Trans Fail Safe Prompt?
 

On the way home the message center said "Trans Fail Safe Prong" 2002 4.4i 83,000 miles... it rode fine and shifted fine.

I did not have time to restart the car yet and see if it's still there but that don't sound good. Fail safe means to me the computer went it should limp home..but it shifted and ran fine. ?????

Is this common or common false?

Nice..I did a search and it can be anything from a Battery-Alternator-wheel speed sensor-neutral safety switch or just about any electrical part.

I reset the car by turning the key on and of 4 times...and no more display. I checked the batt 12.4 and charging at idle 14.3... I'll see what happens on the next drive..

I don't have a load tester but can get it done..this car has been sitting for 2 years prior to the last month of me driving it. The batt is fully charged and has been but the same AGM has been sitting dead for about a year...not good.

Well I had a the battery load tested this morning and it failed....New Decka gold maint free lead acid ,not AGM the battery specialist by me recommended.. 900 cranking amps.

Exact fit with batt overflow hose. 649MF $157.00 out the door installed.

Whats weird was I told him to put a batt in the cig lighter to keep all memory...he said not necessary and told me to start the car and he switched the battery with the engine running. Poss discontented first and positive installed first and it worked like a charm....no nasty lights. He said he does 100's of them like this without any issues. He said on the German cars you have to start them at least 3 months or the battery will start to go bad if your storing them..not on a maintainer. This one had a 2 year old Decka AGM in it before I bought it but it sat for one year dead. The charging system passed fine with my volt meter as well as the test to the battery with the engine off. It read 12.4. I did not have a load tester...the car with the old battery started every time and came to a full charge with the battery charger....I guess the German cars are very sensitive to voltage changes and the car knew the battery was starting to go. But to let you know the batt or alt is going bad with "trans fail safe prong" message is stupid"

Ok its back again....I've isolated it to when it happens only in park...either idling for 5-10 or just as you put it in park. If you drive away its in 3rd and that it..it does reverse. as soon as you shut it off and restart goes back to normal....it's not the trans. It sounds like the neutral safety switch or something to with park and electric switch. it' very intermittent but now it's happing more frequent.

It's going to a independent BMW guy Mon with full diagnosis tool. BMW wants $799 for a neutral safety switch..I found one at auto zone for $230 if that even possible...if it's that.

I bought this car from a friend and it was sitting for two years..I bought it as a winter car...my LS just spins in the snow. I would have bought a newer X5 but a good deal is a good deal. Now I'm getting pissed I've put like 4k in this thing making it perfect and now this thing pops up after two months... after much research search it can be anything!!! :(

If it's the neutral safety switch try starting it in Neutral, not Park. If it starts, then it's not the neutral safety switch.

Since it only occurs when you are idling for 5 or 10 minutes, it could be the thermostat in the trans cooler, or the thermal sensor in the trans. A scan should lead you to the problem and the solution.

Can someone find the BMW Repair TSB?
 

This is the exact problem....my car is a 2002 and I don't know the production date.

Thanks Upallnight for replying.

Original Recall from the NHTSA
Manufacturer's Report Date: August 14, 2001
NHTSA CAMPAIGN ID Number: 01V196000
NHTSA Action Number: N/A
Component: POWER TRAIN:AUTOMATIC TRANSMISSION:PARK/NEUTRAL START SWITCH
Potential Number of Units Affected: 14300
Summary: VEHICLE DESCRIPTION: 4.4I SPORT UTILITY VEHICLES. OVER AN EXTENDED PERIOD OF TIME, ABRASION PARTICLES COULD DEPOSIT ON THE ELECTRICAL CONTACTS WITHIN THE SWITCH, CAUSING A DISRUPTION OF THE ELECTRIC CURRENT THROUGH THE CONTACTS. IF THE DISRUPTION OCCURS WHEN THE VEHICLE IS STATIONARY WITH THE TRANSMISSION IN THE NEUTRAL OR PARK POSITIONS, THE TRANSMISSION WILL SWITCH AUTOMATICALLY INTO THE EMERGENCY PROGRAM, WHICH IS DISPLAYED IN THE INSTRUMENT CLUSTER VIA A WARNING LAMP AND A MESSAGE, "TRANS. FAIL-SAFE PROG." IN THIS CASE, THE VEHICLE CAN BE DRIVEN IN LOWER GEARS ONLY WITH LIMITED ENGINE OUTPUT.
Consequence: IF THIS PROBLEM OCCURS, THE ABILITY TO MAINTAIN SPEED IN TRAFFIC AND/OR ACCELERATE COULD BE GREATLY DIMINISHED, POSSIBLY LEADING TO A CRASH.
Remedy: DEALERS WILL REPLACE THE TRANSMISSION GEAR POSITION INDICATOR SWITCH. OWNER NOTIFICATION BEGAN AUGUST 14, 2001. OWNERS WHO TAKE THEIR VEHICLES TO AN AUTHORIZED DEALER ON AN AGREED UPON SERVICE DATE AND DO NOT RECEIVE THE FREE REMEDY WITHIN A REASONABLE TIME SHOULD CONTACT BMW AT 1-800-831-1117.
Notes: ALSO CONTACT THE NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION'S AUTO SAFETY HOTLINE AT 1-888-DASH-2-DOT (1-888-327-4236).

I found out the Recall is for the Natural Safety Switch also called park/neutral start switch. BMW had a recall than a TSB for 4.4's made between 9-1-99 and 2-28-2001 Mine was made 7-02 but this is the problem. I called BMW and they will do nothing.

The Trans Failure Prong only comes on in park either when you just put it in park it chimes and you get the display or if you idle for 5 mins....it's not all the time and intermittent but seems like it happing more. The tech said if that does not fix it there are 3 solenoids in the trans that are most likely the problem. I would think if it's stuck in limp mode they would be the problem. we will see.

I went to the independent this morning and he checked and cleaned the connections anyway but they were clean, he also could not pull any codes...only when it malfunctioned he could. He ordered a new neutral switch and we are going to try that...I'm not sure yet but I think the switch is around $300.

Here is a picture I found from another post..on this model the neutral switch is the square box on the outside.

http://i136.photobucket.com/albums/q...psd407cb74.jpg

This is the part OEM $305 online. Plug and play.

BMW Neutral Safety Switch - Genuine BMW 24107512755
http://i136.photobucket.com/albums/q...ps879c11cd.jpg

Here is some good info if you want to clear codes and you don't have a BMW tool.

-Hold gas pedal down
-Turn on key to number 2
-Continue to hold the has pedal to the floor for 30 secs
-Release the gas pedal and press it again to the floor for 10 seconds- than release.
-With key still in 2 position start car (foot off the gas)

On newer models you just have to hold your foot to the floor with the keep in #2 for 30 sec and a noise will sound and your done.

I would think that TSB is for a trans with the neutral safety switch inside the trans, were abrasive particles from the ATF could get into the switch and cause problems. The switch that's in the picture is mounted on the outside of the trans.

I had to replace a neutral safety switch a couple of years ago on a ZF trans, but it wasn't on a BMW. That neutral safety switch looks very similar to the one on my Audi A6 with the ZF 4HP18 trans. After replacing the switch I opened up the old switch and found that a few of the plastic pieces inside the switch had hairline cracks, enough to prevent or cause intermittent contact for the switch, so the computer wasn't able to decipher which gear the trans was in so it put the trans in limp mode.

http://c1552172.r72.cf0.rackcdn.com/19133_x600.jpg

The trans computer put the trans in limp mode when there are parameters from sensors that are not being met and to save the trans and get you home it goes to limp mode.

What were the codes that were pulled when it went into limp mode?

Upallnight... I verified buy the dealer it's on the outside under that square cover. Your picture has a different switch pictured and plug connection.

There are two plug connections on the trans, one for that switch and another for the trans ecm. I unplugged cleaned the connections for the hell of it. The plug connections were free of dirt but you never know if some white corrosion may be on a pin. I sprayed all connections down with ACF-50, I also sprayed the neutral safety switch. ACF-50 is like 100 times better than WD-40...Nothing against WD I still use it on other applications...I sprayed ACF-50 on my Triumph Speed Triple instrument cluster dash reset buttons that stopped working...it fixed them. So I drove the truck for 2 days now and no more warning messages. I'm replacing the switch anyway.

The tech did try and pull codes and nothing....I would have to get it in limp mode in order to pin point the defect. Because its intermittent it resets when you turn the key on and off. It can't pick up a bad circuit board unless it's inop at the time of testing.

I've researched this and found other owners have reported they replaced there neural safety switches to cure this problem. I've also seen complaints in deep snow or water people were getting the same complaints and it would go away...thees plugs must have been getting wet. BMW does a great job engineering but sometimes you have to scratch your head....such sensitive parts hung in the elements under the car 6 inches from the road exposed to all kinds of sh@t and that also has to stand up from heat off the trans. My guess is the part has deteriorated letting moisture in and corrosion.

I'm having it installed Mon will test all week and report if fixed. On my model this only effects 2000 to 2002 4.4's only so this is a small sampling of E53's..glad I found the recall/tsb and was able to diagnose this only happens in Park.

As I mention here : http://www.xoutpost.com/844101-post2.html the Range Rovers have an identical switch and connector but it has longer wires between the two so that the connector can be mounted above the bellhousing rather than below the pump housing

http://i260.photobucket.com/albums/i...ps021886ab.jpg

Phil

To verify that it is the switch when you replace it, take apart the old switch and see if there is corrosion in the switch. As I posted earlier, my didn't have corrosion, but hairline cracks, but taking the switch apart did prove to me that the switch was the cause of the Trans Failure issue. When my Audi went into Trans Failure mode I was able to read the code and it did state the switch was the cause of the code.

It's been about 6 days now and all I did way spray the ACF-50 on the trans connectors and neutral safety switch and no more trans failure prong. I drove it the same exact way when I got the light to come on and it's fixed.

I highly recommend anyone with an X5 unplug the two connectors to the trans and spray them down with Bowie Shield or ACF-50 and you will have trouble free operation especially if you live in the Northeast.

I'm having the neutral safety switch also changed just in case...the shop is backed up so maybe tomorrow.