Resetting ECU CEL Car Dies at Idle Now

[sethster]

Hello everyone, 2003 Solara 2.4 liter auto with 100,000 miles here. I just recently threw a CEL with a code of P0171. I checked for some leaking or bad air hoses, and found one that wasnt on completely right after the MAF Sensor. I reset the code by taking the positive battery terminal off for 30 minutes to try and see if the car will still throw another CEL, and now my car dies at idle.

You can start it, rev it up, drive it, whatever but as soon as you depress the brake and come to a stop, the car drops below 350 rpms and dies. If you start the car and dont depress the gas, the RPM's drop and the car dies too. I have reset the ECU before the same way, and the car usually will do the same thing and idle really roughly for about 5-10 minutes, but then it returns back to normal. It has been two days of driving now and it is still doing the same thing, and it seems worse.

There is no CEL on, the car seems to run perfect and get good gas mileage, but now it just idles so low that it wont continue to run.

Does anyone have any idea on what might be causing my problem? Is there a way to adjust the Idle manually on the 2az-fe engine?
Any help is greatly appreciated...

[Akfahad]

Have you checked the IAC (Idle air control valve)? My car did that once, use to die almost every time I came to a stop and if it didn't, the idle was not pretty. Have your mechanic check it out, maybe time to be replaced, especially with about 100k miles. that's about the same time mine went.

[gnegroni]

Using the search function I found that P0171 is a lean condition on bank one (not sure which bank is 1). I don't think there are screw-like idle adjusts on our 2AZ-FEs but I could be wrong.

The manual has the following possible trouble areas (take a deep breath):

P0171 System Too Lean (Bank 1)
1. Air induction system
2. Injector blockage
3. Mass air flow meter
4. Engine coolant temperature sensor
5. Fuel pressure
6. Gas leakage in exhaust system
7. Open or short in A/F sensor circuit
8. A/F sensor
9. A/F sensor heater
10. EFI relay
11. A/F sensor heater and EFI relay circuit
12. PCV hose connection
13. PCV hose
Come on DTC Stored ES-121

This is the link for the manuals if you want further reading, but its for Gen2 (since we have 2AZ-FE too, its not bad reading):

http://cns-design.ru/files/solara/pdf/

Hope this helps, and good luck!

[sethster]

Using the search function I found that P0171 is a lean condition on bank one (not sure which bank is 1). I don't think there are screw-like idle adjusts on our 2AZ-FEs but I could be wrong.

The manual has the following possible trouble areas (take a deep breath):

P0171 System Too Lean (Bank 1)
1. Air induction system
2. Injector blockage
3. Mass air flow meter
4. Engine coolant temperature sensor
5. Fuel pressure
6. Gas leakage in exhaust system
7. Open or short in A/F sensor circuit
8. A/F sensor
9. A/F sensor heater
10. EFI relay
11. A/F sensor heater and EFI relay circuit
12. PCV hose connection
13. PCV hose
Come on DTC Stored ES-121

This is the link for the manuals if you want further reading, but its for Gen2 (since we have 2AZ-FE too, its not bad reading):

http://cns-design.ru/files/solara/pdf/

Hope this helps, and good luck!

Thanks for the reply... I am not really asking what the problem was for the CEL. I know what the code was, it was telling me that the engine was running lean at the air/fuel sensor, so that could be any of the above problems like you said (kind of a PITA if you ask me, I wish it could be more specific).

I am interested to know why my car will not idle anymore. Even with the CEL on it would run fine, and now that I reset the computer it does not throw any codes, yet it will not idle. It was like instantly the car just started doing this, it didnt progressively get worse, it was immediately after I unplugged the battery and reset the ecu...

[kingkakyle]

you can try unplugging the battery again to reset it
and then turn the car on and let it idle for about 5-10 minutes then drive a few miles
i did that when i installed my muffler....it idles really horribly...although it never died it was rough...like there was a 10 earthquake

[sethster]

you can try unplugging the battery again to reset it
and then turn the car on and let it idle for about 5-10 minutes then drive a few miles
i did that when i installed my muffler....it idles really horribly...although it never died it was rough...like there was a 10 earthquake

Yeah, thats what my car usually does when I reset the ecu. But for some reason something is way off...

I decided to clean my Throttle Body/IAC just for the heck of it, and the problem seems to have disappeared. There was so much crap on my throttle body that you could write your first and last name on the concrete with the amount that came off with one fingers wipe.

I will let you all know if the problem comes back tomorrow, hopefully it doesnt. I guess it was either the throttle body/IAC was too dirty, or a sensor connector wasnt on right and I bumped it while working on the throttle body. Either way it works now so its all good.

Thanks again