Have a 95 z28 with 4l60e a4... Never had any issue with transmission losing 1 and 4 gears till I was tuned.. I have tried replacing the 1-2 and 3-4 solenoids no change.. I can start off drive up through all 4 gears and stop 2times and on 3rd start when it shifts goes directly to 3rd gear (limp mode)... Tune was to set f/a ratios for my cold air intake.. Shaved heads.. Advanced timing for 93+ octane.. Removed a.i.r.. A/C... Any traction control deleted (to best of my knowledge it never had TCS)... And tcc lockup in 2nd and 3rd gears.. Anyone ever had similar issue? I have taken the car to Chevy dealership and no codes show up. I have a free retune with this guy but want to make sure the issue before I waste the retune.. Any help would be much appreciated

 

Did the Chevy dealer realize he needed an OBD-1 scanner with the correct adapter plug. There are a number of transmission codes that do not turn on the SES light.

 

I assume so.. They said they knew they had to have the adapter but I think I'm going to try another Chevy dealership and get a second opinion

 

Is there anyway to check the codes with a paperclip like the regular obd1 ports? If so what pins need to be jumped?

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'93 was the last year the pins could be shorted to read the codes. '94 and up require a real code reader or scan tool.

 

OK so I took it back to a different dealership and watched them read the codes nothing.. Even took one of the service guys for a ride to show exactly what it does.. Lost 1 and 4 and he connected the scanner again while car was running still no codes thrown

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Then we may want to move this to "drivetrain".

Let me know if you want it moved.

 

If the following post is not possible please move it for me.. Thank u

 

OK so tonight I unplugged the PCM and cleaned the maf sensor.. Put it all back together and everything worked fine until I was stopped and floored it to see what would happen... I must have started and stopped 20 times befote nailing the throttle.. The car didn't seem to want to shift outta 1st but finally did but very high rpm.. And then went back to 3rd immediately.. Thus I'm back into limp mode again.. Is it possible that the tune has too high rpms for 1st causing it to go into limp mode?

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So I have bought a new PCM and the stock programming doesn't cause limp mode.. What could have happened in the tune to cause this?

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