OK here's one more transmission request. I have been reading the prior post and have come down to the following point.

Transmission goes into safe/limp/hard shift mode on a now-and-again pattern.
Sometimes it goes days/week between safe mode and other days it might do it four or five time in a row and then quit. Other times maybe once then shifts fine the rest of the day. Really no pattern at all.

State of the Bronco

Six month old new to me Bronco-only history was that it was yearly serviced by the dealer
144000 miles
No codes-I own a code reader
Speedometer/gages all work
O/D light is not flashing
Airbag light started flashing a code a week ago.


I did the following based on searches on this forum. Listed in the order which we performed them.

Cleaned the VSS on the differential

Replaced the VSS on the differential

Replaced the MLPS with new style connector

Drained trans/TC replaced fluid/filter and added drain plug

Drained and replaced differential fluid. (Very little sludge buildup in old fluid.)

Lightly checked for chaff/broken wires (any hot spots for rubbing?)


At this point a could use a little help in which direction to go. The issue (safe mode) come up at such erratic times I having trouble pinning it down. My first thought is it must a loose/rubbed wire or connection somewhere.

Any help would be great

Selkirk
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post in the transmission forum

 

What year Bronco is this and what engine does it have?

 

when you pulled codes did you do both KOEO KOER. I would test your TPS also as it must be functioning properly to give proper throttle info to ecu for tranny.

what fluid did you use in the tranny?

 

The fluid I used was eithier Valvoline max life or high mileage or something along those lines. It is a 1994 302 EB. It has 148k miles. I forgot to mention in the first post that I also cleaned the connector to the silenoid pack.(Very tough to get to). I did both of the test, KOEO and KOER. Did not get any codes from eithier.

Kemicalburns, what your calling the tps, is this the same as the mlps? I replaced the mlps with the correct ford one.

Selkirk

 

MLPS = Manual Lever Position Sensor - located on the tranny

TPS = Throttle position sensor - located on the engine - you may have to remove the throttle body to replace it (not sure on a 302).

 

OK-Will run the TPS test this weekend.

Selkirk

 

My 93 5.8 had the limp home triggered by a FPR (fuel pressure regulator). Didnt do it all the time, but got progressively worst.

Sometimes at cranking, it would crank and run, but roughly. The check engine light would come on and the tranny would go to 2nd (or whatever they go to) and was very sluggish. Then, after while, would straighten out and be O.K.

At first I thought the fuel pump was going out, but it obviously wasnt. After many trials, I discovered that if the vacuum line to the FPR was removed and plugged, it was O.K. That line is to provide high vacuum at idle or low speed which causes the FPR to reduce fuel pressure to the rails, since demand is not great. It wasnt the pump, because it supplies enough fuel for the hardest of kickdowns.

Have not checked fuel pressure and think I checked codes with a reader with no success. I have a brand new FPR on the shelf----since late last year Guess one day I may be walking , if I dont replace it.

I think anything that causes a check engine light and hard codes may cause the tranny problem.

Try the vacuum line to the FPR----if it dosnt work, at least it will give you something to do until you find the real problem

 

Just wanted to update everybody on what my status is. Being in college now I really haven't had much time to mess with the hard shifting errors and what not. But!, it's spring break now and I have time to look at it more deeply.

At this point I am really thinking that it is an electrical issue and not so much anything to do with the tranny. I have dropped the pan 3-4 times since owning the vehicle and their has never been any shavings or crap accumulated on the magnet or in/around the bottom of the pan. When she shifts good she shifts great, leading me to believe that the tranny is fine. (I think it might have actually been rebuilt at one point)

I am leaning towards a bad abs module, or a bad psom. I have been searching around steve83's site looking for diagrams and what not. I am also getting airbag code 51. Those codes tell me that their is a bad fuse in the airbag unit, and I found a video on youtube (thanks pfun41 ) on how to replace it.

At this point , when it stops raining, I am going to check the abs module out. I am also going to check out all associated wiring to make sure their aren't any broken/chaffed wires. If yall have any advice or common hotspots to check for let me know.

Thanks in advance,
Patrick

 

Update- Cleared all codes last night from the past six months or so. Had a bunch stored up from a few fuel related issues that I was having so I cleared them all to start back over at square one. Drove it this morning and got it to act up on me. Hard shifting (fault mode), and got code 452 with KOEO, and got code 538 with KOER.

I believe the 538 happened due to the scanner not liking how the truck responded to the increase in throttle that was applied during the test.

However, the 452 reads 452 Ford- (Cars ONLY): Vehicle Speed Sensor (VSS) signal fault. This leads to believe like before that there is some sort of signal issue. Rather it be in the vss/abs system is what I'm trying to track down.

Note- Just would like to add that when I did the ghetto abs test on a wet road today and slammed on the brakes, they did not pulsate like an abs system is supposed to. Just a thought.

 

Clean the connectors under the master cylinder against the firewall. Also the PCM (ECM) connector down low against the fender. Sounds like you have replaced everything except the PCM and the shift solenoid assy. This place will check your PCM and repair it if they can ECMTOGO.COM. Mine runs and shifts better than ever since they did mine. Requires at least partial removal of the fender liner for removal.

I lived with code 51 for a year until the air bag module fried. Popped it out with no tools and took it to J/Y to match and found one that works great. Be sure to disconnect battery for 30 minutes to let the air bag capacitor drain.

I would not suggest a J/Y PCM as the numbers must match exactly and if your find a match it may have capacitors as bad as yours.

Our electronics that have been so good are finally feeling the years and heat...at least here in Texas.

 

A bad/failing VSS will cause the tranny to go into limp mode. I'm Curious though....you mentioned you changed the VSS on the Diff....is the VSS not located on the Transfer Case on later models as well ???

 

its no longer called the vss in the later model. its the rear abs sensor located ontop of the rear diff. the VSS was only for models that had the sensor in the transfer case which was 89-91.

i would clear the codes again. then unplug your abs control module and place jumper wires in the connector so your speedo and such still work. I dont recall which at the moment (will have to search on FSB). anyhow that would take the 4wabs unit out of loop. if you still get the issue and code then you know the issue is probably in the wiring some place. Ive heard of a few guys finding a partialy exposed wire touching the frame causing a signal drop.

 

Did abs the blinking light test this morning,with the amber abs light in dash, and got a code 16- System Pass. Since it is intermittently acting up, may it not throw a code when the abs module is working effectively?

 

Code 11 or 111 is System pass, I don't know what code 16 is...