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Toyota Service
Toyota Service, Toyota Expert
Category: Toyota
Satisfied Customers: 4605
Experience:  30+ Yrs of auto experience, Award Winning Svc. Manager; Just Answer Customer's Choice Award Winner
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I have a 2001 lux turbo diesel. KZN 165 factory turbo. The

Customer Question

Hi Tom, I have a 2001 Hilux turbo diesel. KZN 165 factory turbo. The orange engine light comes on when driving on highway but goes out when around town. Could it be a fuel related problem?
Submitted: 1 year ago.
Category: Toyota
Customer: replied 1 year ago.
I have taken it to Totota and they said some code comes up for fuel filter. The filter has been replaced and the old one was a little dirty, but nothing at all extreme.
Expert:  Toyota Service replied 1 year ago.

Hello. Welcome to Just Answer. Please allow me to assist you. I would not think this a fuel related issue, as a fuel problem would cause the light to be on all of the time. The one major difference between city and highway driving could be a 'cooing system temperature too low" issue. A scan would tell us this if this is true (it would cause a P0125 code to be displayed on the scanner). In city driving, the coolant will not have a lower temperature because of stop-start driving and rarely getting up to highway speed. On the highway, the air rushing thru the radiator scan lower the coolant temperature.

Expert:  Toyota Service replied 1 year ago.

oh, Fuel filter codes? would you happen to have these codes? were they provided to you?

Expert:  Toyota Service replied 1 year ago.

I do not see how city driving keeps the light out and highway driving allows the light to come on, with regard to a fuel filter problem. It takes more fuel to get the vehicle form zero to 20 miles an hour than it does to maintain 50 miles per hour.

Expert:  Toyota Service replied 1 year ago.

Perhaps if you had the codes that were given to you we would be able to deduce the root cause. Until then, I am going to stick with my cooling system temperture too low theory. This would be easily rectified by replacement of the thermostat. This is a rather inexpensive repair.

Customer: replied 1 year ago.
Toyota did not supply me with the fuel codes, so I was unsure whether it was fuel to begin with. I have had a new radiator and coolant in the vehicle in the last couple months. I don't understand how cooling can cause an engine light to come on every so often. This engine light seems to come on every 12 months until the local mechanic somehow cleans the terminals. As long as I don't need a new injector pump.
Customer: replied 1 year ago.
Especially when the vehicle shows no signs of getting hot to begin with
Expert:  Toyota Service replied 1 year ago.

The engine needs to be at 192 degrees F to maintain proper operating conditions. Below this temperature, for a prolonged time, with air rushing thru the radiator, the coolant can drop to 150 degrees easily. In other words, the engine is not hot enough. We call this "closed loop operation" in the trade. This is where the oxygen sensors work properly and control certain actions. If the coolant is too low, the system reverts to "open loop operation", where the oxygen sensor input is ignored. SInce you did not mention that the vehicle runs differently, and it is not a temperature problem, you may have an emission related issue.

Expert:  Toyota Service replied 1 year ago.

In any case, I do not think you need an injector pump. If you did, it would certainly run bad.

Customer: replied 1 year ago.
Sorry I should have mentioned, when the orange engine light comes on, the vehicle loses all power and goes into like a limp mode, and the engine makes some strange sounds until the light goes out.
Expert:  Toyota Service replied 1 year ago.

Well that does make a huge difference then.

Expert:  Toyota Service replied 1 year ago.

If it is running poor when your light comes on, yes, it could indeed be an injection pump. That is very possible. What you really need tor do is get the actual fault codes. We could speculate on what it 'could' be, but, without the codes, we will not know what is actually causing the problem.

Customer: replied 1 year ago.
That's what I was hoping my local Toyota dealer would do which was get the fault codes to get a diagnosis. They seemed to think a new fuel filter would help solve the issue and didn't look further.
Expert:  Toyota Service replied 1 year ago.

I am at a loss with their thinking a fuel filter would cause a check engine light to come on and it run poor at highway speeds. Just does not make sense to me.

Customer: replied 1 year ago.
I don't think my local Toyota dealer was interested and put the issue in the too hard basket. I don't want to spend $2800 on a new injector pump and find it wasn't the pump at all. I'm finding it hard to get a diagnosis for this engine light issue. But I do appreciate your input.
Expert:  Toyota Service replied 1 year ago.

It is not hard to extract the codes from the computer. Perhaps visiting them again and specifically requesting codes, and the reasons for the codes would be in order here. Not parts replacements, but hard and fast diagnostics and potential causes and the eventual remedy.

Expert:  Toyota Service replied 1 year ago.

You are very welcome. If we had the codes we could narrow this issue down quite a bit.

Customer: replied 1 year ago.
I think i need to visit them again and get the codes off my local Toyota dealer. And have them say what the codes are to me so I can narrow this issue down a lot.
Expert:  Toyota Service replied 1 year ago.

indeed.

Expert:  Toyota Service replied 1 year ago.

Please get back to me when you get the codes if they are not very clear on the cause, or if you want a valid second opinion.

Thanks for choosing Just Answer. A positive rating for my input would be greatly appreciated. Thanks again

Customer: replied 1 year ago.
I took my Hilux to Toyota yesterday. It comes up with a code 4 and they said my fuel filter was dirty again and that my problem may be the TCV. But they said to get an accurate test to see if its working, the vehicle must be cold. They tested it and it seemed fine. But they said it could be sticking when reaching the 90kmh to 100kmh. I am getting closer to narrowing the issue down.I value your opinions and rate you very high for your help.
Expert:  Toyota Service replied 1 year ago.

You are very welcome.. Pls let me know the cold test results.

Customer: replied 1 year ago.
I will let you know for sure
Expert:  Toyota Service replied 1 year ago.

Thank you