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Eric, Automotive Repair Shop Manager
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2002 Cavalier Camshaft sensor placement

Resolved Question:

2002 Cavalier Camshaft sensor placement
Submitted: 5 years ago.
Category: Chevy
Expert:  Eric replied 5 years ago.

Hi,

 

The 2.2L engine doesnt have a camshaft position(cmp) sensor.

 

CIRCUIT DESCRIPTION
This ignition system does not use a conventional camshaft position (CMP) sensor that detects valve train position. The ignition control module (ICM) detects when #1 or #3 cylinder has fired on its compression stroke using sensing circuitry integrated within each coil. The sensing circuit detects the polarity and the strength of the secondary voltage output, the higher output is always at the event cylinder. The ICM sends a CMP signal to the powertrain control module (PCM) based on the voltage difference between the event and waste cylinder firing energy. This system is called compression sense ignition. By monitoring the CMP and crankshaft position (CKP) signals, the PCM can accurately time the operation of the fuel injectors. If the PCM receives an intermittent CMP signal from the ICM, the CMP Resync Counter on the scan tool will increment. When the PCM cannot use the information from the CMP signal, DTC P0340 will set.

CONDITIONS FOR RUNNING THE DTC
The engine is running.

CONDITIONS FOR SETTING THE DTC
The PCM does not detect any change in the CMP signal for 35 crankshaft revolutions (70 combustion events) when manifold absolute pressure (map) is at 55 kPa or greater.

ACTION TAKEN WHEN THE DTC SETS

  • 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.

CONDITIONS FOR CLEARING THE DTC

  • 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.

DIAGNOSTIC AIDS

  • The following conditions may cause this DTC to set:
  • Low resistance in both the #1 and #3 secondary ignition circuits
  • High resistance in both the #4 and #2 secondary ignition circuits
  • An intermittent Crank Signal
  • An Intermittent crank signal will result in an interrupted cam signal and may set this DTC.
  • To locate an intermittent problem, use the scan tool to monitor CMP Active Counter parameter while running the engine. The counter should continuously count up to 255, then reset to zero. The counter will stop counting if a fault occurs in the cam signal circuit.

If this DTC is determined to be intermittent, refer to Intermittent Conditions

 

 

 

Customer: replied 5 years ago.
The engine light came on then the Trac Off light came on, Took it to Autozone for Diagnostic, Came up with P0340, Definition>Cam Sensor Condition> Explanation> Camshaft Position sensor is Monitored for Errors. Probable Cause1. Cam sensor Defective 2. Check Connector and Wiring.3. Engine Mechanical condition-Timing Belt/Chain out of time. So I thought I would start with the Sensor? But you say there is not one?
Expert:  Eric replied 5 years ago.

Hi,

 

Correct, there is no cmp sensor. what I provided above is straight from gm service manual for your vehicle. As it states, the cmp signal is sent to the on-board computer from the ICM(ignition control module). The ICM receives this signal from sensing circuitry built into the #1 and #3 ignition coils.

 

What you have to understand is that the code readers and definitions that Autozone uses are generic, which mean that they are generally applicable for all makes and models. But, they are not manufacturer specific for your particular make, model, and engine size.

 

The code definition for DTC P0340 for your specific vehicle and engine size is the one I provided.

 

Possible causes include:

 

  • faulty ICM
  • faulty #1 or #3 ignition coil
  • faulty ignition switch
  • open/short in wiring between ignition switch and ICM
  • faulty crankshaft postion sensor
  • faulty #2 or #4 ignition coil

The most accurate way to diagnose this problem is with a diagnsotic scanner with testing and live data capability in order to know which of the above is failing. If you decide not to have this done to determine problem, then you are left with replacing each part one at a time until problem is fixed, which will likely cost you several times as much as paying 1 hr labor for the diagnostics to be done. Then you can decide whether this is something you can repair yourself or not.

Eric, Automotive Repair Shop Manager
Category: Chevy
Satisfied Customers: 24959
Experience: 20+ yrs. experience as repair shop manager and technician.
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