Replaced radiator. 2nd day, tranny jumped to "limp" mode. Code 17. Replaced coolant temp sensor and reset codes. Tranny still limping and now throwing a code 22. Any more ideas? Oh yeah, what is the other, smaller sensor next to the thermostat housing? Thanx
Welcome to Allpar. There are 2 coolant sensors, one single wire one for the dash gauge and one 2-wire one for the PCM. The 2-wire one is the one that will throw a PCM fault code.
The TCM stores transaxle fault codes and needs a special code reader to access those codes, if it comes to that. Engine coolant temp could possibly put the transaxle into limp-in as the 1989 valve body may not have had an internal ATF temp sensor yet.
Thanks. Here's a couple more symptom: Temperature is reaching 190 Degrees +-. Temp gauge is barely off the peg. After resetting the codes (by disconnecting battery) I'm still locked in 2nd gear but no fault code! I there a way to reset the transaxle fault codes?
A battery disconnect will also reset the TCM (transaxle control module) fault codes, but if it returns to 'limp-in' immediately afterwards, then you have an active or 'hard' fault code that isn't going away. If it is going into 'limp-in' (2nd gear), then the TCM has a fault code(s) stored in it.
There may be a problem with the single (violet) wire temp sensor if the temp gauge isn't being accurate.
How are you reading fault codes? The 'key dance' and counting the engine light blinks will only show you engine (PCM) faults and not transaxle (TCM) faults. You will need a special OBD 1 scan tool with the specific Chrysler connector cable to read TCM codes (like the DRB II or DRB III with Supercard or equivalent). The TCM communicates through the body diagnostic connector in the vicinity of the interior fuse box. http://jeep.zerok.ru/images/ATD-AW4/3.gif
Thermostat stuck open is usually the cause of a code 17, and that would keep it cold and in open-loop mode. Draining the system may have aggravated an aging thermostat. I'd replace it and make sure the air is bled out afterward.
Disconnecting the battery does that (at least with the original computer, replacement computers have permanent memory that is not reset).
Assuming the battery disconnect resets the computer but the transmission still remains in limp mode, the fault is a hard code as mentioned above. Some codes will immediately put the transmission into limp mode, others only after they occur a certain number of times during car operation. You really need the diagnostic codes from the transmission to diagnose it.
I have information that according to the service manual, there is NO TCM on this vehicle. The only readouts are from the ECM (or PCM). This controls the solenoid block on the transmission. I don't know who to believe! Very frustrating!
I found someone who has a Snap-on diagnostic tool that can read the tcm codes. I have a code 41. (That's the low/reverse solenoid circuit) Following the troubleshooting flowchart, I have conclude that I need to replace the controller. I can't find a part number on it. Can someone look that up for me or refer me to a site where I can? Thanks