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MCVGreg
MCVGreg, Master Troubleshooter
Category: Car
Satisfied Customers: 5984
Experience:  25 + Years Working with Cars & Electronic Control Systems
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1998 pontiac sunfire: the timing goes..crankshaft..camshaft position

Customer Question

On a 1998 pontiac sunfire I get P0335 and P0342 codes written to the computer only sometimes. When it happens the engine faulters like the timing goes way off. I changed the crankshaft and camshaft position senders. I even tried a different computer also ignition module. I checked all wiring and ground connections. I clear the codes and will come back after 3 to 10 starts This car has only 66k miles Help please. Lowell from Alton, IL
Submitted: 6 years ago.
Category: Car
Expert:  MCVGreg replied 6 years ago.

Hi Lowell & Welcome. Sorry to hear about the problems with your Sunfire.

I noticed that you did not mention that any "relearn" procedure was done when you replace the Crankshaft Position Sensor. According to both of the test charts for those error codes, it mentions that this procedure must be done any time the PCM is replaced or when the crankshaft position sensor is moved in any way. They are very sensitive. Even removing, inspecting, and putting the same part back into position can cause problems.

Here is the relearn procedure for the crankshaft position sensor. Unfortunately, it takes a GM Tech 2 scanner (or equivalent) to cause the procedure to occur.

CKP System Variation Learn Procedure

Important

A Crankshaft Position System Variation Learning Procedure must be performed any time a change is made to the crankshaft sensor to crankshaft relationship. Changing the crank sensor to crankshaft relationship will not allow the PCM to detect misfire at all speeds and loads accurately. Resulting in a possible false misfire DTC being set.

 

Removing a part for inspection and then reinstalling the same part is considered a disturbance. A false DTC P0300 could be set if this procedure is not performed.

The learn procedure is required after the following service procedures have been performed, regardless of whether or not DTC P1336 is set:

  • PCM replacement.
  • Engine replacement.
  • Crankshaft replacement.
  • Crankshaft position sensor replacement.
  • Any engine repair(s) which disturbs the crankshaft/harmonic balancer to the crankshaft position sensor relationship.

Caution

Before performing the Crankshaft Position System Variation Learning Procedure always set the vehicle parking brake and block the drive wheels in order to prevent personal injury. Release the throttle immediately when the engine starts to decelerate in order to eliminate over revving the engine. Once the learn procedure is completed, the control module will return engine control to the operator and the engine will respond to the throttle position.

 

Important

The battery must be fully charged and in good condition. The scan tool connection at the DLC is clean and tight before starting the Crankshaft Position System Variation Learning Procedure.

 

  1. Close the hood.
  2. Block the drive wheels and set the vehicle parking brake.
  3. Put the vehicle in Park or Neutral.
  4. Turn all the accessories OFF.
  5. Install a scan tool.
  6. Start and run the engine until it is at normal operating temperature 85°C (185°F).
  7. With the engine still running, enable the Crankshaft Position System Variation Learning Procedure with the scan tool.
  8. Press and hold the brake pedal firmly and raise the engine speed to the specified value, RELEASING the throttle as soon as the engine cuts out.
  9. Verify with the scan tool that the crankshaft variation has been learned.

Perform this procedure up to 10 times. If the PCM will not learn the variation, a DTC P1336 should be set.

Having this procedure performed may help resolve the problem. A reasonable shop should only charge you for the actual time it takes to perform the procedure.

I hope this helps.

Take Care, Greg A.

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