Check [engine](/topics-engine-chevy/) light keeps coming ...

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Sure thing thank you

Please confirm the exact codes that you have received. Fan operation after the engine is shut off is possible, that is part of the vehicle design and is not a defect. It should be able to run for up to 10 minutes based upon engine temperature to reduce system pressure.

Understood but the engine is cold It has been sitting all day at least 8 to 10 hours and I had it on for literally 30 seconds to a minute

Okay, what type of diagnostic equipment do you have? You can confirm this by checking the live data to verify the fan is being commanded on. How long after the car is shut off does the fan turn off?

PP0340, P0365, P0335I don't have any diagnostic equipmentI am 2 hours from home on an army base that is closed for the weekendA few minutesAre you still there?

Yes I'm here. When you send me information I'm pulling schematics and diagnostics processes. This takes time. Please remember even if I don't respond I'm looking into your issue to get you the correct answer.

Perfect just checking No problem

Is the engine 1.4L turbo or 1.8L?

I understand, I've had a lot of cooling issues and I'm wondering if it's a temperature sensor malfunction1.4 l turboI'm trying to get in a bike ride before the sun sets, I only have about 20 more minutes so I'll try to respond as best I canBut take your time because I will be riding a bike :)

The P0340 and P0365 are both circuit codes for intake and [exhaust](/topics-exhaust-chevy/) cam circuits. While the sensor could cause this, these are not sensor performance codes. We most likely have one of the following issues: 1. Short to ground on the signal circuit 2. Open/High resistance on the 5v ref, signal or low ref circuits 3. Short to voltage on the signal or low ref circuits As you know the P335 is the same code on the crank position circuit. Similar potential issues. 1. Short to ground on the 5v ref or signal circuits 2. Open/high resistance on the 5v ref, signal or low ref circuits 3. Short to voltage on the signal circuit **Most likely the technician saw that the codes were related to the cam and crank sensor and did not further than that. These codes require you to test the individual circuits. Unfortunately you will need equipment to diagnose any of these as we need at minimum a multimeter to begin circuit testing. I've attached everything that you will need to test, but you cannot diagnose these without equipment as you will be testing wires between the ECM and each sensor. However these issues can also be caused by a failing ECM, incorrect engine timing and internal engine damage. It's difficult to say until you follow each step of the diagnostic process I've provided for these codes. They could all be related or they could be 3 separate issues.** . I’m glad that I was able to answer your question today. My goal is to ensure you receive a 5 STAR experience. Once you’re satisfied with my answer please take the time to rate me 5 stars at the top of your computer screen or by following the link on your phone. These ratings are extremely important to us experts. Tips are never expected by greatly appreciated as they make up a large part of our income. If you have further questions, please request me by using the following link and entering your question into the box. This ensures your questions comes directly to me: [https://www.justanswer.com/car/expert-yourautoinspector/](//www.justanswer.com/car/expert-yourautoinspector/) Thanks again for using Just Answer!!

Well that explains why changing the sensors didn't fix anythingHopefully not engine damage, I've tried my best to keep everything to specs when it comes to maintenanceThank you very much for all of this, I will ask the mechanic if he can do this. Thank you! Do you think the fan is related?

I don't believe the fan is related. In fact, I don't believe the fan is an issue at all. If the cooling fan is switching off and on as needed when the engine is on I would not be concerned unless it remains on for more than 10 minutes. I am a bit concerned that it comes on even when the engine is cold, but difficult to say what is causing it.

That's fair, I wonder if it could be a faulty temperature sensor? Thank you for answering You've been extremely helpful. I will say I used to get check engine lights that came on and it indicated mass air flow sensor problems, I've never seen that code again after I started using higher octane gas, however I have been putting cleaner in with the gas I'm using in the hopes that that would help, I don't think it's made a differenceDo you think going back to mid-grade gasoline would help in the meantime? Until I can get back to a mechanic?

It could be a faulty temp sensor, but if that was the case the fan would be on when the engine is running. The sensor sends the signal to the engine computer which then commands the fan. If the vehicle thinks the coolant temperature is hot then it turns the fan on. If this was the case I would expect the fan to turn on while the engine is running and remain on when it's shut off. Gasoline should not impact these issues as they are mechanical issues with engine timing or electrical signal issues in the wiring. Fuel choice will not make a difference in this case.

Excellent, thank you

You’re very welcome

took it to the dealership, they THINK it's the ECM

Makes sense.

Well shoot I'm glad to have an answer but do you think that is something to do with a manufacturer's defect or is it just wear and tear you think?

It's very difficult to say without having someone break down and inspect it. I would say after 8 years if it was a manufacturing defect it would have most likely had an issue before this point. Parts failure is the reality of vehicles unfortunately.