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  #1  
Old 09-23-2019, 08:29 PM
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Next diagnostic steps for E70 Power Tailgate not working?

Hi, everyone--


I've got a 2008 X5 E70 3.0si that has a power tailgate that suddenly stopped working.


I don't think it's the battery, because the power tailgate does not operate even when the vehicle is running. The alternator appears to be working, as the running voltage is just above 14V.


The mechanized latch operates (tailgate will lock and unlock). The red button to close the latch is lit, but pressing it just causes a motor to make a noise and then the tailgate makes a little movement but stops like it's stuck.


I have pulled the two fuses on the chart: Fuse 99 (40A) and fuse 121 (5A), and both test okay.


Now, I'm lost. What's the next thing to check or do?


I will keep reading other threads but haven't found anything that goes through all the steps yet.



I have no idea how to test the powered struts, but I figure that's what I'd test next.


Thanks in advance!
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Old 09-23-2019, 09:40 PM
ard ard is offline
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do you have a voltmeter and schematics?


www.newtis.info
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Old 09-23-2019, 09:43 PM
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Quote:
Originally Posted by ard View Post
do you have a voltmeter and schematics?

Definitely have a voltmeter. Didn't even know there are schematics available to the public.
Let me go look for them... Thanks!
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Old 09-23-2019, 10:16 PM
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Found it--thanks very much for the link!


Here is the link to the exact page for the wiring diagram.



https://www.newtis.info/tisv2/a/en/e...ration/lcnZ3ew
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Old 09-24-2019, 11:54 AM
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Just curious: is it true that the power tailgate system will throw codes that pinpoint the exact failure?


If so, does anyone know which code readers can pull these codes? Just checking before I waste money buying a code reader that won't do the job.


Thanks in advance!
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Old 09-24-2019, 08:28 PM
ard ard is offline
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Quote:
Originally Posted by dchang0 View Post
Just curious: is it true that the power tailgate system will throw codes that pinpoint the exact failure?


If so, does anyone know which code readers can pull these codes? Just checking before I waste money buying a code reader that won't do the job.


Thanks in advance!

Absolutely not.


Out of curiosity, someone selling service tell you that?
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Old 09-24-2019, 08:32 PM
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Quote:
Originally Posted by ard View Post
Absolutely not.


Out of curiosity, someone selling service tell you that?

No, I remember reading it in some discussion thread while trying to troubleshoot this. Can't remember how to find the discussion, though.


I remember the poster said that one of the two lift piston-like things threw a code that identified which one to replace.
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  #8  
Old 09-25-2019, 03:37 PM
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I took the power tailgate module out of the back and one of the connectors is corroded badly by water. I'll try to sand/file the connector contacts and get it shiny new again.
Might be the problem, or maybe there are multiple problems.


I may have to replace the cable harness (the one with the female plugs on it), since the pins are not exposed and thus can't be sanded.
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Old 09-25-2019, 04:42 PM
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Okay, I filed the pins a little bit and used acid flux paste and tinned the pins so that they are shiny. It is the input connector on the tailgate module (has RT/GE and RT/VI power in).


I stuck a wire into each of the pins on the female plug and scraped away.



I measured the voltage on both the white and black output plugs across MOT+ and MOT-. Both measure about 2.4VDC. I also measure 12VDC on both the white and black output plugs on the HALL_12V pin (GE on one, GE/SW on the other).


So the module looks okay. I can't prove that it's okay, but the output for both left and right sides match.


Then, I measured the spindles themselves. Measuring the resistance across MOT+ (GE/RT) and MOT- (GE/BR) came out to 2 ohms. Measuring the resistance across MOT+ (BL/RT) and MOT- (BL/BR) came out to 29.5 ohms.


So clearly, one motor is different than the other motor. Here are the two critical questions:


a) Which ohm reading indicates a broken motor, the 2 ohm or the 29.5 ohm?


b) Which color pair of wires is left, and which is right? In other words, is GE/RT & GE/BR the left side or the right side?


I figure I can answer b) by taking one of the spindles out and looking at the colors of the wires.


a) is the real critical question, because it can save me $250 to buy the correct side.


Thanks in advance!
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Old 09-25-2019, 04:51 PM
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Based on what I'm reading about 12VDC motors, the 2 ohm reading is much more likely to be correct for a good, working motor.


I suppose that if I take the spindle out and apply 12VDC to the motor, the good one will turn, but what if the motor is not meant to be driven by 12VDC?
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