98LSZ28

iTrader: (2)

ok so when i start the car with the scanner hooked up all is good, the pcs has good amperage at about 1.05-1.07 shifting into gear is fine, nice and smooth...then as you touch the throttle it drops as u rev higher then sets a po748 and drops to 0.0 amperage and goes back to harsh shifts from park to gear...any information would be helpful. thankyou.

p.s. have checked wires they have good resistance throughout. new pcs solenoid tested before installation.

performabuilt

iTrader: (25)

P0748 - Pressure Control Solenoid Circuit Electrical.
Its hard to say if you have checked everything but the code is electrical in nature and apparently either with the wiring /solenoid or PCM the circuit is either becoming open or shorted
Those type issues can be annoying to solve. If you have done any other work to the car I would also check over all ground connections.

FLT

iTrader: (1)

What year is this car?

98LSZ28

iTrader: (2)

It's a 1998 Z28

Greaseymec

iTrader: (9)

Isn't there a computer gound wire issue with a 98?

Mec

98LSZ28

iTrader: (2)

This may be a long shot in the dark, but I read somewhere that someone was experiencing the same problem and it was caused by the camshaft not producing enough vacuum. I have a T-REX cam with a 110lsa and it probably has not very much in the way of vacuum. Any imput on this?????

performabuilt

iTrader: (25)

No the code is and electrical code meaning the PCM is seeing either and open or a short in the PCS circuit. Its a hard electrical fault .Wiring/solenoid/grounds/power supply

98LSZ28

iTrader: (2)

Thanks, I have checked all the wiring except the grounds so far. with the scanner I have amperage at idle, then as i rev it the amperage drops which i assume is correct as the line pressure increases as the amperage decreases, then it sets the code and bang! 0 amps when i clear the code it works correctly again. i will check all grounds next. someone mentioned a ground wire prob with the 98's, have you heard of this before? where should i look for that?
Thanks!

Greaseymec

iTrader: (9)

I'll research it and get back to you. I thougt it was 98 but I will check on it.

Mec

ls1z28performer

hey man im haven the same problem my shifts are hard and i got the same dtc cde about the pressure control solenoid so im wondering if you fixed your problem maybe i have the same 1 or do u have any ideas?

98LSZ28

iTrader: (2)

ever find out anything on that ground issue with the 98's?? thanks

98LSZ28

iTrader: (2)

never figured mine out, did you have any luck with yours? I have since broke my transmission doing a launch at the track just to shake out any probs with car before i let my son drive it. I foud a big problem!LOL Think I may have broken the planetary gears as I now only have reverse gear. It was a sickening noise when it went!!! When I get the tranny out of the car I am going to check the backside of the engine for missing or lose ground wires as I can't see it now without pulling the intake off. Is there supposed to be a ground to the tranny itself?? This car was in pieces when I bought it so I am not 100% sure I have everything right!

98LSZ28

iTrader: (2)

Here are some pics of the broken part in my tranny. Anyone know what the heck it is called so I can research it?? Thanks!

performabuilt

iTrader: (25)

Thats the rear planet and of note it is not and OEM 5 pinion rear planet. I would replace it either with and OEM 5pin planet or and OEM 4 pinion planet

98LSZ28

iTrader: (2)

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this would cause the car to only have reverse gear? And do I understand you correctly, replace it with an OEM part? Would you use the 5 pin or 4 pin if it was yours? FWIW, i should be putting around 450hp to the rear wheels.

performabuilt

iTrader: (25)

Well either would do well at that power I am sure but I would go with OEM 5 pinion if available and OEM 4 if not .

98LSZ28

iTrader: (2)

Thank you! You guys on here are great!

98LSZ28

iTrader: (2)

Finally got the code to go away! Had to have my ECM reflashed back to the stock tune. Only code that came back was an EGR code because I have headers and don't have a EGR system anymore. Apparently someone had tuned the car before I got it and had butchered the DTC tables in the computer! All better now,well at least no codes! Now back to PBJ to put it on the treadmill(dyno) and get some numbers!