I've had the same problem talking to my '98 LS400 Mk4. My research came to the following conclusion:
On a UK LS400, the port that looks like 'ODB-II' under the dash is not in fact 'ODB-II'. It is referred to by Toyota as 'DLC3'. It is possible to interrogate the ECU using the following method from the Celsior manual (it works on my '98, anyway):
- Place car in Park, ensure A/C is off
- Short between pins 4 and 13 on the connector socket (as per picture) - you can use a paperclip
- Turn ignition switch to 'ON' (do not start the car). 'DIAG' is displayed on the LCD display below the speedo
- Press the 'Function' button on steering wheel once - display changes to 'EFI'. If there are any EFI warning codes, it will then display 'EFI NG' and any codes in sequence; otherwise 'EFI OK' is displayed. If 'EFI --' or 'EFI E' appears then the ECU may be partially dead.
- Press the 'Function' button again - display changes to 'VSC' - this will display the codes for VSC (if any) in the same manner
You can use Google to find lists that will tell you what the fault codes mean.
Mk4 LS400 - Code reader won't connect to car - Has anyone on here successfully connected one to a UK LS400?
in LS 400 / Lexus LS 430 / Lexus LS 460 / Lexus 600h / Lexus 500h Club
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Hi there,
I've had the same problem talking to my '98 LS400 Mk4. My research came to the following conclusion:
On a UK LS400, the port that looks like 'ODB-II' under the dash is not in fact 'ODB-II'. It is referred to by Toyota as 'DLC3'. It is possible to interrogate the ECU using the following method from the Celsior manual (it works on my '98, anyway):
- Place car in Park, ensure A/C is off
- Short between pins 4 and 13 on the connector socket (as per picture) - you can use a paperclip
- Turn ignition switch to 'ON' (do not start the car). 'DIAG' is displayed on the LCD display below the speedo
- Press the 'Function' button on steering wheel once - display changes to 'EFI'. If there are any EFI warning codes, it will then display 'EFI NG' and any codes in sequence; otherwise 'EFI OK' is displayed. If 'EFI --' or 'EFI E' appears then the ECU may be partially dead.
- Press the 'Function' button again - display changes to 'VSC' - this will display the codes for VSC (if any) in the same manner
You can use Google to find lists that will tell you what the fault codes mean.
I hope that helps!
Dan