Really need some tranny help

[garrettbowman]

Ive got 117,000 kms on my 03 and only 4,000kms are mine. I had a problem start yesterday that to me seems like my tranny stays in high gear.

I left work and while taking off it felt like my e-brake was on and it took me a long time to get up to 80kph. Then when comming to a light again I dropped it down to 1st manually and shifted through with it being ok except shifts from 2 to 3 were very stiff. But I still cannot drive in "D" because it will not down shift to get power on its own.

Will a simple fluid (and I did make sure there was tranny fluid) and filter change do the trick or should i be thinking about major issues?

[PROSPHOTO]

I highly doubt that a trans fluid change will correct the problem :worried:

I'm looking into possibilities, but need some more info...sounds like limp mode when placed in D; Do you have a scanner? Is the check engine light on?

Scan the PCM for any transmission related codes...if there is, post the code #'s :yes:

[garrettbowman]

Actually just found my scanned this morning but haven't scanned it yet. But yes the check engine light is on. But I just installed a remote start and figured that tripped the light. Guess Im not that lucky.

but yes, "limp mode" would best describe it. I can floor the truck and it doesnt change accel. and rpms only increse by about 500.

But yesterday after this started I stopped the truck to pick something up, got back in and it worked 90% the rest of the drive home.

So far it seems that it will be ok, then it will shift really hard with a small clunk from 1st to second and then my problems start again.

[PROSPHOTO]

I've seen remote starts really screw with IPC's and transmission controls...if you hit a Class 2 communication line with one of the remote start wires, this will definitely occur :yes:

If you start the vehicle w/ the key, will it shift normal in D (does the condition occur mostly when you use the remote start)?

[Jozuah]

another member had this same problem IIRC right after installing a remote start, ill find the post and link to it

[garrettbowman]

WOW, I didn't know that was possible, But that would make sense because I remote started it then when I stopped to pick something up I just started it with the key and it seemed to work.

But I'm not sure I understand why or how to fix it. I'll wait for the other link.

[Jozuah]

having trouble locating the post. i haven't forgot about ya.. did you use hte GM-9 harness?

[garrettbowman]

I got the g-9 harness but when i pulled the dash cover off I found an old starter installed in the truck, so the harness was already hacked so I just confirmed my wire locations and installed right into the harness with mostly the previous connections

[Jozuah]

ah well this is interesting then.

this is what i have to offer since i cannot find the post about the problem.

scan the truck for codes FIRST and foremost post codes if you get them.
do you have onstar?

1) disconnect the battery NEG cable and let it sit while you do the next things.

2) yes i know it sucks but.... unplug your remote start box from the system and your bypass "UNLESS ITS A DIAL IT IN" REMOTE BYPASS.

reconnect the batt NEG side and hope for the best. if it works then great if not then see below.

3) remove all the wires that you touched that are related to the remote start and tape everything well.

4) try it again , if not then post the results

[PROSPHOTO]

:yes: WOW, I didn't know that was possible, But that would make sense because I remote started it then when I stopped to pick something up I just started it with the key and it seemed to work.

But I'm not sure I understand why or how to fix it. I'll wait for the other link.

What happens is (usually) when the remote start is used (if one of the wires is connected to a data wire), the remote start either grounds or powers the data and the PCM sees a signal missing or voltage that shouldn't be. The PCM looks at this as a problem and reverts the transmission into the limp mode to overcome (what it sees) a problem :undecided

If you have a communication related code, I would uninstall the remote start and make sure all of the factory wires are correct

I'm a bit late, Thanks Jozuah...Like he said, scan for codes before disconnecting battery!

[garrettbowman]

ok, thanks a bunch guys, I guess its good news that my tranny isnt going but man I was happy with the DIY remote start/alarm, oh well, guess Ill have to pay the pros this time.

I'll do that tonight and post tomorrow on my results, but I'm sure thats the issue considering the problem started after my install. Wish I knew how to correct the problem though, I hate to uninstall 4 hours of work just to pay $150 to have it re installed, :duh:

[vball61]

If your truck is remotely starting, then the GM-SL bypass module appears to be doing its job by sending the correct fuel enable (vehicle theft deterrent) password over serial data.

Your truck may be entering 'Reduced Engine Power Mode' as a result of the PCM detecting a fault in the Throttle Actuator Control system when remotely started. Check to make sure that the following circuits are getting 12v from your Compustar module during a remote start:

ACC/RUN/START - white wire from the ignition switch
RUN/START - pink wire from the ignition switch

[MisterP]

Forgive jumping to the end of your thread -

What you have experienced is "limp home mode". When a serious transmission-related fault is logged the vehicle will only allow forward motion in 2nd and 3rd gears, plus deny converter lockup. It is BAD to drive your transmission this way as starting off in 2nd gear will seriously burn your clutches, as well as create a big increase in transmission fluid temperatures as you have no converter lockup. When this happens immediately get your vehicle off the road and disconnect the battery for about 5-mins, that will reset the PCM and turn off the SES light and return normal tranny operation, but get the code scanned and the problem looked at right away by a very qualified professional; if not taken care of the fault will happen again and again until something inside the tranny breaks for good.

Mr. P.

[PROSPHOTO]

What you have experienced is "limp home mode".

:iagree:

When this happens immediately get your vehicle off the road and disconnect the battery for about 5-mins, that will reset the PCM and turn off the SES light and return normal tranny operation, but get the code scanned and the problem looked at right away by a very qualified professional; if not taken care of the fault will happen again and again until something inside the tranny breaks for good.

:nono: A qualified Tech will advise you not to reset the PCM, there is important information that is recorded at the time of the failure that will assist the technician in diagnosing the failure, and if you reset the PCM, this info will be cleared.

[MisterP]

:iagree:



:nono: A qualified Tech will advise you not to reset the PCM, there is important information that is recorded at the time of the failure that will assist the technician in diagnosing the failure, and if you reset the PCM, this info will be cleared.

The code will still be there in the buffer even though you've reset the SES light. Or are you saying there is more information logged than just the OBDII scan codes themselves? But I totally agree, don't just clear it and then drive it, you'll burn sh_t up doing that.

Mr. P.

[garrettbowman]

ok, I agree with you as well, Im going to start it with the key and take it easy on the way home. If I cant fix it tonight I'll tear the starter out. It still seems very wierd to me that the truck/tranny does this??

[Jozuah]

:iagree:



:nono: A qualified Tech will advise you not to reset the PCM, there is important information that is recorded at the time of the failure that will assist the technician in diagnosing the failure, and if you reset the PCM, this info will be cleared.

Is there not "hard" codes and "soft" codes? hard codes (light flashing) stay in the PCM until erased by a scanner. soft codes (are eraseable by disconnecting the PCM and waiting the magic time.

i clearly remember reading codes that were "stored" while scanning a vehicle before.

any advisment would be great on this for me.:hijacked

[PROSPHOTO]

There is more information than just the codes...Freeze frame & failure records are a snapshot of all of the PCM parameters at the time that the failure was detected (ECT, IAT, run time, Fuel command, loop status, etc.) An example of how useful this can be in diagnosing the concern (this specific) would be seeing the run time at 0-2 seconds, open loop operation, ECT & IAT at/around ambient temp...this would indicate that the failure occured when the vehicle was started for the first time in the morning (other information would also be their)

There is no buffer; you either clear the codes or you don't (including history codes)

Clearing the codes by disconnecting the battery or by using the scanner will do the same thing.

When the SES light is flashing, this indicates that the failure can cause catalyst damage (severe misfire)...The SES light on indicates any emission failure that will notresult in catalyst damage.

Hope this clears up a few things :D

[TrailBlazzin]

i am experiening the same problem, has it been solved yet???