Engine Management Light

[MLW]

LS 430. (64K miles)

After 3 years of faultless running, (35K miles), a problem.

Stuck in a 2 hour traffic jam when a motorway was shut. Stop-start for ages. Then the orange engine management sign light up. Will not go out when the engine is switched off. Car running absolutely normal. Have done 200 miles since.

Any ideas? Gummed up throttle body???

[Stupot]

As it could be so many possibilities, I'd either purchase my own code reader or try and find a local indy garage or mobile auto electrician etc who will read the fault code for you... I know it'll cost a few quid, but it will give you a starting point, otherwise you are just shooting in the dark. They might clear the codes and light and job done if all is currently well.

[Texas]

Just for your information the Engine Management System on a Ford vehicle will extinguish the dash EML after 15-20 drive cycles ( journeys) if the fault(s) that triggered the light in the first place no longer exsist. Invariably it is a sensor that has gone out of perimeters and no actual real fault is present with the car in itself and it will drive as normal.

I do not know if Lexus adopt the same logic ( no reason why not ) and you may find it goes out some time soon,but of course the info will be held in the ECU memory waiting to be read if it does.

Hopefully you haven't got an MOT soon!

paul m.

[cruisermark]

On the LS430this could one of many things including:

1. Oxygen sensor
2. leak in exhaust
3. dirty maf sensor
4. loose or faulty petrol cap

best thing to do is get it code read.

Once code read clear the codes and drive it  - if the fault come back then investigate and fix as necessary.

Hope this helps

 

[MLW]

I have a code reader. Where do I plug it in. Have done another 200 miles and it is perfectly normal and on a motorway is returning 32 mpg.

[BachelorDays]

You'll find the connector lower down the dash under the steering wheel. Do make a note of the codes before clearing them. 

Always worth checking the petrol filler cap as well. A loose cap/ dried rubber o-ring inside it can cause issues as well. Undo and reinstall the cap tightly and see if that in itself clears the light.

[MLW]

UPDATE

It was code P0155. This is heated oxygen sensor (HO2S) 1, bank 2, heater control circuit malfunction. I assume it is the oxygen sensor on the drivers bank of cylinders at the engine end, near the exhaust manifold.

Is it easy to replace?

How much?

I cleared the code, and also checked the petrol cap. It seemed ok, but I cleaned it and put a smear of Vaseline on the rubber seal and metal pipe to make sure it was air tight.

As I had bought some MAF cleaner, I have also given this a clean.

Some suggest it may be a faulty fuse. To be checked. Their are no systems such as rough running or starting. It is also returning 32 mpg on a long run.

[Stupot]

Has the EML gone off? If it has and the car is running fine, I'd just wait and see if it comes back before proceeding down any expensive avenues. 

[MLW]

Update.

Put it all back together and all was well for 5/6 miles on a test run, then it came back on again. It is running beautifully. I need the car for 450 miles at the weekend. Not sure what to do.

Any good independent Lexus specialists in Suffolk/Cambridge anyone would recommend?

 

[MLW]

UPDATE.

Took it in to my local garage and they replaced the lamda sensor at the front of bank 2.

The OEM part was £96.70p Labour 1 1/2 hours at £66 an hour. All in with VAT £234.84p.

Not too bad. They seem to have done a good job, including a 10 mile test drive and the light is now off.

As a matter of interest Lexus Cambridge wanted £203 for the part alone!

[The-Acre]

1 hour ago, MLW said:

UPDATE.

Took it in to my local garage and they replaced the lamda sensor at the front of bank 2.

The OEM part was £96.70p Labour 1 1/2 hours at £66 an hour. All in with VAT £234.84p.

Not too bad. They seem to have done a good job, including a 10 mile test drive and the light is now off.

As a matter of interest Lexus Cambridge wanted £203 for the part alone!

Yes, they wanted similar for my GS sensor but the same Denso part was much less from ECP.