Hello Everyone,

I haven't made time to get some proper pictures of a new to me 2001 LS430 UL with 102,000 miles on it. The car has spent its life in Arizona and is in fantastic shape, I'm really pleased to have found it. Prior to this I was an LS400 / LS430 / LX470 guy, I've come back to the LS430 and happy I did.

As I've been changing fluids, filters and polishing things I haven't really found any issues. The car rides and drives just as you'd expect.

Because of another car in my garage I finally broke down and bought an Ancel FX6000. Out of curiosity I connected it to the LS430 and only found one ECU with codes: Air Suspension ECU. I've cleared the codes and they return instantly.

DTC Codes Present (Current):

• C1781 - Steering Sensor Circuit
• C1782 - Stop Light Switch
  • Test tool shows this is functioning / brake lights work
• C1783 - Door Courtesy Switch Circuit
  • ​​​​​​​Each door correctly reports Open / Closed in the dash
• C1786 - Height Control Switch
  • Test tool shows this is functioning in both positions / Car does raise and lower
• C1787 - EMS Switch Circuit
• C1794 - RH Front Wheel Speed Circuit​​​​​​​
  • ​​​​​​​​​​​​​​If this was bad I'd be having ABS issues, correct?

I've read the diagnostic procedures for each of these codes and they basically come down to four things:

• The sensor / switch is bad. In this case each of these things seem to work / be feeding information
• The Skid Control ECU is bad
• The Air Suspension ECU is bad
• The connection between the Skid Control ECU & Air Suspension ECU is bad

I believe I've ruled the individual sensors out, I'm now looking at the Air Suspension ECU or the harness that feeds it. The only modification to the car is both front air shocks were replaced with Arnott units shortly before I got the car. They seem to function as expected.

Does anyone have experience with this combination of codes?

Any help or thoughts are appriciated!

Sunseek

 

Hello Everyone,

For anyone looking at this in the future, here is the outcome of my journey...

The DTCs that I was reading came via an Ancel FX6000. While an amazing tool for the money it gets a few things wrong with Lexus / manufacturer specific DTCs. I got a Mini VCI USB OBD2 diagnostic cable and the software you'd get to really dig into things, turns out when you're chasing DTCs you want to be using manufacturer specific tools.

After going through all of the modules in the LS I'm happy to report I have no DTC codes pending or stored. I was able to get feedback from each of the sensors and in some cases run module specific tests. Turns out the Ancel was incorrectly reporting DTCs.

One other thing to note, if you do indeed have problems with the sensors I've got listed above, you'll know.

With a fair amount of German and Italian cars in my life it's crazy to have a car with zero codes of any kind in it. Lexus is the only brand I've ever owned that can go years with a totally clean slate and no DTC / MIL codes.

Hope this is of help to someone.

Sunseek