Cold Weather Tranny Codes

[DirtyMatt]

I have been racking my brain on an issue I endure with my truck when it gets cold lately. When the temps get to 8°F or lower I get a CES light and the truck will go into limp mode without Reverse....no other message in the DIC. The truck is plugged in overnight and starts easily. The CES light doesn't come on right away, but after 2-3 minutes. I am also using the "high idle" as well once started. If I am not backed in the driveway, I clear the light and leave and the truck shifts and drives normally. Once the light is on, if I am to shut the truck off for 20 minutes or so and restart, the light remains on, but trucks runs normally. The light will go off within a day or so. Codes I am getting out are 0751,0756, 0757. The truck is a 2007.5 LMM Chevy CC/SB, with 59k on it. I am running a PPE programmer, Level 4, straight 5" MBRP exhaust, AFE Dry fliter. The tranny is a Suncoast, built by them with about 17K on it.

I have been researching this as much as I can and did run acrossed someone experiencing something similar to mine. He related it to a low voltage/weak battery issue when the high idle kicked up and the TCM didn't like it. The batteries are 3 years old. I ran the original AC Delco for 7 years. These are the Duralast Gold from Autozone.

 

[stroke250]

Check your fluid level.

 

[05_LLY]

All pressure codes, most likely low on fluid, the cold makes fluid shrink up a lil more than normal causing it to be low!

 

[JDT4430]

Me with an 09 and a friend with a 07 were having similar problems in what we call cold weather down hear in Texas (30-40) and I had read somewhere that over time the internal filter can crack on the neck so decided to change mine. Didn't see any cracks or anything but after changing mine I stopped having the issues and my buddy did the same with the same results. Now it had also been a while since I or him for that matter had changed the external filters so that may have been all it needed but I changed both at the same time and it has shifted great since. I wouldn't think yours would be and issue with filters at 17,000 miles but its a cheap place to start.

 

[DirtyMatt]

The fluid level looks good. That was the first thing I checked as well.

....I guess I should be more clear. I have checked the fluid several times, but with ambient temps in the -20 to 10°F, the warmest I can get the tranny is 120-130°F. At this temperature, the level shows up in the "cold check" area in the lower hash marks. This is slightly warmer than what is identified in the manual under the "cold check" procedure so maybe I am a little unclear how to interpret these results.

 

[stroke250]

Based on that, you are low on fluid. It needs to be warmer to get more accurate readings, but you are still low.

 

[Awenta]

Only reading that matters is hot


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[DirtyMatt]

Only reading that matters is hot

That is what I have always done, but have been limited with these friggin arctic temps :cold:

Based on that, you are low on fluid. It needs to be warmer to get more accurate readings, but you are still low.

I was going to add some, but was hesitant to "eyeball it" not knowing what it was when hot. Based on what I said above, any recommendations on how much to add? I was gonna start with half a quart but sure as hell don't want to go too much!

 

[IOWA LLY]

Adding to much will cause it overheat when your towing, in warm outside temps.

Since your only trying to diagnose a cold weather issue, your not going to hurt anything by adding a qt. Try it and see if it fixes your cold start codes.

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[DirtyMatt]

So I had a partial quart of fluid that I added to the tranny....about 0.75qt. Was still getting the light. For the last two days I sat in the truck as it warmed up to get an idea when the CES light was exactly coming on and discovered something interesting. Prior to this morning, I noticed the CES was coming on within a few minutes of being started. So today I stayed in the truck. The ambient temp was right at 0°F and the tranny was at 8°F and after the truck started I kept my foot on the brake so the high idle would not come on. I did so until the tranny reached a temp of about 30°F, took my foot off and the high idle came on and no CES light. Now I am really at a loss.

 

[stroke250]

Delaying the high idle kick in gave the system time to build some pressure/fluid to circulate. While I won't rule out a possible internal filter issue, I believe you are still low on fluid.

 

[fc8464]

Do you run a trans. pan heater?

 

[DirtyMatt]

Delaying the high idle kick in gave the system time to build some pressure/fluid to circulate. While I won't rule out a possible internal filter issue, I believe you are still low on fluid.

Do you think that with a problem with the internal filter I would see issues at different times other than when it is really cold?

We are finally come out of this cold spell this weekend and gonna be over 40° on Monday. I will get it up to proper temp then for sure.

 

[DirtyMatt]

Do you run a trans. pan heater?

I don't.

 

[DangerousDuramax]

You could put it in gear and lightly power brake to get the trans temp up quicker. Or put it in gear and set the emergency brake for about 10 mins. I agree with stroke250 and think your high idle is causing an issue while everything is below 0*. Its trying to flow a "thicker" fluid that doesn't want to move so to speak. Those of us in Texas don't have these kinds of problems so I'm just speculating.

 

[DirtyMatt]

It has been about 2 years on the new tranny and this is the coldest it's been in that time so to say this problem didn't exist from the beginning may not be telling the truth.