Problems with CKP relearn on 2001 12200411 PCM

[S10Wildside]

To perform the crank variation learn procedure with the Tech2, the brake pedal needs to be pressed. It may need to see the change as well, but I am not sure.

The service manual specifically mentions the PCM needing to see the change in the signal of the brake pedal. I was surprised to see that the my 2000 Firehawk (with 12200411 PCM) DID NOT need to see a change in the state of the brake switch.

The function of this switch could be added to EFI_Live to be enabled or disabled.

Could you further explain? Do you mean that I could somehow add this parameter to EFILive? This is how TunerCat OBDII displays the parameter. I would have expected to see this in the EFILive selection of parameters.




Latest Progress
Very little time to work with this engine. I did notice that the PCM recognizes second gear on the test stand. I'm going to have to play with the gear selector switch wires to figure out how to make the PCM see first gear. I think this may be the culprit. I may try again this week.

[S10Wildside]

I have to somehow figure out how to indicate 1st gear from the following information. Kinda stinks that the service manual does not provide more details for the PNP switch. I'll have to post the results after playing with various ground combinations on those four wires.

Taken from the service manual:

The PRNDL Circuit Board receives a combination of 2-4 grounded inputs from the Park/Neutral Position Switch indicating the gear position.

[ChipsByAl]

The PCM determines what gear you are in from the PSA or the pressure switch assembly. This is in the valve body and only active when the engine is running and the trans pump is working. When fluid is directed to the different pressure switches by the manual valve, the PCM can determine what gear the transmission is in.
The external switch is used for the neutral safety, reverse and PRNDL switches, not used on the F-body. The F-body has a switch at the shift control.
AL

[S10Wildside]

The PCM determines what gear you are in from the PSA or the pressure switch assembly. This is in the valve body and only active when the engine is running and the trans pump is working. When fluid is directed to the different pressure switches by the manual valve, the PCM can determine what gear the transmission is in.
The external switch is used for the neutral safety, reverse and PRNDL switches, not used on the F-body. The F-body has a switch at the shift control.
AL

Here's the f-body diagram.



If I have the correct diagram and if I understand this correctly, grounding circuit 1225 (DK BLU) wire will indicate 1st gear. Because that wire is currently open (to ground) on the test stand (the connector is not plugged into anything), the PCM sees this as open and is indicating 2nd gear. I'm not sure about the difference between 2nd and 3rd gear in this diagram though.

[joecar]

Do these help (from 4L60E Tech Guide)...

Note: the PSA tells the PCM the position of the gear selector lever, and not the current gear that the trans. is in;

the current gear is determined from the state of the 2 shift solenoids (PCM commands them and can read their the voltage state to see if they went to the correct state).

[joecar]

You want to signal PARK for CASE relearn, don't you...?

[S10Wildside]

Thanks for the images. I am able to signal park. I took another try again today, but the PCM didn't store the CKP relearn code. I flashed the PCM for use in my Firehawk, then reflashed it today for use with the test engine on the stand. Doesn't the full flash erase all CKP learn data? Any idea why the CKP relearn wasn't expected today?

There was so much less to mess with for OBDI.

[ChipsByAl]

Has the code P1345 ran and passed? If the correlation is incorrect between the cam sensor and the crank sensor the learn procedure won't run. The specification is + or - 2 degrees.
AL

[joecar]

Someone should check the Service Manual for the requirements needed for the crank relearn to proceed...

(I would check this, but my desktop's HDD crashed and I'm waiting for Dell support to get me a new one).

[S10Wildside]

Someone should check the Service Manual for the requirements needed for the crank relearn to proceed...

(I would check this, but my desktop's HDD crashed and I'm waiting for Dell support to get me a new one).

CKP System Variation Learn Procedure
1. Connect the scan tool.
2. Apply the vehicles parking brake.
3. Block the drive wheels.
4. Close the hood.
5. Place the vehicles transmission in Park (A/T) or Neutral (M/T).
6. Idle the engine until the coolant temperature reaches 65°C (150°F) .
7. Turn OFF all the accessories. IMPORTANT: If the CKP System Variation Learn Procedure cannot be completed successfully, refer to DTC P1336 for additional diagnostic information.
8. Enable the Crankshaft Position System Variation Learn Procedure with the scan tool. IMPORTANT: After the ignition switch is turned to the CRANK position, the Powertrain Control Module (PCM) must see a change in the state of brake switch (Released to Applied) to run the learn procedure. (My Firehawk did the procedure without this.) Also, the service brakes, not the parking brake, must be held throughout the duration of the learn procedure.
9. Apply and hold the service brakes. IMPORTANT: While the learn procedure is in progress, release the throttle immediately when the engine starts to decelerate. The engine control is returned to the operator and the engine will respond to throttle position after the learn procedure is complete.
10. Slowly raise the engine speed to 4,000 RPM .
11. Immediately release the throttle when the engine speed decreases.
12. Turn OFF the ignition for 15 seconds after the learn procedure is completed successfully.