Circuit Description
The crankshaft position sensor (CKP) is mounted in the right rear of the engine block above the starter. The CKP sensor works in conjunction with a 24X reluctor wheel mounted on the rear of the crankshaft. The CKP sensor has a powertrain control module (PCM) 12V power supply, a ground, and a signal circuit.
As the crankshaft rotates, the reluctor wheel teeth interrupt a magnetic field produced by a magnet within the sensor. The sensors internal circuitry detects this and produces a signal which the PCM reads. The PCM uses this signal to accurately measure crankshaft velocity which is a variable used in order to detect misfire. The PCM also uses the signal to control spark and fueling.
Conditions for Running the DTC
| • | No active mass air flow (MAF) DTCs |
| • | No active camshaft position (CMP) sensor DTCs |
| • | The CMP sensor is transitioning. |
| • | The MAF is more than 3 g/s. |
| • | The ignition switch in the crank mode |
Conditions for Setting the DTC
The PCM determines no signal from the CKP sensor for less than 3 seconds.
Action Taken When the DTC Sets
| • | The PCM illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
| • | The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the conditions to the Freeze Frame and updates the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The PCM turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A last test failed, or current DTC, clears when the diagnostic runs and does not fail. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | Use a scan tool in order to clear the MIL and the DTC. |
Diagnostic Aids
Important: Remove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM connector gaskets when diagnosing or replacing the PCM. Ensure that the gaskets are installed correctly. The gaskets prevent water intrusion into the PCM.
The following problems may cause this DTC to set:
| • | Poor connections and terminal tension at the sensor |
| • | Crankshaft reluctor wheel damage or improper installation |
| • | The sensor coming in contact with the reluctor wheel |
| • | The engine running out of fuel |
Using Freeze Frame and Failure Records data may aid in locating an intermittent condition. If you cannot duplicate the DTC, the information included in the Freeze Frame and Failure Records data can aid in determining how many miles since the DTC set. The Fail Counter and Pass Counter can also aid determining how many ignition cycles the diagnostic reported a pass or a fail. Operate the vehicle within the same Freeze Frame conditions such as RPM, load, vehicle speed, temperature, etc. that you observed. This will isolate when the DTC failed. For an intermittent condition, refer to Symptoms .
Excess crankshaft end play will cause the CKP sensor reluctor wheel to move out of alignment with the CKP sensor. This could result in any one of the following:
| • | A no start |
| • | A start and stall |
| • | Erratic performance |
For an intermittent, refer to Symptoms .
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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This step determines if the fault is present.
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This step simulates a CKP sensor signal to the PCM. If the PCM receives the signal, the fuel pump will operate for about two seconds. If the fuel pump operates, the condition is either terminal contact at the CKP sensor or the CKP sensor reluctor wheel.
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This test determines if the CKP sensor signal circuit or if the PCM is faulty.
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The CKP System Variation Learn Procedure must be performed anytime the relationship between the CKP sensor and the CKP reluctor wheel is changed.
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To inspect the reluctor wheel, remove the starter and rotate the crankshaft while viewing the reluctor wheel through the CKP sensor hole. If you cannot determine if the reluctor wheel is damaged, the oil pan may have to be removed.
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The CKP System Variation Learn Procedure must be performed anytime the relationship between the CKP sensor and the CKP reluctor wheel is changed.
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Before replacing the PCM, inspect the PCM harness connections.
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The repair is not complete if the scan tool indicates that the diagnostic ran and failed.
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||||||||
2 | Does the engine start and continue to run? | -- | ||||||||
Does the scan tool indicate that this diagnostic failed this ignition? | -- | Go to Diagnostic Aids | ||||||||
4 |
Caution: Before proceeding, remove the fuses for the ignition coil and fuel injector feed circuits in order to prevent personal injury from engine rotation, sparks, and excessive engine fueling.
Is the test lamp illuminated? | -- | ||||||||
5 | Connect the test lamp J 35616-200 between the CKP sensor ignition positive voltage circuit and the CKP sensor ground circuit. Is the test lamp illuminated? | -- | ||||||||
Momentarily connect the J 35616-200 test lamp between the CKP sensor signal circuit and the CKP sensor ignition positive voltage circuit. Does the fuel pump operate when ignition voltage was applied to the CKP sensor signal circuit? | -- | |||||||||
|
Important: Use the J 35616 connector test adapter kit when probing the PCM connectors. Refer to Using Connector Test Adapters in Wiring Systems.
Is the voltage within the specified range? | 4.0-6.0 V | |||||||||
8 | Test for an open or a short to ground in the CKP ignition positive voltage circuit. Did you find and repair the condition? | -- | ||||||||
9 | Test for an open or a poor connection in the CKP ground circuit. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. Did you find and repair the condition? | -- | ||||||||
10 | Test the CKP sensor signal circuit for the following:
Did you find and repair the condition? | -- | ||||||||
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Important: The CKP System Variation Learn Procedure must be performed anytime the relationship between the CKP sensor and the CKP reluctor wheel is changed. Refer to Crankshaft Position System Variation Learn . Remove the CKP sensor. Refer to Crankshaft Position Sensor Replacement . Visually inspect the CKP sensor for the following conditions:
Did you find and correct the condition? | -- | |||||||||
Visually inspect the CKP sensor reluctor wheel for damage. Did you find and correct the condition? | -- | |||||||||
13 |
Did you find and correct the condition? | -- | ||||||||
Is the action complete? | -- | -- | ||||||||
|
Important:: The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement . Is the action complete? | -- | -- | ||||||||
Does the scan tool indicate that this test passed? | -- | |||||||||
17 | Select the Capture Info option and the Review Info option using the scan tool. Are any DTCs displayed that you have not diagnosed? | -- | Go to the applicable DTC table | System OK |
