor connection at the VCM. Was a problem found? | -- | ||
10 | Repair the short to ground in Crankshaft Position sensor 3X signal circuit. Refer to Wiring Repairs in Engine Electrical. Is the repair complete? | -- | -- | |
11 | Replace the malfunctioning CKP sensor. Refer to Crankshaft Position (CKP) Sensor Replacement . Is the action complete? | -- | -- | |
12 | Repair the circuit as necessary. Refer to Wiring Repairs in Engine Electrical. Is the action complete? | -- | -- | |
13 | Replace the VCM. Important: When replacing the VCM, the new VCM will need to be programmed. Refer to VCM Replacement/Programming . Is the replacement complete? | -- | -- | |
14 |
Does scan tool indicate that this diagnostic ran and passed? | -- | ||
15 | Use the scan tool in order to display the Capture Info and the Review Info. Are there any DTCs displayed that have not been diagnosed? | -- | Go to the applicable DTC table | System OK |
