Ls430 engine management light

[Barry1000]

The engine management light came on so I took it to Lexus who said that it was the sensor that balances the smooth running of the two V’s.  I asked them what effect this would have and they said the engine would run less smoothly and be less economical.  I have monitored the mpg over the last few months while the light has been on and see no change in the economy and the engine performs as smoothly as it ever has.  The problem is that to fix the sensor is very expensive as it is at the bottom of the V and would involve taking the head off and Lexus said it was about 5 hours work and probably about £1500.  I see little point in fixing this as the car performs perfectly but it is annoying to have the light on all the time and also if another error pops up I will not know because the light is on all the time.  Is there any way of stopping this error tripping the light as it does not seem to be a true error?

[royoftherovers]

Not fixing it Barry, might lead to an MOT failure  ?

I do sympathise with your problem however.

[gdh300]

If it isn't affecting emissions - which sounds like it wouldn't - then possibly you can clear erase the error to get it through the MoT.

I had a recurring P0430 error on my 2001 IS300 (even after fitting of the oxygen sensor) for about two years, and emissions were never a problem at MoT time. I used a cheap Autel ODBII scanner to erase the code on the morning of the day and knew if would be off for at least 50 miles/an hour, so ample time for the garage to complete the test. 

[ColinBarber]

Do you know what the actual error code was Barry?

[messi]

I think I know what it is. It's the vsv valve, common failure in the 430 engines but it won't affect anything really. But the part is around £52 from lexus dealers and it's about 4 hr job, when I had the ls430, lexus quotes me £400 odd to replace it. I'm not sure where the Lexus dealer you went to got a figure of £1500 from, clearly they are trying to rip you off, it's not Lexus woodford by any chance?

[Tinonline]

Recommend you speak to a non Franchise garage.

[Barry1000]

Thank you for you replies.  The error code is P1651.  Has anyone had experience of a non lexus dealer fixing something trike this?

thanks Barry

[sorcerer]

A search on Google for "Lexus P1651" (without the quotes) returned this:

pdf file for P1651

[Tinonline]

So it’s the throttle body sensor or MAF?

[ColinBarber]

Just now, Tinonline said:

So it’s the throttle body sensor or MAF?

No the ACIS valve - or the Vacuum Switching Valve that controls the ACIS. Check its connector, then replace the valve.

When the valve opens it shortens the airflow distance into the engine, allowing maximum power. With the valve closed the air has to travel a greater distance which improves low end torque.

If you didn't want to fix it you could probably use a resistor to simulate the actuator's coil so the ECU doesn't detect an error.