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Skyvisions, ASE Certified Technician
Category: Lexus
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Experience:  Lexus Expert
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Lexus GX470: Hi I have multiple codes on a 2005 lexus gx470

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Hi I have multiple codes on a 2005 lexus gx470 C1253,C1241,C1223,C1201,P0420, im not sure if they are all related because I looked into it and I wonder if its the ecm???
Thank you for choosing JustAnswer and allowing me to help you resolve your Lexus questions! If you clear these codes do the same codes come back altogether?
Customer: replied 3 years ago.

Yes all the lights and the codes

Customer: replied 3 years ago.

Yes if i clear them they come back on after driving it for 10 mins


Customer: replied 3 years ago.

Did you get my response?


Yes I am still here. I'm processing all the codes to find out a common denominator. Standby this will take a little bit of time.
Customer: replied 3 years ago.

Sorry, new to this just signed up.


Are you a shop or private owner? How much detail are you looking for and are you looking to repair this yourself or looking for general information so you can have this repaired as an educated consumer?
Customer: replied 3 years ago.

Im a private owner and I do most of my own work.

Okay here goes. The P0420 code is a catalyst efficiency code. This is not a sensor related problem it strictly means that the efficiency of the catalytic converter is failing. This particular code is for bank one which is the driver side bank on the 4.7 L engine. When this malfunction occurs it by default sets code C1201 in the vehicle skid control computer because it monitors the engine control computer for malfunctions for safety reasons it shuts down the vehicle skid control system. The C1223 code set in the vehicle skid control computer when it sees a malfunction in the ABS computer. The C1253 code means there is a malfunction in the Hydro boost pump motor relay or circuitry. This code could be a false code due to the C1241 code. The C1241 code means that there is abnormal voltage to the skid control ECU. The primary fuse that is monitoring or the voltage is terminal IG1 at the skid control ECU and this is powered up by the ECU – IG fuse. This fuse is located in the driver side junction block. Pop the cover and locate this fuse and check it for voltage and if it is blown. In order to test the pump motor and relay for the ABS system it is necessary to have access to a wiring diagram and the flowchart which gives you step-by-step pin voltages. That is a bit much for this type of format. If you would like a link to the Toyota website you can purchase a two-day subscription and go through this step-by-step to isolate and diagnose the problem completely. You can also download and save just about any information you would want or need for this vehicle. If you need any further assistance you can reply and I can guide you through those steps.
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Customer: replied 3 years ago.

Thanks for the info, if the voltage is high at the ecu fuse what would that mean?

Provided it is not over 14 V it should not be an issue. If it runs higher than that then you're getting into an alternator or charging related problem. If you are going to do your own service work I recommend that you check this website out. It is not free but this is the site the Lexus and Toyota guys use. They normally charge $15 for a two-day subscription and you can download most anything you need. The website is

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