Do you still need help with this?Originally Posted by blackdog76
I can change VIN in ECM and TCM and hopefully write the correct file in for you,
You have an 8l90 correct? What year is your PCM from?
Do you still need help with this?
I can change VIN in ECM and TCM and hopefully write the correct file in for you,
You have an 8l90 correct? What year is your PCM from?
Ok so there is no more communication errors with the TCM but now it won?t move in any selected gear. My gear selector on my Dakota digital gauges is reading correct when I move the shifter and the gauges work off the OBDII port so I know the TCM knows what?s happening. I had my tuner flash the TUN info to the TCM so I?m not sure what?s happening now. What?s funny is the thing would go into gear with the Allison TCM.
Here is the latest tune file
Camaro0328 Retune (1).hpt
Last edited by blackdog76; 03-29-2022 at 05:46 PM.
The OS on the TCM probably isn't a match for the OS on the PCM. May need to sps flash that tcm to your vin then copy tune changes over.
They are the same. I bought a matched set from a 2015 Escalade with a 6.2 8L90. Then I sent both to my tuner and had him flash the TUN from the sticker on the side of my trans also.
Can someone look at the file and see if anything stands out?
My tuner told me to add transmission parameters but I’m not that versed with HPT yet.
Ok so I tried to do the fast learn and since I couldn't engine brake the car to heat it up (wouldn't go into drive) achieving 165 degrees took almost an hour! And the engine temps were around the 215 mark when I gave it gas to speed it up. And when I finally did get there I would follow the prompts to apply the brake. Didn't even get past that point because the fast adapt would abort after I had my foot on the brake for about a minute. I'm not sure if the TCM is seeing my brake signal. I'm tapped into the white wire on the switch and have the correct pin on the harness side so I'm not sure what the issue is.
So during all that, I'm not quite sure what I did, but I reset the adaptations several times, connected and disconnected HP tuners several times in the process and now it shifts and drives!!!
it moves now! Small victory since I've been at this since October. I'll try to test drive it in the next few days.
Last edited by blackdog76; 03-31-2022 at 12:57 PM.
Also have some codes still. The last one is a range sensor code and will set a P0700 as well when I try to shift. I’m guessing this is because I don’t have the shifter that the system is looking for?
0x7E8: P0073 - Ambient Air Temperature Sensor Circuit High (Permanent)
0x7E8: P0700 - Transmission Control System (MIL Request) (Pending, Current, Old, History)
0x7E8: U012A - Lost Communication with Chassis Control Module A (Permanent)
0x7E8: U18A2 - Lost Communication with Fuel Pump Driver Control Module (SES, Pending, Current, Permanent, History)
0x7EA: P18C2 (Permanent)
Last edited by blackdog76; 03-31-2022 at 01:38 PM.
Unfortunately not fixed. I added the PRNDL status channel and can see it shifting as I move the floor shifter. When I try to go into drive or beyond I get the message unknown 81 and unknown 82. With the associated permanent shifter code, something is definitely weird.
Ok so I might have an idea of what’s going on. The P18C2 is a trans gear position switch code. Apparently there are two different range switch harnesses for the 8L90. A 4 pin and a 10 pin.
Here’s a link to a bulletin.
https://static.nhtsa.gov/odi/tsbs/20...76306-9999.pdf
I have a 10 pin harness and might have a program for a 4 pin in my TCM.
Did you ever resolve this?
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