QuestionQUESTION: Hi Randall,
I own a Sonata 2.7 V6 (2002). Recently I changed the plugs and the timing belt and since then the problem started. The engine starts but stalls for few minutes and then gets back to normal. This happens every time you start the car. On checking with the Scan tool, it shows error P1166. I have changed the HT cables to the plugs and tested the coils too. All Actuation tests with the scan tool shows normal operation and does complete successfully. I suppose the next step is to check or replace the Oxygen sensors. The error mentions about bank1. The dealer does not have much expertise. He has suggested a Oscilloscope test to verify the functioning of the Oxygen sensor. Please send me your suggestions and the steps to follow to eliminate this problem. I look forward for a detailed step by step approach from you..
ANSWER: Error code P1166 is a primary indicator that the ECU/ECM is receiving negative feedback from an O2 sensor (as you mentioned as your next step) or a bad O2 sensor control. Running a Oscilloscope is actually not a bad idea in this case, and if it proves to be an O2 sensor, it is most likely the one behind the catalyst control. The only other thing that comes to mind that may trigger a P1166 is a leaky air intake system, and that can be solved by doing a simple smoke test before you end up taking the vehicle to Hyundai. I would definitely recommend doing this first. If it turns out to be a leaking intake, then that will save you a lot of time and money. The reaction that your car is having at this time is typical for a faulty air system or O2 sensory as well.
If there is anything else I can help you with, just let me know and I will do my best to answer it for you.
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QUESTION: Thank you very much for the suggestions. Can you describe what is a smoke test and how do I execure the same?? Do I need any special equipments?? Is it an exhaust analyser?? And what are the indications of faulty/leaking intake..
ANSWER: A smoke test is going to basically run a smoke (typically thick enought to see well) through your intake system. If there is a leak in the system, then the smoke will begin to show where the intake is leaking. It is quite different than an exhaust analyzer where you would just measure a digital reading of the emissions. You can get the equipment to do it yourself, but I would just have someone else run it for you. Check with your local shops to see if there is one that will run a free smoke test for you. Try calling Autozone as well. I know that they do free engine analysis tests, but I am not sure if they do smoke tests or not.
As far as the indications for a faulty intake system goes, you will typically notice stalling as you said. You may notice the engine choking a bit when idling or a lack of acceleration occasionally compared to its norm. In my personal opinion, it is going to be a faulty O2 sensor. If the vehicle is starting but stalls for a bit then goes to normal, it sounds like the sensor it putting out a bad code when the car starts, and then the other sensors and regulators balance itself out and the vehicle starts running in a normal state.
Go ahead and have the Oscilloscope test ran, and if it is not a sensor, I would be quite surprised. See if you can find someone else to run the test besides the dealer, as we all know that they like to charge an extra large amount for anything that they do.
I hope that this solves your problem and would appreciate your feedback on what is happening with your vehicle. It is always nice to know what has happened in situations like this for my own personal reference as well. Best of luck to you and I will gladly help you out more if needed.
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QUESTION: The DTC mentions as p1166 - fuel trim(bank1). I feel as the error is referring to Bank1, very likely it could be O2 sensor failure. I suppose if there was a faulty intake, it would reflect on both banks. Please correct me if my assumptions are incorrect. Or is it likely that faulty intake is likely to report problem for Bank1 only? I can also hear a air suction sound near the throttle, it could be normal sound but currently any air intake sound abnormal. And secondly, though the RPM gets back to normal and the engine does not stall after a few seconds, the acceleration is poor. These are few more observations.. Please do let me know if any of these help locate the faulty component..
AnswerP1166 is a sensory issue with B1 (bank1), however, a faulty intake can trigger that code as well. It does not necessarily mean that it would trigger a P1167. It is odd for it to do so, and as I mentioned, I would personally believe it is a faulty O2 sensor near the catalyst control, as that would be referring to the bank1 section of the code.
A faulty sensor can cause a bad signal with your ECU/ECM therefore causing poor acceleration as well. Any mechanical or electrical part of your air intake and exhaust system will effect performance greatly if there is a malfunction.
Best guess of mine, check the B1 O2 sensor, as that is most likely the problem you are having. I am sure that you will get it worked out with ease. Best of luck, and I hope that this has been of assistance to you.
