• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
• | Diagnostic Procedure Instructions provide an overview of each diagnostic category. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
5-Volt Reference Circuit | P0335, P0651, P2135 | P0335, P0336 | P0651 | -- |
CKP Sensor Signal Circuit | P0335 | P0335 | P0335 | P0336 |
Low Reference Circuit | P0335 | P0335 | -- | -- |
Circuit | Normal Range | Short to Ground | Open | Short to Voltage |
---|---|---|---|---|
Operating Conditions: Engine Running | ||||
5-Volt Reference Circuit | 1 | 2 | 2 | 2 |
CKP Sensor Signal Circuit | 1 | 2 | 2 | 2 |
Low Reference Circuit | 1 | 2 | 2 | -- |
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The crankshaft position (CKP) sensor circuits consist of an engine control module (ECM) supplied 5-volt reference circuit, low reference circuit and an output signal circuit. The CKP sensor is an internally magnetic biased digital output integrated circuit sensing device. The sensor detects magnetic flux changes of the teeth and slots of a 58-tooth reluctor wheel on the crankshaft. Each tooth on the reluctor wheel is spaced at 60-tooth spacing, with 2 missing teeth for the reference gap. The CKP sensor produces an ON/OFF DC voltage of varying frequency, with 58 output pulses per crankshaft revolution. The frequency of the CKP sensor output depends on the velocity of the crankshaft. The CKP sensor sends a digital signal, which represents an image of the crankshaft reluctor wheel, to the ECM as each tooth on the wheel rotates past the CKP sensor. The ECM uses each CKP signal pulse to determine crankshaft speed and decodes the crankshaft reluctor wheel reference gap to identify crankshaft position. This information is then used to determine the optimum ignition and injection points of the engine. The ECM also uses CKP sensor output information to determine the camshaft relative position to the crankshaft, to control camshaft phasing, and to detect cylinder misfire.
• | DTC P0340, P0341, P0641 or P0651 is not set. |
• | The engine is cranking or running. |
• | The DTC runs continuously when the above conditions are met. |
Important: The ECM detects engine movement by sensing the airflow through the MAF sensor is more than 3 g/s, or by sensing camshaft position (CMP) sensor pulses. |
• | The ECM detects that the starter is commanded on and the engine has been cranking for more than 4 seconds without a CKP sensor pulse. |
OR |
• | The ECM detects that the engine is running, but does not receive a CKP sensor pulse for 2 of 10 engine revolutions. |
OR |
• | The ECM detects that the engine is running, but does not sync. |
Important: The ECM detects engine movement by sensing the airflow through the MAF sensor is more than 3 g/s, or by sensing CMP sensor pulses. |
• | The ECM detects that the engine is running, but receives less than 55 or more than 61 CKP sensor pulses each engine revolution for 8 of 10 engine revolutions. |
OR |
• | The ECM detects that the engine is running, but more than 19 resyncs occur within 25 seconds. |
• | 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. |
• | 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. |
Inspect the CKP sensor connector and the ECM connector for corrosion.
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
⇒ | If the Engine Speed parameter displays a value other than the current engine speed, continue with Circuit/System Testing. |
⇒ | If the CKP Active Counter displays a value of 0, or a fixed value, continue with Circuit/System Testing. |
⇒ | If the CKP Resync Counter increments, continue with Circuit/System Testing. |
• | Close routing of secondary ignition wires |
• | Close routing of aftermarket electrical equipment |
• | Close to solenoids, motors, and relays |
⇒ | Correct any wire harness routing or component placement conditions, if it is determined to be a possible source of electrical interference. |
⇒ | If the voltage is less than 4.8 volts, test for an open in the 5-volt reference circuit between the ECM and the CKP sensor connector. If the circuit tests normal, replace the control module. |
⇒ | If the voltage is less than 4.8 volts, test for an open or a short to ground in the CKP sensor signal circuit between the ECM and the CKP sensor connector. If the circuit tests normal, replace the control module. |
⇒ | If the voltage is more than 5.2 volts, test for a short to voltage in the CKP sensor signal circuit between the ECM and the CKP sensor connector. If the circuit tests normal, replace the control module. |
⇒ | If the amperage is more than 3 mA, test the CKP sensor signal circuit for a short to the 5-volt reference circuit between the ECM and the CKP sensor connector. If the circuit tests normal, replace the control module. |
⇒ | If the CKP Active Counter parameter does not increment, replace the ECM. |
⇒ | If the voltage measured between the low reference circuit and the battery positive post is not the same as voltage measured between a good ground and the battery positive post, test for an open/high resistance in the low reference circuit between the ECM and the CKP sensor connector. If the circuit tests normal, replace the control module. |
⇒ | Repair or replace the CKP sensor, if necessary. |
⇒ | If the parameter remains at 0 or another fixed value, replace the CKP sensor. |
⇒ | If debris is found in the engine oil, inspect the engine components to determine the cause. |
⇒ | If the crankshaft reluctor wheel is damaged, replace the crankshaft. |
⇒ | If any parts are worn or damaged, replace as necessary. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for ECM replacement, setup, and programming |