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#1
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Trans Prog Failsafe when cool outside. Battery? VR? Alternator? (N62)
2004 4.4 with 41k miles, garaged. On a Battery Tender Jr when it's in the garage since it's driven once or twice a week. Battery is now a little over two years old. Garage is not heated. Four or five times last winter, as soon as I shifted the X5 out of park or was about halfway down my block, and the temperature was in the forties or below, I got the TPF error along with the 4x4 warning light. I think the DSC light too, a couple of times. The temporary solution was to let the car warm up to about halfway to due north on the oil temperature gauge and then restart the car. The errors would then go away and everything worked normally. I'm in the Southwest, so it does not get below freezing often. No problems in the spring, summer or early fall. Three drain and replace ATF procedures, twice in late summer and yesterday. The mechatronic sleeve, magnets, gasket, plugs and filter were changed on the last one. Last two changes we added about 6.5 quarts of ATF at 86 F fluid temperature after going through the gears, monitored on a Foxwell 520 Pro. The transmission shifts smoothly. I got the TPF and 4x4 errors again two weeks ago when it was in the forties. Before starting the engine, the battery was at 12.2V. I used the Foxwell and set the Live Data to monitor the oil temp, gearbox oil temp, battery voltage and voltage at the transmission. Strangely, until the engine warmed up the voltage was 11.2 at both places. Once the engine was warm, both jumped to 14.1. I restarted the engine and everything was fine. No Service Engine Soon light. I saved the codes from the Foxwell last time, but couldn't find the file with them on the microSD card when I put it in my PC. There were codes for the transmission, alternator and several other modules. My guess is that they're related to the low voltage. Since the problem only happens when the temperature is colder, does it seem like a battery problem or is there something in the voltage regulator or alternator that would malfunction when it's colder outside? Last edited by haigha; 12-09-2019 at 01:05 PM. |
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#2
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Could well be a failing alternator (or rectifier/regulator on the back of the alternator. The symptoms fit.
You can monitor the voltage on the dash via hidden menu #7 (UBAT) while driving - if it gets below about 12.5-13v while moving, something is going to throw a fit - the trans in this case...
__________________
Wayne 2005 BMW X5 3.0d (b 02/05) 2001 BMW F650GS Dakar (b 06/01) |
#3
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Thanks, wpoll. Voltage was definitely low 11.2 when the problem last happened. The odd thing to me is that it has only happened when it has been colder outside (under 10 C). Also, though my X5 just turned 16, I've only put on 41k, which seems low for needing a new alternator (not an expert on that!).
I look at monitoring the voltage via the dash. A little easier than hooking up the Foxwell. |
#4
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I just got a new battery under warranty. Only $3 for the state fee. I'll update the thread if it turns out to be the VR / Alternator.
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#5
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map sensor
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#6
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Do you mean the MAF sensor? Would the TPF problem not appear all spring and summer? I wasn't aware that a MAF sensor issue only shows up when it's cooler outside (less than ~10 C).
So far, the problem hasn't reappeared since I replaced the battery on Wednesday. It hasn't been cold though. EDIT: I read some threads on MAF problems. I don't have a Service Engine Soon light and no rough idle. I just tested starting the car and voltage was 12.1 in position 0, and fluctuated between 13.8 and 14.1 after I started the engine. It's about 65 F / ~18 C outside. Last edited by haigha; 11-10-2019 at 03:23 PM. |
#7
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The MAP (Manifold Absolute Pressure) sensor is a totally different thing... and yes, our M57 diesel engines have both a MAF and a MAP.
__________________
Wayne 2005 BMW X5 3.0d (b 02/05) 2001 BMW F650GS Dakar (b 06/01) |
#8
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Quote:
Some colder nights this week, so I'll get to test to see if I get the TPF message with the new battery. |
#9
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Quote:
Some colder nights this week, so I'll get to test to see if I get the TPF message with the new battery. |
#10
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Quote:
I doubt this has anything to do with your MAF (Mass Air Flow) sensor. While it is known that MAF sensor issues can cause a change in trans shift behaviour (by design) I don't think it's common for this to be temperature related and certainly not to the point where a fail-safe condition is set. You also specifically mention seeing low voltages from time to time, something that IS known to cause a fail-safe condition. I work on the principal that if you smell smoke, look for a fire (there are no coincidences...).
__________________
Wayne 2005 BMW X5 3.0d (b 02/05) 2001 BMW F650GS Dakar (b 06/01) |
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