Gearchangingproblems with STS

[monza]

Hello everyone, im new here and new on cars.

I have a 1993 Cadillac STS with the Northstarengine and i have a problem with it, it doesnt want to shift to the 3:rd or the 4:th gear, it just sticks with the 2:nd.

So I was wondering if anyone might know what the problem might be?

I have read the thread about a Cadillac that doesnt wanted to change to the 4:th, can it be a similar or even the same problem as my Cadillac have?

[KHE]

My off the cuff guess would be bad shift solenoids. Simultaneously press and hold the OFF and WARMER buttons on the climate control panel (or OFF and PASSENGER WARMER buttons if the car has dual zone climate control) and post any codes that are displayed on the information center.

[Jan Olsson]

My off the cuff guess would be bad shift solenoids. Simultaneously press and hold the OFF and WARMER buttons on the climate control panel (or OFF and PASSENGER WARMER buttons if the car has dual zone climate control) and post any codes that are displayed on the information center.

If you diagnose the codes to be the shift solenoids it is a usual fault on the -93 (and maybe -94? ) transmissions. It's an easy and inexpensive fix. Search for "shift solenoids"

[jlinde]

Probably as the other guys say it is IN the 4T80 but I got the 'service engine soon'

and after check it was code P076 and the shifts were very harsh and remained in 2nd

I did as the book said and cleared the code (via the panel). The automatic shifted OK

again but the fault came back after a couple of weeks.

In that case the error was because of a faulty PCM 'power control module' (driver circuit ).

The PCM for your car is around $180 remanufactured.

So do as said - check your codes and post them and you will get help.

If you are VERY lucky the fault CAN be intermittent.

/Jan L

[lothos]

Probably as the other guys say it is IN the 4T80 but I got the 'service engine soon'

and after check it was code P076 and the shifts were very harsh and remained in 2nd

A P076 should only cause hard shifting, it shouldn't keep you in 2nd gear I don't think.

[monza]

Hello again, im sorry i havent written anything in like 6 month, forgot all about it so the car has just been parked outside the house. I have to thank you all for the help so far.

Well the fault is still there and here is the codes i get from the PCM:

Code P029 History

Code P056 History

No IPC Code

No ACP Code

No SIR Code

Code T073 History

Code S044 History

And the Service Engine Soon-light is glowing.

I have looked up Code P029 and P056, my book says:

P029: Transaxle Shift ´B´Solenoid Problem

(1st, 3rd, 4th Gear)

P056: Transaxle Input Speed Sensor Circuit Problem

But the book doesnt contain the T073 and S044-codes.

So do you still think its going to work if i change the solenoid?

Im sorry if my english is strange on some parts, im from Sweden.

[lothos]

S044 Lift or Dive Signal Fault

T073 (PCM - EBTCM/EBCM Pulse Width Modulation Signal Fault)

Found this in a post by Jackc regarding the T073:

This code points to a communication loss between the PCM and the Brake/Traction contol module. According to my factory service manual, there are a couple of circuits that could be bad - or have bad connections - or there is a possibility of a problem with the PCM.