P0753 1-2 Shift Code

[btay801]

After accelerating through a intersection and after reaching the side (in the 1-2 shift) my 2001 GTP bogged way down then came right back. Five seconds later "Service Engine Soon" light came on. It now feels like it is in 3rd all the time now.

Several threads sound like the same problem, but is there a way I can test at the "20 way/umbilical cord" connector for supply voltage and also check at the transaxle side to test the solenoid in question?

And if the 1-2 shift solenoid is the problem, how difficult is it to change? Do I have to pull the tranny?

I checked the TCC fuse under the hood with a test light as well as every other fuse in the engine compartment and cab.

Any suggestions for a code reader that will get me by that I don't have to take out a loan for?

[btay801]

I know there are a lot of really knowledgeable guys on here.

5 days and no one with any input? BNaylor? Tblake? RichTazz? GTPdad?

[tblake]

Sorry....

CHeck that connector for corrosion. Also check to make sure no trans fuses are blow. 3rd gear is "Limp In" default gear for your trans. Designed to default to 3rd in case it loses power or has a circuit issue.

To replace the solonoids, you wouldn't have to pull the transe. At the very least you would have to take the sidepan off, which in its self isn't a very easy task with the trans still in the car.

As for code readers. I have a acctron I got for christmas. It does a good job at reading basic, and I've even been able to pull GM extended codes. For the basic codes it usually lists the code defenition. For the extended ones it just lists "manufacurer extended service code" or something to that effect. Which leaves me to write down the P1xxx number and reasearch it in my chiltons or on the net. No biggy though. I think my model now sells for about 60.00 at most auto parts places.

[btay801]

Thanks for the response back tblake. I am going to clean the connector and reinstall. Are the trans fuses under the hood behind the battery? I checked all those with a test light. I heard that if there is a piece of debris that gets caught in the solenoid that it can cause this solenoid code. I am going to clear the codes and hope it was just a fluke code.

[BNaylor]

The same 12 volts from the engine compartment fuse box TCC fuse feeds all the solenoids, TFT, pressure switches, input sensors, etc so the issue sounds like just the 1-2 shift solenoid either electrical or mechanical.

You can ohm out the coil of the 1-2 shift solenoid through the connector transaxle side. PINs A and E look for around 19-24 ohms resistance. The PCM module supplies a ground to activate the solenoid which can be checked at PIN A (LT GREEN) wire.

If it is a valve body contamination issue try running some Seafoam tranny treatment through it.

[tblake]

Originally Posted by BNaylor

...If it is a valve body contamination issue try running some Seafoam tranny treatment through it.

What is the defenition of P0753? Does it point directly to a solonoids circuit? Because if it does, not much can be done besides properly diagnosis and repair. Like Bob suggested, it would be a good idea to owm check the solonoids through the trans connector.

[btay801]

UPDATE:
It turned out to be a damaged power wire downstream of the TCC fuse.
I wish I could say I found it and fixed it, but I just didn't have time and took it to a Transmission shop that a friend suggested. They ran a new wire, problem solved!

Thanks for all your help guys!

[tblake]

Cheaper than a trans rebuild!

[btay801]

I know! I thought it would be at least $800 for the solenoid replacement. They charged me 3 hours labor + diagnostic = $384. J & G trans of Utah. Good people to work with.