RobertOl

Hi everyone,

I noticed my 2005 GX470 started to "bottom out" when going over speed bumps or potholes. The air suspension seems to work fine raising and lowering ok and the general ride is still quite smooth. From some simple searches on the board it would seem that leaking of the air suspension could be the problem?

I did a code read and got the following error codes none of which sem related to the problem. Anyone have any experience with these codes and have a course of action?

Code
CO200 Right front speed sensor malfunction
C1223 Malfunction in ABS control system
C1340 Open circuit in central differential lock signal
C2172 tire pressure, transmitter identification number not registered

mann777

Robert, From what the original problem you have quoted about the ""Bottoming Issue"", and the error codes, They are not related to each other at all/
First the Bottoming Issue,the GX model many owners had this issue, some have gone and replaced the shocks and some just the sensors. Since you have quoted the Compressor for the air suspension is working fine ( the leak is ruled out) , I would want you to look at the Height Control Sensors and have them cleansed with some Spirit or Alcohol. These tend to die fast due to absorption of moisture intrusion and sea salts. Now this is not a fully complied solution,but one way to troubleshoot and solve the problem.( pm me your email will send you the location / diagram)
Now coming to the error codes
The First two codes are interrelated.( will send you a detailed diagnostics ) pm yr email
The Third code, will send you the diagnostics
The Fourth Code - The TPIS has lost link with the ECU, all you need to have the unique Transmitter VALVE IDs numbers stored back into the ECUs. these are manually entered using the Techstream Toyota Scan tool via the Dealers only and some can do it using the private scan tool which could access the Lexus/Toyota ECU and have them entered.

Or final one way is give your truck for service ( regular oil/ filter change ) and the dealer would have them all reset and delivered.

RobertOl

Thanks for the reply man777,

Here is an update. I had the car in a friends shop to work on some of these issues.

CO200 Right front speed sensor malfunction
C1223 Malfunction in ABS control system
-We decided to start by thuroughly cleaning the right wheel speed sensor. It appearantly did the trick becuse after a test drive we could not trigger the code and 2 days later the code has still not appeared. Previously it appeared as soon as we turned the car on after clearing the codes.

C1340 Open circuit in central differential lock signal
-This code also went away but we are unsure if it just hasn't been triggered or if it was related to the first two codes.

We had the car up on the lift to inspect the suspension system and noticed that the left strut was leaking (significantly, slight leakage from the right strut. It was causing the car to sit 1/4 of inch lower on the left side. Changing the suspension to sport definately tighened the suspension and prevents the bottoming out. We do not have any issues with erradic height adjustment as seems to be the case when the height senser is malfunctioning. So we are now looking into whether to change the two existing struts or do the full spring conversion kit. It seems the suspension system is working with the exception of the leaking struts.

C2172 tire pressure, transmitter identification number not registered
-We have not tackled this yet, but we'll see if the scanners in the shop can reprogram it.

I'll update as we proceed. Thanks for the input so far.