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Ask Skyvisions Your Own Question
Skyvisions, ASE Certified Technician
Category: Lexus
Satisfied Customers: 14505
Experience:  Lexus Expert
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I have issues with my Rx450h which continuously has

Customer Question

Hi. I have issues with my Rx450h which continuously has dashboard lights on however the car is driving absolutely fine
JA: Have you checked the fuses? The dashboard bulbs?
Customer: Yes. All ok
JA: What is the model/year of your Lexus?
Customer: RX450h Hubrid 2010
JA: Are you fixing your vehicle yourself? What have you tried so far?
Customer: tried computer diagnostics and it prompted with various issues. Lights that are continuously on are TRC, ABS, VSC, Hand brake, check hybrid system, check Air suspension system, Check brake system
JA: Anything else you want the mechanic to know before I connect you?
Customer: One expert asked me to change the ABS/VSC/TRC ECU which i did but the lights did not go - dont know whether it needs re-initialization thats it
Submitted: 2 months ago.
Category: Lexus
Expert:  Skyvisions replied 2 months ago.

Do you have a code reader to check for codes that would be set in the ABS computer of the VSC computer or the traction control computer?

Customer: replied 2 months ago.
it is giving following codes - C1203, C1345, U0073, U0293, U0126, U0129
Expert:  Skyvisions replied 2 months ago.

OK let me do some looking into this. Do you have the VIN available? Who told you to replace the VSC Computer? Has this been to the dealer?

Customer: replied 2 months ago.
VIN is JTJBC11A202030972. Diagnosis was a by a local Lexus Expert.
Expert:  Skyvisions replied 2 months ago.

Ok give me some time and I will get back to you with some ideas.

Expert:  Skyvisions replied 2 months ago.

The codes that you getting are the same as before the computer was replaced? Was this computer a new Lexus computer or used?

Customer: replied 2 months ago.
they are the same. which makes me think if it needs to be reinitialized (or coded to the car) . It is a genuine used item from another car fully working and under warranty.
Expert:  Skyvisions replied 2 months ago.

OK did you install or did your lexus expert? Do you have the part number of the Computer and are you looking for specific repair guide lines or general information?

Customer: replied 2 months ago.
Hi. We installed as we thought its a plug and play part. SO dont really know if it needs any initialization or mapping/programming. The ECU/Computer is called ABS&TRC&VSC ECU and part no is 89540-48421 and serial is(###) ###-#### I am looking for an expert opinion on whats wrong with it and how we can go about resetting the codes - if it has to do with this ECU i mentioned, will it need programming and how ?
Expert:  Skyvisions replied 2 months ago.

Ok Standby. Little busy in the shop and I need to do some research on this. Thanks for the extra info.

Customer: replied 2 months ago.
Sure. Need an expert opinion and your thoughts what else could be wrong as I think it could be very simple wiring or electrical or programming issue as these all lights are pretty much related while the car is driving/working absolutely fine. Note the lights that are continuously illuminated on dashboard are ABS, Traction, VSC, Hand brake, Warning Sign, Check Hybrid System, Check Air Suspension, Brake System Failure,. So pretty much all lights are on.
Expert:  Skyvisions replied 2 months ago.

Okay here's what's going on. First of all description of the codes. The C1203 code means there's a communication error or failure between the engine control computer and the ABS computer a lot of times this code was set by default whenever there is an engine code set in the engine control computer. However it will also set if the linear offset solenoid has not been initialized or calibrated. Given your situation you also have a C1345 code which specifically says that the calibration of the linear solenoid has not been done. Those two code should clear up once the solenoid has been initialized or calibrated that has to be done whenever the vehicle skid control computer is replaced. However my more pressing concern is all of the communication codes that you have. The U0126 means there's no communication with the steering angle sensor the U0129 means there's no communication with the skid control ECU and the u0293 means there's no communication between the HV ECU and the skid control computer. The U0073 means the control module Bus off signal is not present. That could be set by default due to the other communication error codes. The first thing to do is initialize or calibrate the linear offset solenoid. Click this link and download that procedure using the jumper wire method if you do not have a Techview scan tool. Make sure you save a copy the link will time out. Once you perform the initialization procedure remove the negative battery cable and positive battery cable place a jumper wire between the two cable ends isolated from the battery to do a hard reset and memory clear. Then reattach the battery cables drive the vehicle and see if the same codes come back. As a backup or checked to make sure that the offset solenoid calibration occurred I would reperform the calibration procedure after you reattach the battery cable ends. Back to the communication function codes. You need to check the high-speed can network and make sure it has 62 ohms at the DLC three connector. Then you need to isolate the vehicle skid control computer and make sure it has the proper resistance on the network. Check for power and ground to the skid control computer if you confirm that the high-speed can network is working and checks okay and the HV ECU and skid control ECU are both on the network and communicating then the initialization/calibration should solve the problem it's just that I've never seen this many communication error codes caused by just one initialization calibration problem. Hopefully that takes care of it and you're not getting into a high-speed can network diagnostic problem. Your Lexus expert should how to check the high-speed can network to the skid control.