Fault code P1426 IS220D

[Lexuspete2]

I wonder if anybody can help

I've run onto the dreaded VSC light on problem.(P2002).  Cleaned EGR and changed oil (magnatec C2) and been for a couple of long runs.  Had a few problems with dpf clogging in the past and this has always cleared them after Lexus engine rebuild in 2011.  Appears to be running fine but VSC light very persistent.

The fault code has now changed to P1426.  I have found it all but impossible to find out what this code means for an IS220D.  Other cars yes, Lexus no.

Any help greatfully received

I've owned the car from new and its covered 135k

[iwonder]

Have you touched any hoses to dpf or connectors for pressure differential sensor.

[Lexuspete2]

Thanks for your comment

The connector was inspected after the fault code reading.  The local very good garage did think the code was to do with the differential pressure sensor as you suggest but confirmation is difficult to find

The last time the bonnet was opened was when the egr valve was cleaned.  This is quite a way from the pressure sensor.

I did wonder if after any carbon from the cleaning got in to the engine and having added some dpf cleaner to the fuel there might have been sufficient extra soot going down the exhaust  to block the inlet pipe to the differential pressure sensor.

The pressure sensor error code has only come up since the egr was cleaned.  2 or 3 previous code readings didn't mention it at all.  It seems a bit of a coincidence for the sensor to fail at the same time.

Do you know how best to unblock the the pipes?  This ought to be a relatively inexpensive way to improve the diagnosis about a failed (very expensive) differential pressure sensor.

[iwonder]

The easiest way to check it's work properly is to check live data of the sensor on a scan tool at ignition on, idle and revved. That should give clear direction of where to go next. If you can't do that then as you said check the vacuum pipes would be best bet. And recheck all egr work done. 

When egr was cleaned was anything else done? Like manifold clean where egr sits?

[Lexuspete2]

Thanks again

I only paid for the EGR to be cleaned.  I'm pretty convinced they would have done this thoroughly but probably not anything more without telling me.

You state the vacuum pipes should be checked.  Being a novice at this on a steep learning curve my understanding until then was that the dpf inlet side was at some reasonable pressure not under vacuum.

Can blockages in the pipes be cleaned in situ including right to the feed from the dpf?

[Shahpor]

Code P1426 refers to a differential pressure sensor error.

This is what the manual says:

[Lexuspete2]

Thanks, very helpful

After discovering that the price of a new pressure sensor is £560 (really!) my brain was on overtime and I had already reasoned out that a blocked pipe between the dpf and sensor would give a similar effect to a faulty sensor. 

I've just got back from my local garage who were good enough to blow out the pipes whilst I waited.  I've just driven for about 15 minutes without the dreaded VSC light coming on - the longest time for several weeks.

I shall be taking it out on a rather longer errand shortly and hopefully problem solved.

Thanks to all who volunteered a contribution

[Osama babaldin]

I have Lexus 220d and 1428 come in I would to know what this code for.

Edited September 28, 2020 by Osama babaldin

[Osama babaldin]

Sorry the code is 1428 

[Osama babaldin]

Just now, Osama babaldin said:

 

[Rustams]

Hi. I have same code 1426

Could anyone text where is located

On Lexus is 220d tank ventilation valve?