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Ride Height Control Modeule - No Communication. Error U0132

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32K views 10 replies 4 participants last post by  Raf  
#1 ·
Hello everyone. As you can probably tell from the post title, my 07 RRS has a U0132 error which my diagnostic tool reads as 'Ride Height Control Module - No Communication'. This is accompanied by the usual orange suspension light and 'Suspension Fault - Normal Height Only'. No other related faults on the code reader. So I know this error is common but everywhere I've read it is accompanied by a suspension failure of some sort. But heres the thing, my suspension works fine, at least for the first minute or so of driving. During that time it can raise and lower as it always had. This issue has plagued me for at least 1 year and a half. I don't think I have a leak as I haven't heard any hissing from the corners and I have no sagging. I rebuilt my compressor a year or so ago with the kit from x8r. The fault appeared before that and I thought that might fix as I couldn't find any other issues. Last week I replaced the compressor with a new Hitachi (less than $150 so what the hell) because I found that despite the rebuild, which included new desiccant and new seals, it was clogged from moisture turning the desiccant to power. The bracket holding it to the chassis had also entropied into its component molecules and the compressor was only held on with only 1 of 3 bolts, the hoses and the plastic housing. So the mounting bracket has been replaced too, along with the compressor, but this fault still remains. Its nothing more than a nuisance as i can clear the fault and it clears itself at each turn of the ignition key. I don't think its a ride height sensor because the little red squares on the console display seem to reflect the actual position of the suspension. What else am I missing given the fault has carried on for so long without any other symptoms or failures?
 
#4 ·
So one added piece of the puzzle I just noticed. If the car is started and then i drive off at normal height the fault is triggered very quickly - about 10 secs. But if I start to raise the suspension then the fault doesn’t occur until about 10 seconds after the ride height is met, It rises quite slowly (not sure what the norm is), tasking around 45 seconds. So why dont I get the fault while its raising? This is a clue what I don’t know what to means. Maybe the ride height control unit has different fault tolerances when sitting idle than it does when being demanded to do something?
 
#5 ·
Take it for a drive and drive it under 10km (~6ish? M/hr) see if it triggers. I had a similar issue caused by a faulty pressure sensor in the abs unit. The vehicle would not fault in reverse or below that speed. Also, take the console apart and check for liquids getting into the module or wires.
 
#6 ·
Thanks Aaronv09 , you are certainly on to something here. As you guessed, I don't get the fault until I start to drive over 6-ish mph. If I just sit there it doesn't trigger the fault. If I start to raise the suspension, drive over 6mph while its raising I can delay the fault for a while but it will come on about 20-30 secs later.
I will take a look at the EAS ECU which I believe is in the foot well somewhere. I will also have to research the pressure sensor for the ABS system as I am not familiar with what sensor you are referring to.
 
#8 ·
Thanks. Decided to read through your whole post and wow, that was a journey! So you think the issue may be the ABS module? I see from your post that the ABS module has to be replaced as a unit. I dont want to jump into replacing it just yet, as you know it could end up being a bad wire someone along the line. Quick sside story; I've certainly had water in the car footwell because the shop I bought the car from left the windows down between me deciding the buy it and returning with the cash the next day. They didnt tell me and I went down the rabbit hole of thinking it was bad sunroof drains. That was a couple of years ago. Still, wire corrosion is a possibility I cant ignore and will be **** hard to find.
So question this leaves me with is how do I look into this further? If its an ABS sensor issue would I not get a fault on a scanner? I'll certainly check it with the RSW software but I dont recall seeing anything on my handheld scanner tool that I used to come up with the original 'U0132 no communication with ride height control module'.
 
#11 ·
Thanks. Decided to read through your whole post and wow, that was a journey! So you think the issue may be the ABS module? I see from your post that the ABS module has to be replaced as a unit. I dont want to jump into replacing it just yet, as you know it could end up being a bad wire someone along the line. Quick sside story; I've certainly had water in the car footwell because the shop I bought the car from left the windows down between me deciding the buy it and returning with the cash the next day. They didnt tell me and I went down the rabbit hole of thinking it was bad sunroof drains. That was a couple of years ago. Still, wire corrosion is a possibility I cant ignore and will be **** hard to find.
So question this leaves me with is how do I look into this further? If its an ABS sensor issue would I not get a fault on a scanner? I'll certainly check it with the RSW software but I dont recall seeing anything on my handheld scanner tool that I used to come up with the original 'U0132 no communication with ride height control module'.
Same problem here on a 2006 L320. Have the same amber warning light after taking the trk to the car wash. Leak is on the passenger side, just this am, looked for a sunroof drain on that side and found none, therefore I concluded that water got in through the cowell, which is pretty deteriorated on that side as well. I raised the trk up and left it up to see if leaks 'manifest'. Thinking of taking it to the shop to see if they can erase the warning light or calibrate the cumputer. This happened to the trk a few years back on the drivers side when the sunroof drain leaked onto the floor mats, all they did was reset the computer at a cost of about $450
 
#9 ·
The no comm. Confuses me and I would focus on that even though based on my experience I would look closer at the abs... Hmm. I believe you can check the abs module live data and look at the abs motor and pump relay... That's what turned me onto the pressure switch being faulty. One was on and the other was not. But this was causing an EAS fault with "invalid data from ABS"
I would be looking under the console, the rotary dial (ride height module) wires may have had a coffee spilt and gotten into it or something.
What happens if you clear the fault while the car is running?
What happens if you enable/disable DSC and/or HDC?
The RHCM, I believe is a slave module to the EAS, meaning no modules directly rely on it to function. This explains why EAS works. But it does control hill decent which is wired in series with traction control which are functions using the EAS and ABS. Some data, once you start moving is causing the module to crash...

These comm problems can be very frustrating to chase down because it can be invalid data from any other module causing a different module or the entire network to crash. I wouldn't spring for any new parts just yet until you are quite positive on the problem.