trans. failsafe prog and error codes

tonycajjo · #1 06-03-2010, 01:33 PM

It just started acting up. the trans doesn't seem to want to go in gears, it slips. i have the following codes:

P0721 Output Speed Sensor Range/Performance
P0733 Gear 3 Incorrect ratio

is the speed sensor this error code is talking about the one in the front wheel?

i was thinking it could be just a sensor somewhere, i have 94K on my 2002 4.4i. i was also thinking about bringing it in to get the trans flushed / and the valve body cleaned.

thoughts, suggestions?

i got the battery tested, and it tested fine. the charge was a bit low but this could be because i have not driven her much and was running an AC Inverter for sometime this week while camping.

Sponsored Links

TwinsPoppa · #2 06-03-2010, 01:53 PM

I'm thinking that if it actually allows you to shift into gears but are slipping that the tranny needs to be rebuilt. Bad clutch packs?

tonycajjo · #3 06-03-2010, 02:00 PM

yea, i was thinking it could be something with the torque converter, but i know these beasts can do strange things cause of a sensor in a wheel or loose wire here / there. the thing that leads me away from that is that it happened all of a sudden, wasn't like it did it once then didn't for a while or anything. just started yesterday.

TwinsPoppa · #4 06-03-2010, 02:17 PM

Quote:

Originally Posted by tonycajjo

yea, i was thinking it could be something with the torque converter, but i know these beasts can do strange things cause of a sensor in a wheel or loose wire here / there. the thing that leads me away from that is that it happened all of a sudden, wasn't like it did it once then didn't for a while or anything. just started yesterday.

Do you have problems using reverse? Seems like others have had problems with just losing reverse. I think I read that reverse and forward gears use separate clutch packs.

Not sure if its the clutch packs and that normally it would slowly start to slip or bang, it just quits. I guess it makes it more complicated if there are several issues with the tranny. Like maybe the valve body has issues too.

I say don't throw too much money at it and get it diagnosed properly at a shop or dealer. Can't hurt to ask here and search but I would feel better getting qualified mechanic to look at it. This trans failsafe prog is like a general idiot light like check engine and it could be any number of things - at least according to weasel.

I feel for ya and I'll cross my fingers hoping its just a sensor or something trivial.

rmani · #5 06-03-2010, 02:30 PM

have someone reset the trans program this can sometimes fix the problem

tonycajjo · #6 06-03-2010, 02:33 PM

thanks for the replies. i think im going to do a couple of things when i get outta work today.

check the trans fluid level and look for leaks. (top off if necessary through item #1 from the following link RealOEM.com BMW E53 X5 4.4i A5S440Z ATTACH.PARTS/ PACKINGS )

clean the front speed sensor connections. and any other electrical connection on the trans (maybe they need replacement, but i'm not even sure which one the error refers to.)

reset the codes and hope for the best.

tonycajjo · #7 06-03-2010, 02:34 PM

Quote:

Originally Posted by rmani

have someone reset the trans program this can sometimes fix the problem

using the 30 second method with the peddle down? i tried this when she was stuck at the bottom of my uphill drive way in 5th gear. i think it worked, i didn't hear any beep or any click but after i was back in first and able to get up the driveway. but the failsafe came back and slipping still occurred.

TwinsPoppa · #8 06-03-2010, 03:10 PM

Quote:

Originally Posted by tonycajjo

using the 30 second method with the peddle down? i tried this when she was stuck at the bottom of my uphill drive way in 5th gear. i think it worked, i didn't hear any beep or any click but after i was back in first and able to get up the driveway. but the failsafe came back and slipping still occurred.

Might be worth a shot to look into the input output sensors. I'm trying to locate them but not much luck. Thing is I don't know how failsafe mode actually feels, maybe you do. Because if its just in failsafe mode and its supposed to feel like its slipping, but its actually not and its normal, then it might just be a sensor/wiring problem.

I guess the output sensor is internal:

I have a 2003 X5 4.4i with 124K miles. Everythin... - JustAnswer

tonycajjo · #9 06-03-2010, 03:20 PM

yea, i think you're right. i'm hopeful that when i check the level it is low and i can add some fluid. now i wonder which fluid to buy... cause i can guarantee its low. else i can always drain a few quarts (Liters) and replace.

tonycajjo · #10 06-04-2010, 10:44 AM

update: so i drained some fluid, filled some fluid, ran her. then did that one more time. i also cleaned the connections to the sensors in the wheels and the connector for the trans itself. it seems to be better, no codes, no failsafe prog but it still seems to slip on second gear after accelerating from a stop. in manual mode it shifts on its own, like it doesn't know what speed its going hence the speed sensor error.

looks like i'm gonna need her in for service.

any trans experts have input on the speed sensor?

Sponsored Links