• | 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 provides an overview of each diagnostic category. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
5-Volt Reference Circuit | P0641, P0651 | P0335 | P0651, P2135 | -- |
CKP Sensor Signal Circuit | P0335 | P0335 | P0335 | P0336 |
Low Reference Circuit | -- | P0335 | P0335 | -- |
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 between the peaks and valleys 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 sequence the ignition timing and fuel injection events for the engine. The ECM also uses CKP sensor output information to determine the crankshaft relative position to the camshaft, to detect cylinder misfire, and to control the CMP actuator, if equipped.
The CKP sensor signal circuit and the low reference circuits are also shared with the motor control module (MCM) 1. The MCM 1 uses the CKP signal to determine engine crankshaft position to enable the Auto-Start function.
• | 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 mass air flow (MAF) sensor, when airflow is greater than 3 grams per second, or by sensing camshaft position (CMP) sensor pulses.
The ECM detects that the engine is running, but has not received a CKP sensor pulse for 2 of 10 engine cycles.
• | DTC P0335 is a Type A DTC. |
• | The CMP actuator, if equipped, is commanded to the Park position. |
DTC P0335 is a Type A DTC.
The engine will crank over for 1-3 seconds, resulting in a no-start condition, if DTCs P0335, P0336, P1AC6 or P1AC7 are set.
Electronic Ignition (EI) System Description
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Control Module References for scan tool information
J 35616-A/BT-8637 Connector Test Adapter Kit
⇒ | If the hood position does not display Open, refer to Diagnostic Trouble Code (DTC) List - Vehicle for DTC P254F. |
• | Close routing of aftermarket electrical equipment |
• | Close to solenoids, motors, and relays |
⇒ | If any of these are determined to be a possible source of electrical interference, correct any wire harness routing or component placement conditions. |
⇒ | If the engine does not start, proceed with Circuit/System Testing. |
Important: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
⇒ | If the hood position does not display Open, refer to Diagnostic Trouble Code (DTC) List - Vehicle for DTC P254F. |
⇒ | If greater than the specified value, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM. |
⇒ | If less than the specified range, test the 5-volt reference circuit for an open/high resistance or short to ground. If the circuit tests normal, replace the ECM. |
⇒ | If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM. |
⇒ | If less than the specified range, test the signal circuit for an open/high resistance or short to ground. If the circuit tests normal, replace the ECM. |
⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM. |
⇒ | If the CKP active counter increments, test or replace the CKP sensor. |
⇒ | If the CKP active counter does not increment, replace the ECM. |
Important: You must perform the Circuit/System Testing before proceeding with Component Testing.
⇒ | If the hood position does not display Open, refer to Diagnostic Trouble Code (DTC) List - Vehicle for DTC P254F. |
⇒ | If the sensor is loose, incorrectly installed, or damaged, replace the CKP sensor. |
⇒ | If the parameter does not increment, replace the CKP sensor. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.