Like many visiting this forum I've had the stiff ride issue with my 2005 gx470. Took it to three lexus dealers and finally the vehicle is fixed. Hats off to Lexus of Maplewood, St Paul, MN. Their shop foreman persisted and found after several days troubleshooting; a speed sensor was the culprit. Anyone else have this issue. My ride is much smoother over speed bumps without the need to cycle through the height adjustment.

 

Please explain.

 

I was advised by the service manager the acceleration sensor (Part # 89191-22020) was erroneously sending a message to the rear suspension to stiffen, even when I was driving under 20 mph. I'm told this sensor is supposed to stiffen the ride as the vehicle gains speed. Replacing the sensor has resulted in a definite ride improvement, so I hope this holds. Lexus of Mobile replaced the shocks (no change). Lexus of Palm Beach was not able to find any problems (though in fairness to them, they tried but needed add'l time to troubleshoot).

Big thanks to Todd (Shop Foreman) for his persistence in solving this mystery, and Mike (Service Advisor) for hearing me out.

Note: My experience at Lexus service departments have always been great!

 

Wow! Sounds legit. I'm getting right on this. Thanks!

 

How much was the speed sensor job?

 

How much was the speed sensor job?

 

That is very interesting. Thanks for sharing.

 

Covered under warranty (cpo), but the invoice shows the sensor at $796.00 plus R&R cost at $116.00. I no longer have to cycle through the height adjustment for a decent ride over those speed bumps. Hope ths works for others.

 

how did the scan tool not pick this up if the problem was a sensor? they shouldve spotted this problem instantly. i wonder how they finally decided on the speed sensor?

 

Good point about scanner not hitting on the sensor. The dealership had the gx for 4 days troubleshooting. Initially, the service rep said they found nothing wrong. I asked the shop foreman, to drive my gx; he agreed with me on the abnormality of the harsh ride issue. Persistence paid off once again...

 

$790 for a sensor is outrageous. It's a little bit cheaper @ Sewell for $583. At that price it makes it impossible to diagnose DIY if it doesn't output any error codes.

It looks like that part number is from an GS and not a GX. The GS part is slightly cheaper then the GX, so at least it's good to know they are compatible give your experience.

 

Ok Playtobias.Since Dealer has replaced the sensors which you mentioned, GX have three built in One for the Front and two for the rear, Obviously the rear is what seems to be replaced.
The Acceleration Sensors function is to detect the up and down accelration for the vehicle. The acceleration sensors 3 in total are mounted in the suspension ECU which is the left side of the cowl and in the rear Quarter area and the detects the up and down acceleration of the vehicle. fyi

 

How/why does this affect the ride quality? My truck has the same issue. Although mine seems to ride stiff but not bottom out on the sport selection of the shock settings, comfort gives a boaty ride and bangs when going over speed bumps

 

My service tech explained in my case the sensor was improperly communicating with air suspension components resulting in the stiff ride at slow speeds. Safe to say this may not be an issue on other gx470s with similar symptoms. Would not hurt to rule the sensor out though.

Thanks mann777 for the explanation.

 

Chris, you and I seem to have had the same bottoming-out sensation issue. Did you try the speed sensor fix as mentioned above? If so, did it resolve your issue?