For 1990-2009 cars

### Diagnostic Instructions

• | 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.

### DTC Descriptor

DTC P0341: Camshaft Position (CMP) Sensor Performance

### Diagnostic Fault Information

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 | --

### Circuit/System Description

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.

### Conditions for Running the DTC

• | DTC P0335, P0336, P0641, or P0651 is not set.

• | The engine is cranking or running.

• | DTC P0341 runs continuously when the above conditions are met.

### Conditions for Setting the DTC

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 was started, but has received less than 2 or more than 8 CMP sensor pulses during the first engine resolution.

• | 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.

### Action Taken When the DTC Sets

• | 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.

### Conditions for Clearing the DTC

DTC P0341 is a Type B DTC.

### Diagnostic Aids

• | 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.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Electronic Ignition (EI) System Description

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

#### Scan Tool Reference

Control Module References for scan tool information

#### Special Tools

J 35616-A/BT-8637 Connector Test Adapter Kit

### Circuit/System Verification

1. Ignition OFF, inspect the engine wiring harness carrying the CMP sensor circuits for the following conditions:

• | 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.

2. Start the engine. Using the live plot function on the scan tool, select the CMP sensor parameter. Change the minimum spec to 400, and the maximum spec to 4,000 RPM. Select the CKP sensor parameter. Change the minimum spec to 600, and the maximum spec to 3,300 RPM.
3. Observe the scan tool.
4. Quickly accelerate and release the accelerator pedal several times. Do not accelerate past 3,200 RPM. The graphed lines on the live plot display should track together across the screen.
5. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

### Circuit/System Testing

1. Ignition OFF, inspect the CMP sensor for looseness and correct installation.

⇒ | If the CMP sensor is loose, inspect the sensor and the O-ring for damage, and replace as necessary.

2. Inspect the engine for the following conditions:

• | Engine oil for debris

• | Camshaft reluctor wheel for damage

• | The timing chain, timing chain tensioner, and sprockets for wear or damage

⇒ | If debris is found in the engine oil, inspect the internal engine components to determine the cause. Repair or replace any worn or damaged components.

### Component Testing

Important: You must perform the Circuit/System Testing before proceeding with Component Testing.

1. Inspect the CMP sensor for correct installation. Remove the CMP sensor from the engine and inspect the sensor O-ring for damage.

⇒ | If the sensor is loose, incorrectly installed, or damaged, replace the CMP sensor.

2. Connect the CMP sensor harness connector to the CMP sensor.
3. Ignition ON, engine OFF, observe the CMP Active Counter parameter on the scan tool.
4. Pass a flat steel object across the tip of the sensor repeatedly. The CMP Active Counter parameter should increment with each pass of the steel object.

⇒ | If the parameter does not increment, replace the CMP sensor.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Camshaft Position Sensor Replacement

• | Engine Control Module Programming and Setup

• | Engine Control Module Replacement