Note: You must perform the Circuit/System Testing before proceeding with Component Testing.
1. Inspect the crankshaft position sensor for correct installation. Remove the crankshaft position sensor from the engine and inspect the sensor
O-ring for damage.
锟斤拷If the sensor is loose, incorrectly installed, or damaged, replace the crankshaft position sensor.
2. Connect the crankshaft position sensor harness connector to the crankshaft position sensor.
3. Ignition ON, engine OFF. Observe the Crankshaft Position Active counter parameter on the scan tool.
4. Pass a flat steel object across the tip of the sensor repeatedly. The Crankshaft Position Active counter parameter should increment with each
pass of the steel object.
锟斤拷If the parameter does not increment, replace the crankshaft position sensor.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Crankshaft Position Sensor Replacement (See: Powertrain Management/Computers and Control Systems/Crankshaft Position
Sensor/Service and Repair)
* Engine Control Module Programming and Setup (See: Powertrain Management/Computers and Control Systems/Engine Control
Module/Testing and Inspection)
* Engine Control Module Replacement (See: Powertrain Management/Computers and Control Systems/Engine Control Module/Service and
Repair)
P0340
DTC P0340
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure
Instructions) provides an overview of each diagnostic category.
DTC Descriptor
DTC P0340
- Camshaft Position Sensor Circuit
Diagnostic Fault Information
Circuit/System Description
The 4X camshaft position sensor circuits consist of an engine control module (ECM) supplied 5 V reference circuit, low reference circuit, and an
output signal circuit. The camshaft position 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 camshaft position 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 2 narrow, and 2 wide output pulses per camshaft
revolution that represent an image of the camshaft reluctor wheel. The frequency of the camshaft position 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 camshaft position sensor output information to determine the camshaft
relative position to the crankshaft, to control the camshaft position actuator if equipped, and for limp-home operation.
Conditions for Running the DTC
* The mass air flow (MAF) is greater than 3 grams per second.
