Transmission problem when check engine light is on

CMullin · **Joined:** Tue Oct 20, 2015 10:58 am **Posts:** 19

Hello,

I have a 2005 Jeep Liberty CRD.

Sometimes when I start my jeep in the morning and start driving, I hear a thump noise, and then the check engine light comes on. When the check engine light is on, the jeep runs horribly. It shifts early and very hard, it is terrible for the transmission and runs like it has a bad transmission. The RPMs also are very high when this happens. for example, it'll be at about 3 or 4 on the highway going 65mph instead of the usual 2rpms. I try not to drive it when this happens and bring it to a shop as soon as I can to have them reset the check engine light. When I reset the check engine light, the problem goes away completely and the jeep runs great.

This whole process happens every now and then but this issue has been going on for over a year. Sometimes it'll be 3 months before the light come back on and I have to go get it reset. But lately the light has been coming on more often, and I can't keep running to the shop to have them shut it off for me I really want to fix the underlying problem. I think I've noticed that the jeep gives me more trouble with this in the winter, especially when I try starting it after a cold night. That makes me this it could be a transmission temperature issue? I can't figure out what wrong, and when I brought it to the shop they said the transmission error codes that were showing up didn't even exist?

If anyone has experienced anything similar to this please let me know! I really want to keep my Jeep and want to fix it before the problem gets even worse.

Thank you!
Cristina

flash7210 · **Posted:** Thu May 12, 2016 8:54 pm

You need to start reading the codes instead of just clearing them.
No other way to know where the fault is.

papaindigo · **Posted:** Fri May 13, 2016 9:52 am

X2 on actually getting the stored codes rather than just clearing the CEL. Unfortunately if you are having tranny issues you will have to find a dealer or someone with a dealer equivalent code reader to pull tranny codes; readers such as at Autozone type places and the GDE tune/reader can only pull ECU codes.

That said you might try 1) having a basic tranny service done (replace both filters and use new ATF+4) it that has not been done relatively recently; 2) if not 1) try adding 1 qt ATF+4 as the tranny seems to "like" being really full; 3) consider whether or not you are having the occasional tranny fluid drain back problems that occur after vehicle sits for say 6-8+ hours. Symptoms of #3 include a) delayed engagement; b) engagement but after running say 100' horrible shifting/engine bucking/maybe a "hard" engine stall; c) sometimes a CEL that clears on its own after like 5 drive cycles. You can prevent this by cranking up; shift tranny to neutral (don't leave in Park as fluid circulates faster in neutral); hold a high idle (say 1200 rpm or so) while you fasten your seat belt and get radio set; drive off - if the problem goes away then do a tranny service as a common cause is a bad check valve in one of the filters.

CMullin · **Joined:** Tue Oct 20, 2015 10:58 am **Posts:** 19

Okay, so I brought it to a transmission shop to get diagnosed today. The codes now read that I have a bad transmission temperature sensor. They said it was reading 1000 degrees when the engine was cold and off. They are charging $300 to fix it. I tried looking online to see how much this part costs but couldn't find it. I found that the temperature sensor is actually built into the electronic innards of the transmission? Is $300 a good price for this job?

papaindigo · **Posted:** Fri May 13, 2016 4:55 pm

There is some discussion of this at viewtopic.php?f=5&t=69598 . If I'm reading things right the tranny sensor is part of the solenoid pack inside the transmission and if PN52119435AA is right the part runs ca. $150 list. Replacement requires dropping the tranny pan and, apparently, the valve body then putting thing back together. Pretty straight forward job might be 1.5hr labor plus cost of ATF+4 refill so $300 sounds reasonable. Be sure they use ATF+4 not some sort of "universal" tranny fluid (unless you really know the shop ask for the ATF+4 empties to prove that's what they used) and while in there spend a bit more an replace both filters to complete a routine tranny service.

CMullin · **Joined:** Tue Oct 20, 2015 10:58 am **Posts:** 19

Okay so I had all that done, but now another code is coming up. Before it was PO750, which was the temp sensor. I had that replaced along with the filters and ATF fluid replacement.

The check engine light came on again and now PO715 is coming up, which reads solenoid A. I have to bring it back to the shop Monday to see if they can diagnose what is wrong now. Now with the check engine light on the jeep runs with high RPMs but the hard shifting that happened before when the light was on went away.

senatorjohn · **Posted:** Mon Jun 06, 2016 6:53 am

Been having almost the same problem with my KJ CRD for over a year. During warmer weather the problem is less frequent. The MS solenoid and temperature sensor are the ones playing up. When I clear the codes, they often do not reoccur for up to a week. On a daily basis, once I clear the code or codes, they frequently do not reappear for the rest of the day. Have changed the spin on filter and refilled with ATF +4 about a year ago and the problem persists. Was thinking of swaping the TCM for my spare one. Also have a spare complete auto box that did not show any faults, so may swap solenoid packs also. Great car when not in fault mode. Autel US 703 reads and clears transmission codes but is superseded by a later model which I assume will do the same thing.
Regards,
John

Transmission problem when check engine light is on

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