Air suspension problems

[mobileboat]

Hello all,

First post. Would be grateful for you opinions. I have had a look at the previous posts on air suspension problems and they have been useful. I know that the air suspension system is complicated and people may not be able to give specific advice, but any advice is helpful.

My 56 plate RX350 has 200,000 on the clock. I had all 4 height sensors replaced in 2014 at 156,000 at the dealers. Recently the off light on the air suspension came on temporarily and then disappeared. Following day all 4 corners of the car were lowered. The compressor makes no noise at all. The air suspension light moves from N to H but there is no change in the suspension. The ride of course is terrible.

The 2 fault codes showed C1742 (compressor motor) and C1751 (continuous current to compressor motor) at a independent garage. The garage told me its either the "relay" or "compressor". Not sure which relay they specifically meant.

Not keen to take car to dealers as any repair cost by them would be worth the cost of the car.

Keen to keep the car.

Anyone have any advice on best course of action?

Thanks in advance

Kind Regards

John

[ChrisKaye]

Hi John,

Wow, that's some mileage there :)

Those error codes can easily be triggered if one or more air struts are leaking air.

Not something you will find out using a non-Toyota/Lexus code scanner tho (Techstream).

Whereabouts are you located in the country?

If you could call around and find a mobile techie that can read all the codes then they can tell you which (if any) struts are not holding air; I saw on eBay a seller is currently selling new air struts for about 33% cheaper than Lexus, if that helps...

I had exactly the same symptoms as you and turned out to be a moderate leak in the near side rear strut and a smaller leak on the offside front strut, I was able to change both using a socket set, vice grips and the RX jack (and £3 fuel line release tool set from eBay) on my driveway.

The reason the compressor codes are thrown is if the compressor runs continually for more than 30secs without the height of the car stabilising within preset parameters - the car computer disables the compressor to protect it from over-heating and throws the codes.

Erasing the codes (or disconnecting the Battery for 15-30mins) is a quick way to clear the codes and enables the compressor to run again until the computer shuts it off to protect it - this is the easiest test you can perform to see if the compressor is still good.

When I did as nursing mine along, I'd reset the codes, start the car and count to 15, then using the hidden button under the steering wheel, disable the air suspension for 3 seconds and then re-enable it (trying to avoid going beyond the 30 second limit) this allowed me to get some ride quality back for short trips until I got all the parts to do the strut change.

Fortunately I had access to Techstream to help diagnose which struts were to blame; but once you have air back in the system you can usually tell which corners are sagging...

Good luck!

Sent from my Iphone using Tapatalk

[mobileboat]

Thank you for your detailed response Chris. Will try tomorrow and will post how i get on. Have had to drive car on short journeys without suspension active. Unpleasant to say the least. Hope that has not done too much harm?

[ChrisKaye]

If your sensible there won't be any lasting damage.

Without air in the struts, when a wheel bottom outs on a pothole or bump, the top of the strut hits a heavy duty plasticy/rubbery bung designed for taking knocks.

The longest journey I did was from Windsor to Dorset with mine playing up, all you can do is avoid as many bumps as you can!

The worst bit with a bad strut is that it feels like the tracking is off and the car pulls to the left or right, increased tyre wear and the car feels less sure footed when braking or going around tight turns, so leave plenty of space between you and other cars.

Sent from my Iphone using Tapatalk

[mobileboat]

Thanks Chris. 

Tried the above procedure with disconnecting the Battery. I did not hear the compressor, but then again are you supposed to? Prior the suspension failing I was able to hear the compressor whirring away. At times it sounded pretty manic, maybe that was a sign that I ignored. I looked at each strut, both the fronts did not move at all. The rear may have moved marginally but to be honest I am not 100% convinced.

I'l try and chase up what the machine name is. Unless it is obvious from the attachment (pardon my ignorance). Is there anyone in Birmingham with Techstream other than dealers?

Not sure where to go from here....

[mobileboat]

It looked like the above. The mechanic said there is no air leak. He did not look at the struts etc on a ramp. Not sure how correct the info given is. I have started looking at other cars which is a bad sign....

[mobileboat]

Thanks for info. I suspect you need tutorial in how to use it. It may be beyond my competence.

Will probably need to take to a independent who knows their stuff before I decide whether the car is going to the graveyard.

Anyone know of any reputable independent in Birmingham/West Midlands?

 

[stringbender]

20 hours ago, mobileboat said:

Will probably need to take to a independent who knows their stuff before I decide whether the car is going to the graveyard.

Have you checked with your local Lexus dealer how much they'd charge to replace the compressor ? Mine hasn't packed up yet (2005) but I can tell the compressor is running much more than it used to do so it won't be long. I've also had a look round at other cars and haven't yet found one that has as much kit as I've been used to for all these years. Your car is younger than mine so it's way too soon to go to the graveyard. This is a really interesting thread for all us SE L owners so keep us informed of how it pans out. Decades ago there was a guy on here who stripped out his Lexus compressor and put in a whole new system -  by himself ! Pipes and all. Sounds like Chris Kaye to me ! Wish I was able to do that as my car is going better than ever and, like you, I dread to think of it going to the graveyard.

Alan

 

 

[mobileboat]

In a ideal world I would not want to dispose of the car. Compressor £1922 from Lexus - part only.

I have seen them on sale £680 on eBay. 

However need to know exactly what's wrong before splashing the cash which is why I am seeking guidance 😀

[stringbender]

Ouch !! That's way more than I was thinking ! There was a thread on here recently about coil overs and reverting to springs. have you given that any thought?

[mobileboat]

Yes I have given that some thought.

The only parts needed are the 4 coil springs and 4 shock absorbers? Is that correct?

I am having difficulty getting prices on these parts. I can only find a company called Arnott who sell them. Will contact them on Monday.

[PCM]

I think you need to get the problem clearly diagnosed first.

it could be as simple as a corroded earth ?

Who knows...