P1651

[dave1]

Recently had O2 sensor replaced. Over the last 2 weeks the MIL has been coming on some days and not others. Code P1651 showing. Since this is intermittent could it be connected to the O2 sensors. Have tried various driving styles but nothing in particular seems to cause it. Hopefully not the VVAI but any info would be welcome.

[steve2006]

Was the replacement an OEM O2 sensor ? Was the MIL illuminating prior to the replacement being fitted?

[dave1]

OEM fitted (Denso). It was fitted because MIL was on but that was in September, 1,300 miles ago. OSF lamda was replaced and was only just outside tolerances.

[ColinBarber]

that code indicates a fault of the ACIS VSV. Nothing to do with the O2 sensors.

http://www.lexusownersclub.co.uk/forum/topic/51687-p1651-code/

[dave1]

Just wondered if sensor could cause it since from what I can find out for the code it should be when in excess of 4700 rpm that the valve comes into play? or am I misinterpreting things.

[dave1]

I had already downloaded your 3 PDFs but whilst the fault code is for the VVAI the circumstances leading to the code appear wrong.

[ColinBarber]

The ECU senses the voltage/current going through the VSV. I don't think it actually has to operate for the ECU to check. As your fault is intermittent I would check the wiring/plug at the VSV in case there is damage / corrosion.

Maybe the wiring was pulled/damaged when the O2 sensors were replaced?

[dave1]

That's a possibility I suppose....certainly worth checking. Is it possible to check in situ? Your input is appreciated. Only done 1300 miles in 6 months so seriously thinking of selling and sticking with 1 car now but I don't want to sell with any hidden faults.

[ColinBarber]

I'm not sure, you certainly cannot replace the VSV without removing the throttle body and inlet manifolds. I don't have access to a 430 so cannot check.

[dave1]

I'll have to get garage to check. Hopefully they will be able to check if it is loose or anything.