Suspension Lowering

BigDingus · July 2, 2019

Hi folks.

My RX300 2004 has developed a fault where the rear left lowers to it’s lowest position a few minutes after start.

When I start the engine I can hear the pump run. The car raises to it’s height on all four corners, then this one lowers.

I’ve replaced the suspension ECU and checked all the sensors using a multimeter. All of them perform the exact same.

So i’ve concluded it can’t be either the ECU or the sensor.

Does anyone know what the cause could be or a solution to this?

To be 100% sure I was going to change the sensor, but they can be very expensive. I did find a cheap one for the right side, but I don’t know if the sensor is interchangeable.

NemesisUK · July 2, 2019

No leaks at connector to the strut?

BigDingus · July 2, 2019

I can’t see or hear anything.

If I move the sensor arm to trick it into thinking it’s low, the car doesn’t try to raise it.

BigDingus · July 2, 2019

What I also find strange is that it doesn’t run the pump to raise it again.

Herbie · July 2, 2019

Brush soapy water onto all air pipe and joints to see if any bubbles form anywhere.

BigDingus · July 2, 2019

I’ve now traced the pipe from the pump to the strut with no leak found.

Does anyone know what happens on a strut over charged. What I mean is, if you remove weight from the car and the car rises. How is the excess pressure released?

I assume there will be a solenoid and if so, where.

BigDingus · July 3, 2019

After much investigation I finally found a leak at the strut. Unfortunately I can only hear it. Soapy water doesn't show exactly where either.

So I'm going to take the strut off to examine it properly.

Can anyone tell me if there is a refurbish kit available?

PCM · July 4, 2019

21 hours ago, BigDingus said:

After much investigation I finally found a leak at the strut. Unfortunately I can only hear it. Soapy water doesn't show exactly where either.

So I'm going to take the strut off to examine it properly.

Can anyone tell me if there is a refurbish kit available?

I didn't think there was a kit, but ... recall a mention on here re: refurb.

Maybe 'do' a search on this forum ...?

The-Acre · July 4, 2019

23 hours ago, BigDingus said:

After much investigation I finally found a leak at the strut. Unfortunately I can only hear it. Soapy water doesn't show exactly where either.

So I'm going to take the strut off to examine it properly.

Can anyone tell me if there is a refurbish kit available?

I think any talk of a refurb or repair on an air strut is a non starter, I'd be looking at finding a used part if a new one was out of the question.

BigDingus · July 19, 2019

Guys I took your advice and got a second hand one which took weeks to arrive.

Lexus charge the same as a small house for one of these.

The bad news is. The part was fine but now I have a new problem.

I now have an RX300 2004 on which the suspension won't raise.
So I tested the relay which was fine (I have 2).
I then tested the pump by shorting the relay connections. Pump works fine.
I replaced the ECU for the suspention, but still the suspention won't run the pump.
I have diagnostic software but there is no fault showing.
I've removed the Battery power for 30 minutes. Then again for a few hours.
I've taken ALL of the level sensors off and cleaned inside them and also checked them by using a multimeter. All the values were the same.
I've checked all the connection to the sensors.

Still after all this, the pump won't run and I get a light on the dash flashing AFS (Automatic Froantlight Sensor)

Does anyone know of a solution?

BigDingus · July 20, 2019

I should have said. I have AFS flashing on my dash.

Only think I haven't checked is the over pressure switch on the reservior.

Now I need to find the tank.

Herbie · July 20, 2019

If the sensors are working then it would seem that the signal isn't getting back to the ECU.

I'd check all wiring for continuity because it sounds like there's a broken wire somewhere.

BigDingus · July 23, 2019

^{Hi Herbie.}

^{Having now checked all the cables, of which I think there must be millions, they all seem to be ok.}

^{I can see a car being sold soon.}

Herbie · July 23, 2019

Oh dear, that's not good.

May be a bit drastic to talk of selling though 😧

AFS is actually Adaptive Front Lighting System and as well as controlling the height and levelling of the headlights, it's what also makes them move left or right as you steer in those directions. I'm only clutching at straws here but are the lights doing their little 'dance' when you switch them on and do they actually move in the direction of steer as they should?

I'm just thinking that there may be some correlation between the lights and the pump, ie, if the lights don't move with the steering as they should, maybe the ECU prevents the pump from operating?

Other than that I can only suggest a trip to a proper auto electrician to see if they can sort it out.

PCM · July 23, 2019

Stupid question, but I assume the air suspension is switched on?

There's that TINY button low down near the driver's door...

BigDingus · July 23, 2019

PCM. If found out that switch was there early on. Why Lexus don't put it out the way beats me. It's definitley on.

Herbie. While following your suggestions I decided to have a more in-depth look at one of the sensors.

When I opened it up I discovered on of the gold coloured springs had some decay. While quite difficult to see I used some abrqasion to clean in. I probably missed it on the last clean.

Once put back on the car everything was perfect.

Once again thanks for everyone's input.

Cheers

Herbie · July 23, 2019

Woohoo!!! Glad you got it sorted Jon, well done!

PCM · July 23, 2019

32 minutes ago, BigDingus said:

PCM. If found out that switch was there early on. Why Lexus don't put it out the way beats me. It's definitley on.

Herbie. While following your suggestions I decided to have a more in-depth look at one of the sensors.

When I opened it up I discovered on of the gold coloured springs had some decay. While quite difficult to see I used some abrqasion to clean in. I probably missed it on the last clean.

Once put back on the car everything was perfect.

Once again thanks for everyone's input.

Cheers

BRILLIANT!

The-Acre · July 23, 2019

29 minutes ago, BigDingus said:

PCM. If found out that switch was there early on. Why Lexus don't put it out the way beats me. It's definitley on.

Herbie. While following your suggestions I decided to have a more in-depth look at one of the sensors.

When I opened it up I discovered on of the gold coloured springs had some decay. While quite difficult to see I used some abrqasion to clean in. I probably missed it on the last clean.

Once put back on the car everything was perfect.

Once again thanks for everyone's input.

Cheers

I'm really glad you sorted this, apart from your sheer joy at doing it yourself, it also helps the rest of us with air suspension to know how these very expensive sensors can be cleaned. Of course a main dealer would just replace them, in my case it would be around £350 just for the part! Well done.