• | 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 | P0107, P0452, P0522, P0532, P0641 | P0340 | P0641 | -- |
CMP Sensor Signal Circuit | P0340 | P0340 | P0340 | P0341 |
Low Reference Circuit | -- | P0340 | P0340 | -- |
The 4X camshaft position (CMP) sensor circuits consist of an engine control module (ECM) supplied 5-volt reference circuit, low reference circuit, and an output signal circuit. The CMP 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 4-tooth reluctor wheel attached to the camshaft. As each reluctor wheel tooth rotates past the CMP sensor, the resulting change in the magnetic field is used by the sensor electronics to produce a digital output pulse. The sensor returns a digital ON/OFF DC voltage pulse of varying frequency, with two narrow, and two wide output pulses per camshaft revolution that represent an image of the camshaft reluctor wheel. The frequency of the CMP sensor output depends on the velocity of the camshaft. The ECM decodes the narrow and wide tooth pattern to identify camshaft position. This information is then used to sequence the ignition timing and fuel injection events for the engine. The ECM also uses CMP sensor output information to determine the camshaft relative position to the crankshaft, to control the CMP actuator if equipped, and for limp-home operation.
• | DTC P0340, P0341, P0641, or P0651 is not set. |
• | The engine is cranking or running. |
• | MAF is greater than 3 grams per second. |
• | The DTC runs continuously when the above conditions are met. |
Important: The ECM detects engine movement by sensing the airflow through the MAF sensor, when airflow is greater than 3 grams per second, or by sensing crankshaft position (CKP) sensor pulses.
The ECM detects that the engine has started and is running, but receives less than 398 or more than 402 CMP pulses per 100 engine cycles in 800 of 1000 engine cycles.
• | DTC P0341 is a Type B DTC. |
• | The CMP actuator if equipped is commanded to the parked position. |
• | The ignition system defaults to a failed CMP sensor limp home mode. |
DTC P0341 is a Type B DTC.
• | With this DTC set, the engine may crank for an extended period of time during start-up. |
• | This test procedure requires that the vehicle battery has passed a load test and is completely charged. Refer to Battery Inspection/Test. |
Electronic Ignition (EI) System Description
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Control Module References for scan tool information
J 35616 Connector Test Adapter Kit
• | 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 CMP sensor is loose, inspect the sensor and the O-ring for damage, and replace as necessary. |
• | Engine oil for debris |
• | Camshaft reluctor wheel for damage |
• | The timing chain, timing chain tensioner, and sprockets for wear or damage |
⇒ | Repair or replace any worn or damaged components. Refer to Camshaft Position Actuator Cleaning and Inspection and also Camshaft Position Actuator Solenoid Valve Inspection. |
Important: You must perform the Circuit/System Testing before proceeding with Component Testing.
⇒ | If the sensor is loose, incorrectly installed, or damaged, replace the CMP sensor. |
⇒ | If the parameter does not increment, replace the CMP sensor. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.