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AW4 acting weird this morning...

Boveevil

NAXJA Forum User
Location
Gulf Breeze, FL
First off i have a 97 4.0, aw4, 231, with about 203k on the clock...
I was driving to work like normal (no o/d lock up sometimes).... been trying to chase that down as it locks some days and doesn't others... any how I come to a light and when it goes green. The Jeep trys to take off in 4th. had to drive it manually the rest of the way to work just like having the tcu unplugged, I only had 1st in 1-2 ,3rd and 4th, Cruise still worked, and no lock up.... So Im at work thinking "great, have to find a tcu for a 97." Well I get in it after work and it drives home like it has been for the past few weeks shifts fine, up and down. Still no o/d lock up. I unfortunetly have not had a chance to see if there is a ground or fuse or something that might have come loose?
:dunno:
Thanks for any help
 
When my NSS went bad, I did not have OD lockup. Do your reverse lights work? Not sure if the tranny starting in 4th is a symptom though. You could have other things going on.
 
Reverse lights work. I had cleaned the nss a few months ago... might be worth trying again. it may have gotten dirty/muddy after the last trail outing.
 
Could be the brake switch.. after time they stop working.
you could also run a TCC lock up switch.
 
When you cleaned the NSS, did you coat it the contacts with dielectric grease?
 
Just found out how to check the error codes....
pulled 12-66-45-55
12-batt disco w/i 50 key cycles
66-No message from the Transmission Control Module (TCM) to the Powertrain Control Module (PCM)
45-Trans temperature/ Governor pressure voltage out of range. Less than 1.55 or above 3.73volts for temperature and less than .1 or above 4.89 volts. Trans temp. to high or low. OD switch input too low for more than 5 mins
55-end


So Im guessing the tcu is bad and that would probably/hopefully explain the 45 code.
*sigh* anyone have a lead on a good 97 tcu ??
 
SOB, I'm having the same trouble and just posted not long after you. Let me know if it is the TCU, time to upgrade to a manual controler.
 
If you have OBD-II you should be using it. Two digit OBD-I style error codes are next to worthless compared to the P codes you can download from OBD-II.


Test the Throttle Position Sensor. The TPS and water do not like each other. The TPS data is used by the TCU and by the ECU to determine shift points.



You may have one or more of these Physical Symptoms:

1) The engine loses power and is stalling.
2) The engine will idle, but may die as soon as you press the gas pedal. When driving, it seems as if all power is gone.
3) Sometimes speed maxes out around 25 mph, and it feels as if the transmission is failed or isn't shifting properly, if at all. You can be going 25mph down the road at 5,000 RPM's. If you quickly jump on the gas you might be able to get the transmission to shift into second, but it won’t shift properly by itself. Shifting manually, the transmission goes through all the gears.

TEST

You should have 5 volts going into the TPS. At idle, TPS output voltage must be greater than 200 millivolts. At wide open throttle (WOT), TPS output voltage must be less than 4.8 volts.. The best is to use an analog meter (not digital) to see if the transition from idle to WOT is smooth with no dead spots. With your meter set for volts, put the black probe on a good ground like your negative battery terminal. With the key on, engine not running, test with the red probe of your meter (install a paper clip into the back of the plug of the TPS) to see which wire has the 5 volts. One of the other wires should show .26V (or so). The other wire will be the ground and should show no voltage. Move the throttle and look for smooth meter response up to the 4.49 at WOT.

Perform the test procedure again and wiggle and/or tap on the TPS while you watch the meter. If you notice any flat spots or abrupt changes in the meter readings, replace the TPS.
 
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