Transaxle question

[acastleberry]

I've read a couple of posts about folks having some problems with the PCS and/or TCS in ther Malibus. I'm wondering if my problems are starting?

2001 Malibu LS, 3.1L V-6, 4-speed auto, 141K miles...

Shifts hard (lurches) when coming out of park. 1-2 shifts are very hard, 2-3 are sometimes hard, 3-4 is fine. Also, when I manually shift (stopped) from 4-3, I hear nothing. 3-2 and 2-1 i hear a hiss, sounds like it comes from the transaxle, that lasts about .5 seconds.

Any thoughts?

[maxwedge]

Get it scanned for trans codes by a trans tech, can see if the components you mention are acting up.

[Allbert]

Please come back and let us know how you make out.

[acastleberry]

Sure, I'll be back to let you guys know how it goes. It may be a while, though. Cash is kind of tight this time of the year.

[ram3736]

The plug that plugs into your air-flow meter in your intake has come loose. I unplug mine all the time to get harder shifts when I race.

[malibugtp]

are u talking about the IAT sensor, the maf sensor, or an other sensor

[wymi]

Originally Posted by malibugtp

are u talking about the IAT sensor, the maf sensor, or an other sensor

I had the exact same symptom on my 01 Malibu, it was the IAT sensor harness and plug assembly that went bad. It's about $20.00 at the dealer, easy to replace. You will probably get a code for the IAT sensor at some point, I did and changed the sensor, same problem, then I changed the IAT wire harness and plug assembly and all is well.

[acastleberry]

Originally Posted by wymi

I had the exact same symptom on my 01 Malibu, it was the IAT sensor harness and plug assembly that went bad. It's about $20.00 at the dealer, easy to replace. You will probably get a code for the IAT sensor at some point, I did and changed the sensor, same problem, then I changed the IAT wire harness and plug assembly and all is well.

Well, you may be on to something. I noticed the other day that my check engine bulb was blown, so I replaced it. It immediately lit and told me something was wrong (DUH!) so I plugged it up to my OBD scanner. P0113 was what I got, which is a high IAT sensor reading. Well, I replaced the IAT sensor, reset the code and the light was off for about 60 miles. On the way home from the store tonight, the light came back on. I got home and, you guessed it, P0113 again. I may try the harness next.

Could something as simple as the IAT code cause the hard shifts? I can see where the hard shifts during driving might occur, but I don't think that it would cause the hard shifts (lurches) when shifting into R or D when coming out of P or N. I think that I may still have issues, but I'll work them one at a time and see what happens.

[maxwedge]

Get it on a full scanner and see what the iat reads when cold, it may not agree with the coolant temps, that may set this code.

[wymi]

Yep, something as simple as a bad IAT harness can cause that banging in to gear and the hard shifts. I couldn't believe it either, but $20.00 later with the new harness and the problem is gone.

[acastleberry]

All right. I thought I'd come back and lay rest to this thread...

Two days ago, I went by my dealer and asked for the wiring harness for the IAT sensor. They said it was only a pigtail, so I went ahead and picked it up. I went home, spent about 20 minutes cutting the 750 feet of black tape they put on the wires, cut into the 2 IAT wires, spliced them, taped everything back up and plugged in the new plug to the IAT sensor. I reset the OBD code that was still showing, and 2 days and 250 miles later, it is still working perfectly. The hard shifts are gone and fuel milage looks like it is back to normal. It looks like my problems may be solved (for now .

A big thanks to everyone for their suggestions and a special thanks to wymi for nailing my problem!

[dgallo_2000]

IAT? What does that stand for? I am having some problems, and I want to look into that.

Thanks.

[acastleberry]

Originally Posted by dgallo_2000

IAT? What does that stand for? I am having some problems, and I want to look into that.

Thanks.

Intake Air Temperature

[tractorboy]

My transmision made a noise when I would back up, sort of a light circular scraping noise. I checked the trans fluid level and it was low. In my malibu there is not a trans dip stick , you have to check the level like a gearbox, unscrew the plug and transmission fluid should run out.