Crank variation re-learn did not work

[Boost]

I replaced the CKP sensor in an '05 2500HD 6.0 gasser, LQ4 motor. I opened the scan tool, connected, validated modules, allowed the ECT to rise to the specified temperature range, and activated DVT (it turned green and said OK). But I clicked on the LEARN procedure and nothing happened. Also, when I activated DVT, the button for the crank / cam variation learn did not change (stayed empty without turning solid with color). What gives? Thanks

[Taz]

Hello Boost,

Not sure exactly what went wrong. From memory, for the CASE to be executed the ECT must be at least 150 F. You also must maintain constant brake switch input to the PCM - foot on the brake pedal the entire time of the test.

If memory serves, you may also configure the delay time in the Scan Tool - between clicking on the CASE button (in the Scan Tool) and depressing the accelerator pedal - to get the engine speed to 4000 - 5000 RPM range very briefly, before releasing the accelerator the moment the engine speed decreases.


Regards,
Taz

[Boost]

Thanks Taz. Hmmm, I'll double check if the foot on the brake activates it. Also, the TP had to be 0% but it was around 5% at idle??

[Taz]

I don’t believe the TP must be zero for the relearn to activate - although best to let the engine idle. If memory serves, the engine speed must be less than 2000 RPM or so, to initiate the relearn. Guessing the previous problem was either lack of brake input, or a related DTC, preventing the relearn.


Regards,
Taz

[joecar]

I replaced the CKP sensor in an '05 2500HD 6.0 gasser, LQ4 motor. I opened the scan tool, connected, validated modules, allowed the ECT to rise to the specified temperature range, and activated DVT (it turned green and said OK). But I clicked on the LEARN procedure and nothing happened. Also, when I activated DVT, the button for the crank / cam variation learn did not change (stayed empty without turning solid with color). What gives? Thanks

Did you then open the throttle to bring RPM above 4000 or 4500...?

[Boost]

No. And I just tried it again, and when you click on the button it momentarily gets dark just as the fuel trim one below it so I am not sure if it is actually on or not. What are the steps to perform the procedure? Will it give me any confirmation of progress instead of just blinking every time I click and then nothing? I feel like I am doing it wrong... thanks

[Taz]

Steps are listed on pages 152 & 153 of the Scan Tool manual.

The manual is usually found at C:\Program Files\EFILive\V7.5\Doc.


Regards,
Taz

[joecar]

See here:

First warm up engine to operating temp...

then with vehicle parked and engine running at idle:
- connect scantool (click green connect button),
- goto DVT tab,
- select controller,
- click Activate,
- goto Learning subtab,
- click CASE (see next line),
- open throttle to increase RPM above 4000 within 10 seconds (see next line),
- when you hear/feel stumble/misfire immediately release throttle,
- let engine spindown to idle,
- after reaching idle, turn off engine and wait 15 seconds,
- while waiting 15 seconds, you can click Deactivate.

You may possibly have to have brake applied during this.