Help with Code 10 (IAT) in H22/Accord
07-09-2003, 01:52 PM
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Help with Code 10 (IAT) in H22/Accord
Hey everyone,
New to this board (not new to the scene), and I'm hoping that someone here can help me out with my problem.
I swapped an H22 into my 95 Accord about 18 months ago. For the most part, everything has been fine, and I couldn't be happier with the swap. However, there's been one thing that's been popping up.
For quite some time now, my ECU likes to throw code 10 (Intake Air Temp sensor) after the car is warm and when the weather is warmer out (usually above 60 degrees). Let me run down the items and symptoms:
- As I said, it will only happen when the car has been running for awhile and when it's hot outside. EXCEPTION: On extremely hot days (like today), it'll throw the code as soon as I start the car.
- When it comes on while driving, I can feel the ECU retard the timing and cut my power.
- I'm not running hot, and all things in my car are carefully maintained (full oil, full coolant, well-running plugs, distro, timing, etc).
- I've replaced the IAT sensor with a new one, and that's not the problem.
- When I swapped my H22, I had a problem making the fans work, so I jumpered the fan switch to make the fans be on all the time (yeah, ghetto, I know).
OK, so my thoughts are these. I could try getting a cold air intake (currently running a filter on a stick), but I don't think that's the problem, since, as I said, the code will come on as soon as I start the car on REALLY hot days. The reason for that, I think, is the black hood I have is heating up the air under the hood, and causing SOME sensor to get extremely hot.
My question is: Could having the fans jumpered have something to do with the code? In other words, would the ECU be freaking out about a sensor getting hot WITH the fans being on, and throwing the code? I don't think this is the case though, since the ECT switches don't appear to run to the ECU according to my Helm's manual.
I've also thought that maybe it's that the sensor isn't "on all the time", and that the ECU only looks for a reading based on certain other readings from the engine (temps, etc).
I've done almost all the troubleshooting in my Helm's manual, without any luck.
I've got a few more items to check before I send the car to the wrecker. One of these involves getting a pinout for a JDM P13, since I think the JDM and USDM ECU's are different. My reason for this is, my Helm's shows there being TWO Engine Coolant Temperature switches, and my engine came with one. Can anyone help me out with that as well?
I know this is alot of stuff. Any help would be appreciated.
New to this board (not new to the scene), and I'm hoping that someone here can help me out with my problem.
I swapped an H22 into my 95 Accord about 18 months ago. For the most part, everything has been fine, and I couldn't be happier with the swap. However, there's been one thing that's been popping up.
For quite some time now, my ECU likes to throw code 10 (Intake Air Temp sensor) after the car is warm and when the weather is warmer out (usually above 60 degrees). Let me run down the items and symptoms:
- As I said, it will only happen when the car has been running for awhile and when it's hot outside. EXCEPTION: On extremely hot days (like today), it'll throw the code as soon as I start the car.
- When it comes on while driving, I can feel the ECU retard the timing and cut my power.
- I'm not running hot, and all things in my car are carefully maintained (full oil, full coolant, well-running plugs, distro, timing, etc).
- I've replaced the IAT sensor with a new one, and that's not the problem.
- When I swapped my H22, I had a problem making the fans work, so I jumpered the fan switch to make the fans be on all the time (yeah, ghetto, I know).
OK, so my thoughts are these. I could try getting a cold air intake (currently running a filter on a stick), but I don't think that's the problem, since, as I said, the code will come on as soon as I start the car on REALLY hot days. The reason for that, I think, is the black hood I have is heating up the air under the hood, and causing SOME sensor to get extremely hot.
My question is: Could having the fans jumpered have something to do with the code? In other words, would the ECU be freaking out about a sensor getting hot WITH the fans being on, and throwing the code? I don't think this is the case though, since the ECT switches don't appear to run to the ECU according to my Helm's manual.
I've also thought that maybe it's that the sensor isn't "on all the time", and that the ECU only looks for a reading based on certain other readings from the engine (temps, etc).
I've done almost all the troubleshooting in my Helm's manual, without any luck.
I've got a few more items to check before I send the car to the wrecker. One of these involves getting a pinout for a JDM P13, since I think the JDM and USDM ECU's are different. My reason for this is, my Helm's shows there being TWO Engine Coolant Temperature switches, and my engine came with one. Can anyone help me out with that as well?
I know this is alot of stuff. Any help would be appreciated.
07-13-2003, 10:22 AM
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Hey, I just looked in my service manual for a 94 Prelude, and besides changing out the sensor, it gave no help. I'd try checking really close for a vacuum leak. It took me 3 months to find one, kept throwing a code 43 (fuel supply system), but the vacuum line going into the map sensor had a small crack in it. If your car smokes a little white smoke and idles a little shaky, that could be it.
07-13-2003, 10:26 AM
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Nah, there isn't a vacuum line that goes to the IAT, nor anything related to it. All my vacuum lines are run correctly from and to the manifold. Nor does my car smoke or idle shaky. I really think it's a wiring problem, I'm checking into it today.
07-15-2003, 07:47 AM
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jdm and usdm ecus have teh exact same pinouts
so do civic and integra and 4th gen accord ecus....5th gen accords have one pin swap.
and the 2 coolant temp sensors...one is a sensor and one is a fan switch. JDM preludes done have 2. they only have one.
anyway it sounds like bad wires or jsut a plain old bad sensor.
usually when there is failure or intermittent failure it is best just replacing it.
jsut grab one off of pretty much ANY honda engine and try it.
so do civic and integra and 4th gen accord ecus....5th gen accords have one pin swap.
and the 2 coolant temp sensors...one is a sensor and one is a fan switch. JDM preludes done have 2. they only have one.
anyway it sounds like bad wires or jsut a plain old bad sensor.
usually when there is failure or intermittent failure it is best just replacing it.
jsut grab one off of pretty much ANY honda engine and try it.
07-15-2003, 11:15 AM
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Yeah, I replaced the IAT, but it didn't help. I'm thinking that there's either a problem with the ground, or that when we lengthened the wires for the IAT, something came unhooked.
As for the fans, my guesses are that it's either a bad relay or a bad fan switch. Both of those are on tap to get fixed as well.
Thanks for all the suggestions.
As for the fans, my guesses are that it's either a bad relay or a bad fan switch. Both of those are on tap to get fixed as well.
Thanks for all the suggestions.
07-19-2003, 05:15 AM
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IAT only monitors the temps inside the intake plenum to help prevent detonation from less dense air.
your ghetto fan switch rig and underhood temps wont affect this in any way. the MIL is indicating a failure of the IAT system, not that your car is actually sucking up hot air. if you were simply sucking up hot air, you wouldnt get a MIL... your car would just simply run less efficently to compensate for hot intake air.
the problem is the sensor or associated wiring... nothing else.
your ghetto fan switch rig and underhood temps wont affect this in any way. the MIL is indicating a failure of the IAT system, not that your car is actually sucking up hot air. if you were simply sucking up hot air, you wouldnt get a MIL... your car would just simply run less efficently to compensate for hot intake air.
the problem is the sensor or associated wiring... nothing else.
07-19-2003, 08:33 AM
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Exactly what I was thinking. I've noticed we strecthed the wires a little taut when we did the required lengthening for the swap. This can only mean that we broke something withing the wiring system.