Lexus Troubleshooting Questions? Ask a Lexus Expert
Do you have the code numbers that would be set in the computer causing the check engine light to come on?
In order to get the codes from the computer you need a code reader and plug into the OBD port under the instrument panel. I'm not sure what country herein or whether you have access to or can purchase a generic code reader but you can get one for about US$60 these days. By plugging into the port you can retrieve the malfunction codes from the engine control computer. Here in the USA most auto parts do it is a free courtesy. With these code numbers I can give you a better idea of what's going on. Is this something you be able to do?
the OBD connector is under the instrument panel the instrument panel is the dashboard the connector is on the driver side up underneath you'll see the connector it should match the connector on the scan tool/code reader.
There are way to many to list out. Did you get the code numbers and I can look it up.
What model Lexus do you have and is it loosing power or performance?
I cannot definitively Tell you whether the engine is failing with what little information I have. If you are losing power that does not necessarily mean that the engine is failing, it could be something in the injection pump or fuel pressure related to it. There could be a safety system set up causing it to lose power depending what the malfunction code is causing the check engine light to come on. As a general rule Toyota engines are very reliable and unless you've got excessive amount of miles I would have to think that it's probably more Engine control related Type of failure.
I would have to say that that is probably not normal but the car is going on nine years old it may be more due to the age then the mileage. That would affect the coolant pump and the seals there. I am more surprised that there is a malfunction EGR system given the mileage because typically it has to be higher mileage before the EGR valve systems start to mess up.
It never hurts to ask for assistance but is not likely given the age that Lexus will do anything about this. Filling the tank with petrol version diesel should have no effect on the water pump and is likely going to affect the EGR valve either. I would be more concerned about internal engine issues if it ran long on gasoline or a diluted mixture.