Engine Management Light

January 15, 2006

PLEASE PLEASE PLEASE DONT DO A THING TO YOU AVENSIS IF THE MANAGEMENT LIGHT IS ON UNTILL YOU HAVE HAD THE SYSTEM MAPPED ON A LAPTOP WITH OBD SOFTWARE AND INTERFACE.

You will not find the problem with the code only as you won't know what the system is doing to cause the fault.

It seems that lots of manufactures main agent are crap at finding problems with cars resulting in owners going down the new front o2 sensor, new rear o2 sensor then cat replacement route to still have the light on.

It's not just Toyota, even a BMW Main Agent in Germany couldn't solve a dirty Mass Air Flow meter, results in rich mixture, engine running in open loop, not managed by o2 sensors and in extream cases damaging the cat. You then replace the cat, however the system is still running rich and the light comes on again. You have wasted £400 plus for cat, £130 each o2 sensor (3 0n old 1800 vvt-i) plus labour and vat at Toyota agent.

This link http://www.gendan.co.uk/tool_chooser.php will get you to Gandan page for Toyota compliant obd-II interfaces who sell Scantool interface from £67, or ESP at http://www.espautomotive.com/trolleyed/index.htm which start from £100 up to £150 for the full version, which is fab for finding problems as you can moniter 4 sensors real time to see what is causing the problem.

Also they all give the fault code and will reset them when you have sorted out the problem.

Seems a lot to spend, but it is less than having 1 good working sensor replaced because you think its faulty.

It will show if cat is working, by monitering down stream o2 sensor which will not switch much if up stream sensors are ok. If up stream sensor is faulty, the down stream sensor will try to control the mixture to get the emissions correct, which it may not be able to do and will be an mot fail, so you replace a good cat.

It also seems that the narrow parameters on the 1800 vvt-i make matters worse as it senses out of range values sooner than other cars, putting the light on.

I have been researching this since b4 christmas and realise that modern cars cant be diagnosed with out this kind of software and interface, code readers will help and are half the price but you will be working in the dark.

The Avensis seems to suffer with these problems more, but is a very good car on the whole, it's the diognosing that is letting it down. I have an Avensis as a taxi in Southend with light on as many others have, there are many more now. One new shape has done 50,000 and is having a new cat under warranty which it may not need.

When I am confident with the software, I will try to resolve all their problems. If you are prepared to drive to Southend I will map you car for a small fee (£5-£10) and show you what your problem is caused by.