Circuit Description
The crankshaft position (CKP) sensor used on this engine is actually 2 sensors within a single housing. There are separate power, ground (reference low) and signal circuits connecting both sensors to the powertrain control module (PCM). The PCM supplies 12 volts to the CKP sensors.
The PCM can use three different modes of decoding crankshaft position. During normal operation, the PCM performs an Angle Based calculation using both signals to determine crankshaft position. The dual sensor allows the engine to run even if one signal is lost. If either signal is lost, the PCM switches to a Time Based method of calculating crankshaft position. If the system is operating in Time A mode, the PCM is using only the signal from sensor A. Time B indicates that the sensor B signal is being used. If the lost signal is restored, the PCM will continue to operate in Time A or B mode for the remainder of the current key cycle. The PCM will automatically revert back to the Angle mode on the next start up if the fault is not present. The scan tool can display the Crank Position Sensing Decode Mode.
Conditions for Running the DTC
The engine is cranking or running.
Conditions for Setting the DTC
The PCM detects a problem with the CKP sensor A signal.
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | Clear the MIL and the DTC with a scan tool. |
Diagnostic Aids
Notice: Use the connector test adapter kit J 35616-A for any test that
requires probing the following items:
• The PCM harness connectors • The electrical center fuse/relay cavities • The component terminals • The component harness connector
If the problem is intermittent, refer to Intermittent Conditions .
CKP/CMP sensor DTCs may set if the key is turned to Start and the starter is inoperative. If P0335, P0340, and P0385 are set and no trouble is found, check for the following:
| • | Is there a no-crank condition or an intermittent no-crank condition? |
| • | Was an attempt made to crank the engine with the shift lever not in P/N? |
Test Description
The number below refers to the step number on the diagnostic table.
Step
| Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | ||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |
2 | Does the engine start and run? | -- | Go to Step 3 | Go to Step 5 |
Does the scan tool indicate CKP Sensor Status Angle? | -- | Go to Step 4 | Go to Step 5 | |
4 | Move the related harnesses and connectors, by hand only, while monitoring the scan tool display. Does CKP Sensor Status change to Time A or Time B, or does an engine stall occur? | -- | Go to Step 12 | Go to Intermittent Conditions |
5 | The following steps apply to the sensor and the related circuitry that is malfunctioning. For example, if the scan tool indicates Time A, the system is using the signal from CKP sensor A. CKP sensor B and the related circuits should be diagnosed.
Does the DMM indicate the specified voltage? | B+ | Go to Step 6 | Go to Step 13 |
6 | Connect the DMM between the 12-volt reference circuit and the low reference circuit in the CKP sensor harness connector. Does the DMM indicate the specified voltage? | B+ | Go to Step 7 | Go to Step 14 |
7 | For the following test, the PCM must be commanded to look at the sensor being tested. Set the Crank Position Sensing Decode Mode to Time A when testing sensor A, and to Time B when testing sensor B.
Does the scan tool indicate RPM? | -- | Go to Step 19 | Go to Step 8 |
8 |
Does the scan tool indicate voltage? | -- | Go to Step 17 | Go to Step 9 |
9 | Using the DMM, inspect the signal circuit for continuity between the CKP sensor harness connector and the PCM harness connector. Does the DMM display the value shown or lower? | 5 ohms | Go to Step 10 | Go to Step 15 |
10 | Using the DMM, inspect for continuity between the signal circuit and ground. The DMM should display infinite resistance. Does the DMM display infinite resistance? | -- | Go to Step 11 | Go to Step 16 |
11 | Using the DMM, inspect for continuity between the CKP sensor A and the CKP sensor B signal circuits. The DMM should display infinite resistance. Does the DMM display infinite resistance? | -- | Go to Step 21 | Go to Step 18 |
12 | Repair the harness and the connections as necessary. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. Did you complete the repair? | -- | Go to Step 23 | -- |
13 | Repair the sensor 12-volt reference circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 23 | Go to Step 21 |
14 | Repair the open or high resistance in the low reference sensor circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 23 | Go to Step 21 |
15 | Repair the open or high resistance in the sensor signal in the circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 23 | Go to Step 21 |
16 | Repair the sensor signal circuit that is shorted to ground. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 23 | -- |
17 | Repair the sensor signal circuit that is shorted to power. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 23 | -- |
18 | Repair the signal circuits that are shorted together. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 23 | -- |
19 | Inspect for poor connections and for terminal tension at the CKP sensor. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 23 | Go to Step 20 |
20 |
Did you complete the replacement? | -- | Go to Step 23 | -- |
21 | Inspect for poor connections and for poor terminal tension at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 23 | Go to Step 22 |
22 |
Important: The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | -- | Go to Step 23 | -- |
23 |
Does the DTC run and pass? | -- | Go to Step 24 | Go to Step 2 |
24 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK | |
