'02 Lesabre CEL on states crankshaft sensor

[grump]

Good morning,
I have an '02 Lesabre that has had 5 crksft. sensors replaced in 2 years. 3 Borg Warner and two duralast, duralast because it was the first and both have warranties. Everytime I replace I remove the battery cable and run the car for 100+ miles to reset relays (computer). The CEL will come back on but the car runs fine, no problems. Inspection time coming up and need to pass inspection to receive new registration. Will not pass with CEL on. Had garage and auto parts house OB2 it and it comes up the same "Crankshaft sensor". Once the sensor is replaced is there a special procedure one must do to reset the computer, ICM, ? Am I missing something. All information appreciated..............Grump

 

[HotZ28]

If after the CKPS has been replaced and you have a current CEL, you need to have the Crankshaft Relearn Procedure performed. This would require a high level scanner, such as the Tech II at the dealer. If you have any performance shops, or tuners in you're area that are using HPtuners or EFI Live tuning software, they can do this also. You will just have to call a few shops and ask if they can do the crankshaft relearn. BTW, it would be a good idea to use an ACDelco CKPS if you have another failure.

CRANKSHAFT VARIATION RELEARN (CASE Learn)

”CASE” means: crankshaft angle sensor error.
A crankshaft variation relearn must be performed if:

A diagnostic trouble code of P1336 is present.
The computer has been replaced or re-programmed.
The crankshaft position sensor has been replaced.
The engine, harmonic balancer, clutch, or flywheel
have been: disassembled, removed, or replaced.
The crankshaft position variation learning feature
enables the computer to compensate for part
manufacturing tolerances. This allows the computer
to accurately detect an engine misfire throughout the
engine RPM range. The learning process is stored in the
computer’s memory and does not have to be repeated
unless one or more of the above conditions are present.


To perform the relearn, proceed as follows:

Connect a scan tool to make sure there are no trouble
codes stored in the computer’s memory. If there is any
power train trouble code other than P1336
(Crankshaft Position Variation not learned),
the computer will disable the relearn function until the
problem that caused the code has been eliminated. Also,
make sure that the engine coolant
and oil levels are at an acceptable level.
(check it when the engine is cold)

1. Set the parking brake and block the drive wheels.
Make sure that the hood is closed.
2. Start the engine and make sure that the engine coolant
temperature is at least 158 degrees F. (70 degrees C.)
3. Turn the engine off for at least 10 seconds.
4. Select the crankshaft position variation learn procedure
(CASE Learn)on your scan tool.
5. Make sure that the transmission is in Park,
Start the engine.
6. Apply the brakes and hold the pedal firmly.
7. Follow the scan tool instructions.

Remember: That you are going to increase the
engine speed to approximately 4000 RPM.
That’s the variation learn fuel cutoff RPM
(depending upon the engine), and that it’s important
to release the throttle when the engine RPM starts to
decrease as a result of the fuel cutoff going into effect.
Failure to do such will result in over revving of the engine,
causing possible engine damage.

8. Once the engine has returned to idle, check
the status of Diagnostic trouble code P1336.
If the scan tool indicates that the CASE has been
learned, the relearn procedure is now complete.
If CASE has not been learned, check for the
presence of other power train codes.
If any exist, correct the problem,
then repeat this procedure.

 

[grump]

Thanks for the info Z, not many places here sell ACDelco here. I buy online but need the part now. Thanks and will start searching for a shop with the scan tool. Seems to be an opinion on EFI and HPtuners on-line, should be okay one way or the other. Have a great weekend, we are drying out in the hill country of Cedar Park, Texas.

 

[gmfugitt]

Hotz28,
Do you know if the case relearn needs done if a code is not set. I replaced mine with one from autozone and did not get a code. I am wondering if maybe it is within tolerance to not set a code but not optimized for maximum efficiency or performance.

 

[HotZ28]

Normally, if you do not get a code (CEL) you are OK to go, without any side effects of efficiency or performance. Those that do set a code, should have a case relearn.

 

[grump1]

Good evening, just saw the follow up on the thread. Seems the cell has now changed to P0404 Egr low flow. Every thing looks clean, tube to intake, intake, throttle body, new and old egr valve will not satisfy cel. EGR purchase two months ago (amazon) Delphi unit, seems warped and make an exhaust leaking sound, old one does not leak, new gaskets. The car runs good but having issues now, 130,000 miles. My wives Lincoln has 201,000 with no issues. Feel like letting it go. Here is my new thread, help if you can. All info appreciate...........Grump


P0404 low flow egr
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Good Evening All,
'01 LeSabre with p0404 cel. Removed egr valve, remove tube from egr to intake, clean no obstructions. Intake clean no obstructions. Removed throttle body clean no obstructions. New egr makes a sound as if warped and leaking, replaced with old valve and took out for a 50 mile drive with no issues. CEL stayed off, this morning it came back on. Had cel read p1401 and P0404. Removed old valve and replace with new one. CEL came back on. Both valves are basically cleaned but old one may be bad. Had shop read cel and stated egr bad, bought new one amazon Delphi. Other than the valve, what else could cause the cel to come on. Need to send back egr and have replaced, it is about 2 months old. Can the tube going to the exhaust downside be causing the issue. All information appreciated............Grump

 

[HotZ28]

If the new EGR is actually warped, you can get false readings. Any leakage in the exhaust downside could cause the same issue. It takes time & miles for the monitor to set those codes. It could be as little as 25-miles, or as high as 100-miles. http://easyautodiagnostics.com/gm/4.3L-5.0L-5.7L/egr-valve-tests-1

 

[grump1]

Thanks Z, I saw that link and will try it out. I have all the tools accept the wire piercing tool, if I sharpen the leads that should work also until I locate the tool. I placed a straight edge under the Egr pad and saw daylight, hence the warp part. Will run the test procedures and determine if old Egr is truly bad and return the newer one back to amazon for a replacement as it seems to be warped. Other than that I do not see an issue with Egr tube, intake is maybe six months old and does not seem clogged. The tube that goes to the exhaust side down under could be in issue and have not read any thread on it clogging up. Once more into the breach and see what it brings me. Will keep you posted, thanks for intel.

 

[grump1]

Okay Z,
New EGR valve did not work, CEL came back on after 3 miles. Drove it 40 more for the hell of it and did not do any good. Read on Amazon comments from other buyers they received dead ones also. Could be bad, thinking about sending back and upgrading to an AC delco. I am thinking it may not be the EGR valve but something else. This weekend I will following the link you sent to see what is actually bad. The intake is like six months old, but I replaced only the upper side. Can the lower intake be clogged, it idles okay and runs great just CEL now says P0401. Running out of ideas, got anything?