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 MAF sensor is at least 5 g/s |
| • | The change in the calculated engine speed is at least 1000 RPM |
| • | The calculated engine speed equals 0 RPM and 4 or more CMP cycles have occured for a period of 2-3 seconds |
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, a rubbed through wire insulation, or a wire that is broken inside the insulation may cause an intermittent problem.
Thoroughly check any circuitry that is suspected of causing the intermittent condition. Check for the following conditions:
| • | Backed out terminals |
| • | Improper mating |
| • | Broken locks |
| • | Improperly formed or damaged terminals |
| • | Poor terminal to wiring connections |
| • | Physical damage to the wiring harness |
Inspect the face of the CKP sensor for metal shavings. This could result in an intermittent DTC P0339
Refer to Intermittents in Intermittent Conditions .
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
Checks the ignition feed circuit to the Crankshaft Position sensor
-
Checks the duty cycle of the Crankshaft Position sensor
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? | -- | ||
2 | Does the vehicle start and continue to run? | -- | Go to Diagnostic Aids | |
Is the test lamp ON? | -- | |||
4 | Connect the test lamp between the CKP sensor ignition feed and the CKP sensor Low circuit. Is the test lamp ON? | -- | ||
Is the duty cycle within the specified range? | 40%-60% | |||
6 | Repair the open or short to ground in the CKP sensor ignition feed circuit. Refer to Wiring Repairs in Engine Electrical. Is the action complete? | -- | -- | |
7 | Check the CKP sensor Low circuit for an open. Was a problem found? | -- | ||
8 |
Is the voltage above the specified value? | 10.0V | ||
9 | Check for an open in the CKP sensor (3X) signal circuit or an open in the CKP sensor Low circuit. Was a problem found? | -- | ||
10 |
Notice: In order to avoid damaging the replacement three-way catalytic converter, correct the engine misfire or mechanical fault before replacing the three-way catalytic converter. Replace the CKP sensor. Refer to Crankshaft Position (CKP) Sensor Replacement . Is the action complete? | -- | -- | |
11 | Repair as necessary. Is the action complete? | -- | -- | |
12 | Replace the VCM. Important: When replacing the VCM, the new VCM will need to be programmed. Refer to VCM Replacement/Programming . Is the action complete? | -- | -- | |
13 |
Does the scan tool indicate that this diagnostic ran and passed? | -- | ||
14 | 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 |
