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Old 03-16-2017, 03:26 PM
jb4realestate jb4realestate is offline
Join Date: Mar 2017
Location: Michigan
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Transmission Limp Mode after it warms up

2005 x5 4.4 with 98,000 miles. Currently: Limp Mode constant 100% of the time after truck warms up. Off and on does not reset. No slippage and is shifting fine. Just can drive more than 5 miles without Limp Mode popping.

Facts: New battery and alternator voltage is correct. Don't think this is voltage issues with battery or alternator. Scanning codes are always the same. Point of limp mode shows general voltage is within spec and temps all normal. Thinking it is cooling problem with bad temp sensor/wiring harness or TCM. Code is L1-L4. Any suggestions?

History: Been fighting the dreaded limp mode for a few months. Start happening randomly and not all the time. Code cleared by off and on. Limped around like this for a month as it was not every day. Could go a week without issues but it also might happen every 5 minutes. Speed and or distance driven did not matter.
Final got it into my into BMW certified Indi and we got after the repair. Only code was L1-L4, voltage drop. Started repair with fluid/filter change and rebuild of position switch as #1 issue to clear code. Oil was bad but not terrible thick. No metal flakes and Indi said internally everything looked good and truck shifted perfect without slippage when not in limp mode. While doing oil change they replaced seals and mechatronic adapter as precaution.

The position switch was gummed up but the wiring look solid. Cleaned up gunk and freshened up contacts. Thoroughly inspect all wiring up to TCM and all tested out good. After re-installation, the truck drove perfect with no issues for about 300 miles. After a normal drive to work, the truck was warm and I was pulling out of a parking lot. When switching from R to D, instant limp mode. Turned off and back on and code cleared. Took it back to Indi. The diagnoses was the same. Voltage drop L1-L4. Drove it that way for another week as we thought dielectric grease might have gotten on the contacts in the cleanup of the position switch and things just needed to settle in. Would be good for days and then other days would go into limp mode constantly. Off and on sometimes but not always would clear it. No speed or distance driven seemed to cause it. Would normally be on flat road and when there was lower torque on transmission. Did not matter which gear it was in. Truck could be cold or warm and that did not matter. Longer this condition lasted, off and on started to not clear limp mode. Instantly tripped when going form R-D or P-D after limp mode came on. Only way it would go away is if the truck sat long enough to cool down all the way. Took back to Indi and while on scanner back at the shop, scanner showed issues shifting through N-D. Scanner showed low voltage L1-L4 code. So, we picked up a tested and working used position switch to test. Made the swap and everything was perfect again. Drove truck for another couple hundred miles and then while driving around 30 MPH, limp mode came on. Off and on did not clear the code. Drove a mile home in limp mode and parked it. Parked the truck overnight with plans to take back to Indi in the morning. Started cold and everything was fine. Next morning, 1 block away from Indi and around 15 miles after driving, limp mode triggered. Scanned for codes and found same Code L1-L4. Indi suggest updating software before chasing parts as the last update was 2015. Indi is waiting on the latest update from his provider currently.

It's been a week now and I have been driving the truck 5 miles to work and back home every day. Last week I could make it back and forth without limp mode coming on. I could even drive 30 - 50 miles without issue as long as I did not change from D Ė P after warm up. Otherwise, after truck was warmed up, going form P-D would trigger limp mode every time and off and on would not clear it. When truck is cold, no issues.

Over the past few days, I started getting limp mode with every drive over 5 miles. Again, no reason for why. No heavy torque, random speeds and in all gears. Even happens just sitting at stop lights. I can't even go the 5 miles to work. As soon as the engine temp reaches about 75C on the dash OBC, it triggers limp mode. No way to clear it until the truck cools down. Start it cold and no code. Change gears and go from D-P back P-D without issues as long as the truck is cool. Thinking the position switch is not the real problem as the code L1-L4 suggests.

So, contrary to my Indiís thinking of this being software related, I suspect this is a temp issues. Maybe clogged lines or cooler after oil change. Recent code scan with Indi still shows no new codes and trans temp reported at 90C when code pops. Could the temp sensor be bad? I am thinking the oil is getting to hot and causing slight slipping which is throwing the L1-L4 code as ECU or TCM is not picking up the high temp and the only code it thinks might be the problem is L1-L4. Never had a speed sensor code pop up so I doubt that is the issue.

Any input would be great! Otherwise, we should have software update done tomorrow. If that does not fix it, I am going to suggest flushing line and cooler, maybe even new cooler and thermostat.
Next would be temp sensor maybe? Whatís your thoughts on bad TCM?
Also wondering about the wiring harness being bad even though Indi tested all wires and said it checked out. What else could cause limp mode after transmission warms up yet show no signs of slippage or shifting issues?

Thanks, in advance for any thoughts.
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