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M & S lights flashing

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Old 10-18-2011, 10:40 PM
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Angry M & S lights flashing

The other day my M & S lights began flashing and the transmission went into limp mode. It is an intermittent problem, sometimes it does it and sometimes it doesn't. I read the codes and got a P0750 (Shift Solenoid A malfunction). I checked the battery, less than 6 months old, and the alternator and they both seem to be fine. I also checked the interlock solenoid in the console and it seems to be also working fine. I hope it's not the xyz switch not only because it is expensive but because I had it replaced 2 years ago under an extended warranty. What do you people think it could be, I am totally lost on this one.
 
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Old 10-18-2011, 11:45 PM
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Here is some RAVE on the tranny and M&S:

While the ignition is on, the EAT ECU diagnoses the system for faults. The extent of the diagnostic capability at any
particular time depends on the prevailing operating conditions, e.g. it is not possible to check torque converter lockup
while the vehicle is stationary, or to check for a short circuit to earth if the circuit concerned is already at a low
potential.
If a fault is detected, the EAT ECU immediately stores a fault code and the values of three operating parameters
associated with the fault. Depending on the fault, there are four possible effects:
l
The fault has little effect on gearbox operation or vehicle emissions. The driver will probably not notice any
change and the warning lamps remain extinguished.

l
The fault has little effect on gearbox operation but may effect vehicle emissions. On NAS vehicles, if the fault is
detected on a second consecutive drive cycle, the MIL illuminates.

l
All gears are available but kickdown does not function. The sport and manual warning lamps flash. The MIL
remains extinguished.

l
Limp home mode is selected and vehicle performance is greatly reduced. The sport and manual warning lamps
flash. In all markets, if the fault is detected on a second consecutive drive cycle, the MIL illuminates.
After the detection of a fault, the effects remain active for the remainder of the drive cycle. In subsequent drive cycles,
as soon as the EAT ECU diagnoses the fault is no longer present, it resumes normal control of the gearbox. The
conditions required to diagnose that the fault is no longer present depend on the fault. Some faults require the engine
to be started, others require only that the ignition is switched on.
After a fault has not recurred for forty warm-up cycles, the fault is deleted from the EAT ECU memory. Only five
different faults can be stored in the memory at any one time. If a further fault occurs, the fault with the lowest priority

will be replaced by the new fault
 
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Old 10-19-2011, 12:17 AM
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Thanks, I am actually in the process of downloading the Rave as I type this post.
 
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Old 10-19-2011, 04:34 AM
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I don't use the RAVE main screen, but I go straight to the pdf main file, and the directory for the particular truck. Once in there, any of the files can be opened as a pdf, and they can be searched for a term, like P1535, and software will find every place that appears. You can use a freeware program, like pdf4free, to "print" the pages to a smaller pdf that you can add to posts, etc. Also, you can carry the RAVE on a USB drive, in the truck and to the office, etc. If in the truck, you may find yourself at a repair shop one day, and it helps to have the real deal with you.

The RAVE has lots of areas, like overhaul, electrical diagrams, workshop manual, entertainment, navigation, owners manuals, etc.
 
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Old 10-19-2011, 05:29 PM
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Thanks for the advise. I am actually going over the Rave right now.
 
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Old 10-19-2011, 07:01 PM
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sounds like the xyz is bad. u live in florida. my guess is you use the air con often. the drain drips directly on the xyz. so unless they rerouted the drain out very well could have failed again. it can be rebuilt. it's a mechanical switch. it fills with water and contacts become soiled.
 
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Old 10-19-2011, 07:19 PM
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Originally Posted by hilltoppersx
sounds like the xyz is bad. u live in florida. my guess is you use the air con often. the drain drips directly on the xyz. so unless they rerouted the drain out very well could have failed again. it can be rebuilt. it's a mechanical switch. it fills with water and contacts become soiled.
Thank you for your help. Is the rebuilt a Do it yourself thing? Can it be opened up dried and the contacts cleaned or is it a sealed unit. I would hate to have to buy a new one, they cost $640 and the last one apparently only lasted 2 years.
 
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Old 10-19-2011, 07:39 PM
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Take a look at these pages from the RAVE:

switch and wiring diagram, in the right place to cause the most problems electrically if wet. Six switches inside one housing. It is possible to read it from the connector for testing.
 
Attached Files
File Type: pdf
xyz 1.pdf (436.5 KB, 397 views)
File Type: pdf
xyz 2.pdf (1.27 MB, 352 views)
File Type: pdf
xyz 3.pdf (686.0 KB, 308 views)
File Type: pdf
xyz contacts.pdf (660.7 KB, 304 views)
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Old 10-19-2011, 07:41 PM
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I thought I saw part only for like $125. I suspect it can be refurbished by a careful DIY, it was made by human hands, not robotics.
 
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Old 10-19-2011, 07:49 PM
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Savannah, thanks for the links. I started looking at the Rave today for the first time and it was so interesting and knowledgable that I started reading other things and never got to the transmission section. I will check the switch for continuity tomorrow if it finally stops raining. It has been raining since friday. I also have to check my SLS, change the oil, and rotate tires.
 


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