replaced my CKP Sensor (crankshaft position sensor)

[panzer dragoon]

I had codes:
p0335 = CKP Sensor A circuit performance
p1372 = CKP sensor A-B correlation

The starter comes out (2 long bolts) and that could take awhile because its a tight fit to unwire and get out. Disconnect wiring from starter also. The sensor is fairly easy to get out with 1 bolt holding it in. Make sure you disconnect the battery also. I put the front of my car on ramps. The sensor is almost a foot below the exhaust manifold in the middle of the engine block. I thought it would be directly under the exhaust manifold, but it's not.

Took about 2 hours, but I'm old and slow. If you have everything in position it may only take 1 hour or less.

The CKP sensor is about $105 from the dealer but GMpartsdirect.com has it for about $55. I didn't do the CKP System Variation Learn Procedure because I don't have a ($2500-3500) Tech2 GM scan tool. (The Equus and other scanners won't do this operation I think.) I tells you to do the CKP learn procedure, but my car runs just like before without doing it (other people have said this also). If my car was running funky I would have had to have it towed to a GM dealer for them to do it.

Everything runs good. No stalls under 1/4 temp and at low RPM (I kept it in 2nd gear with the revs over 1K-1.2K until it got over 1/4 temp mark. My sensor was bad for a year with it stalling at an intersection in Winter while warming up. You just put it in Neutral or park to restart it. Then 3 weeks later it did it again. Kind of scary at first. Then I read and webbed about it and figured it only stuttered at around 1/4 temp or less. That's when it switches to sensor A from B at this certain heat range. The sensor only got worse over time. The drop in revs is from 300-500rpm and enough to stall the engine when the sensor is bad.

[BNaylor]

Good post. Sounds a lot easier on the 3.5L versus the 3.8L.

Here's a good procedure for '98 Intrigues or any GM "W" body with the Series II 3800:

http://mykidz.net/GTP/CrankPosSensor.shtml

The CKPS case learn is recommended for optimum performance but not necessary. The problem is you're stuck with a GM dealer with a Tech II machine. The local dealer wanted $80 for what amounts to a one minute procedure.

[GMMerlin]

The CKP Variation Learn is done to prevent the PCM from counting false misfires.
Misfire detection is an important part of PCM operation and has to do with the changes in crankshaft speed as the engine reaches compression and combustion.
Not performing the CKP Variation learn could cause the PCM to set a false misfire DTC..

[GMMerlin]

Then I read and webbed about it and figured it only stuttered at around 1/4 temp or less. That's when it switches to sensor A from B at this certain heat range. The sensor only got worse over time. The drop in revs is from 300-500rpm and enough to stall the engine when the sensor is bad.

Not true, the PCM uses an Angle based timing strategy for determining crankshaft position, The A and B inputs are housed in 1 sensor and the angle that is created is how the timing strategy is determined.
If the sensor loses its A or B input, an intermittant loss of spark will occur, usually this will lead to a momentary misfire condition, but depending on engine conditions the engine could stall.
When the timing stategy is loss the PCM bases its timing on the crank sensor signal it saw..
The reason why your engine only acted up at a certain temp was because electronic componants are temp sensative and faults involving electronic componants can occur when the temp of a componant changes

What else do you want to know about the Premium V ignition system

[panzer dragoon]

GM-Merlin, I have aquestion for you. Why the 70 deg C or 158 deg F temp engine coolant temp in order to program the Crankshaft Position (System)Variation Learn Procedure?

I never had 1 stumble after it hit 1/4 temp or more. But it could be rough up to that point, but the worst stumbles (and stalls) were at that point. I lived with this condition for a year.

from AlldataDIY.com:
CKP System Variation Learn Procedure

The crankshaft position system variation compensating values are stored in the PCM non-volatile memory after a learn procedure has been performed. If the actual crankshaft position system variation is not within the crankshaft position system variation compensating values stored in the powertrain control module (PCM), DTC P0300 may set. Refer to Diagnostic Aids in DTC P0300 Engine Misfire Detected.

The Crankshaft Position System Variation Learn Procedure should be performed if any of the following conditions are true:

• DTC P1336 is not set.
• The PCM has been replaced.
• The PCM has been reprogrammed.
• The engine has been replaced.
• The crankshaft has been replaced.
• The crankshaft position (CKP) sensor has been replaced.

CAUTION: Set the vehicle parking brake and block the drive wheels when performing the Crankshaft Position System Variation Learning Procedure In order to prevent personal Injury. Release the throttle immediately when the engine starts to decelerate. Once the learn procedure is completed, the PCM will return the engine control to the operator and the engine will respond to the throttle position.


IMPORTANT:</B> The scan tool crankshaft position system variation learn function will be inhibited if the engine coolant temperature is less than 70°C (158°F). Allow the engine to warm to at least 70°C (158F) before attempting the Crankshaft Position System Variation Learn procedure.
The Crankshaft Position System Variation Learn function will be inhibited if any powertrain DTCs other than DTC P1336 are set before or during the Crankshaft Position System Variation Learn procedure. Diagnose and repair any DTCs, if set.

1. Set the parking brake.
2. Block the drive wheels.
3. Close the hood.
4. Start the engine and allow engine coolant temperature to reach at least 70°C (158°F).
5. Turn off the engine, then turn the key to On.
6. Select and enable the Crankshaft Position Variation Learn Procedure with the scan tool.
7. Start the engine.
8. Wait until instructed by the scan tool, then apply the brake pedal firmly.
9. Ensure that the transaxle is in Park.
10. Increase accelerator pedal position until the CKP System Variation Learn fuel cutoff is reached at 4050 RPM . Release the accelerator pedal after the second fuel cutoff is reached.
11. The crankshaft position system variation compensating values are learned when the RPM decreases back to idle. If the procedure terminates, refer to the Important above for instructions.
12. Observe the DTC status for DTC P1336.
13. If the scan tool indicates that DTC P1336 ran and passed, the Crankshaft Position System Variation Learn procedure is complete.
14. Use the scan tool to clear any DTCs. DTC P1336 will not automatically clear after a successful learn procedure. DTC P1336 will not clear from memory if the learn procedure was unsuccessful.

If the scan tool indicates that DTC P1336 failed or did not run, recheck for other DTCs that may have set during the procedure. If no DTCs other than P1336 are set, repeat the Crankshaft Position System Variation Learn procedure. If the learn procedure will not pass, a mechanical engine problem may exist.

[panzer dragoon]

General Description
The CKP sensor used on this engine is actually 2 sensors within a single housing. Each sensor has a separate power, ground, and signal circuit. The PCM supplies 12 volts to both sensors. The PCM provides the ground path, or sensor return circuit, from both sensors. The power and ground circuits are also connected to the Camshaft Position (CMP) Sensor. Two separate signal circuits connect the CKP sensor and the PCM.

The PCM can use 3 different modes of decoding the crankshaft position. During normal operation, the PCM performs an Angle Based calculation using both signals to determine the crankshaft position. The dual sensor allows the engine to run even if one signal is lost. If either signal is lost, the PCM switches to a Time Based method of calculating the crankshaft position. If the system is operating in Time A mode, the PCM is using only the signal from Sensor A. Time B indicates that the Sensor B signal is being used. It the lost signal is restored, the PCM will continue to operate in Time Based mode for the remainder of the current key cycle. The PCM will revert back to the Angle Based mode on the next start if the fault is no longer present. The scan tool can display the Crank Position Sensing Decode Mode. A problem with sensor A will set a DTC P0335. A problem with sensor B will set a P0385.

[BNaylor]

Originally Posted by GMMerlin

Not true, the PCM uses an Angle based timing strategy for determining crankshaft position, The A and B inputs are housed in 1 sensor and the angle that is created is how the timing strategy is determined.
If the sensor loses its A or B input, an intermittant loss of spark will occur, usually this will lead to a momentary misfire condition, but depending on engine conditions the engine could stall.
When the timing stategy is loss the PCM bases its timing on the crank sensor signal it saw..
The reason why your engine only acted up at a certain temp was because electronic componants are temp sensative and faults involving electronic componants can occur when the temp of a componant changes

What else do you want to know about the Premium V ignition system

I agree that misfire detection is important in that the primary purpose is to protect the CAT convertor.

All electronics components are heat sensitive and automotive is no exception. Until the engine warms up the PCM operates in open loop mode. It will switch to closed loop mode around 145 degrees referencing to the ECT temperature sensor and other pertinent sensor input parameters.

Also, when you replace a PCM module a case learn is recommended. I put in a re-programmed DHP PCM in my Grand Prix GTP over 2 years ago and did not have a case learn performed. It hasn't missed a beat nor have I encountered any misfire odb-ii DTC error codes.

BTW - The crank and camshaft position sensors are Hall-Effects sensors. The best way to check the outputs and timing is with an oscilloscope.

[GMMerlin]

GM-Merlin, I have aquestion for you. Why the 70 deg C or 158 deg F temp engine coolant temp in order to program the Crankshaft Position (System)Variation Learn Procedure?

For a number of reasons, first the engine has to be warmed up some so the clearances are reduced , next the engine needs to be in closed loop (this is when the PCM is using sensor input to control engine operation instead of a preprogrammed strategy).
Now these are just the parameters that need to be met to perform the procedure, not the parameters used for Angle based timing.
The Angle based timing strategy is used as soon as the CKP sensor sees the notch in the reluctor pass both the A and B sensor (less than a 30degree rotation of the crankshaft) if the PCM sees both sensor A and B inputs, the Angle based timing is used, if the PCM sees only 1 sensor input the SES light is turned on and the PCM bases timing on the sensor input it saw.
In a nutshell, Angle timing is more percise

[GMMerlin]

Originally Posted by bnaylor3400

I agree that misfire detection is important in that the primary purpose is to protect the CAT convertor.

All electronics components are heat sensitive and automotive is no exception. Until the engine warms up the PCM operates in open loop mode. It will switch to closed loop mode around 145 degrees referencing to the ECT temperature sensor and other pertinent sensor input parameters.

Also, when you replace a PCM module a case learn is recommended. I put in a re-programmed DHP PCM in my Grand Prix GTP over 2 years ago and did not have a case learn performed. It hasn't missed a beat nor have I encountered any misfire odb-ii DTC error codes.

BTW - The crank and camshaft position sensors are Hall-Effects sensors. The best way to check the outputs and timing is with an oscilloscope.

The reason for the CKP Variation Learn to to "customize" the PCM to the variations in crankshaft speeds as the engine is running..the crankshaft speeds up and slows down many times each revolution (has to do with if the piston is on a compression or combustion stroke).
This sets a threshold the PCM looks for to determine misfires.
If the CKP VL is not learned, the PCM COULD sense a false misfire and set a DTC..once the DTC is set and the code is current, the PCM freezes some of its control strategies such as ST fuel trim adjustments until the DTC passes.
True misfires will kill a converter, false misfires will not.
Performing the CKP VL prevents misdiagnosis of false misfires that could cause a DTC to be set.

Doesn't mean you have to perform the CKP VL, just means that you could misdiagnose a vehicle that hasn't had the procedure done.
The CKP VL is a procedure I perform on vehicles that have misfire codes set that I don't feel a misfire on..then I continue with verifying the concern.

[BNaylor]

Originally Posted by GMMerlin

The reason for the CKP Variation Learn to to "customize" the PCM to the variations in crankshaft speeds as the engine is running..the crankshaft speeds up and slows down many times each revolution (has to do with if the piston is on a compression or combustion stroke).
This sets a threshold the PCM looks for to determine misfires.
If the CKP VL is not learned, the PCM COULD sense a false misfire and set a DTC..once the DTC is set and the code is current, the PCM freezes some of its control strategies such as ST fuel trim adjustments until the DTC passes.
True misfires will kill a converter, false misfires will not.
Performing the CKP VL prevents misdiagnosis of false misfires that could cause a DTC to be set.

Doesn't mean you have to perform the CKP VL, just means that you could misdiagnose a vehicle that hasn't had the procedure done.
The CKP VL is a procedure I perform on vehicles that have misfire codes set that I don't feel a misfire on..then I continue with verifying the concern.

I don't disagree with you and understand your explanation. Basically, it is a calibration procedure, otherwise you could get an anomally (false misfire) which could throw you for a loop during the course of troubleshooting. The problem is a lot of DIY types don't have a Tech II machine. A lot of us have nice odb-ii scanners that can read GM manufacturer specific codes in addition to generic but that doesn't help. And a lot of us are probably too cheap to take it to a dealer.