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Hello! I am noob so bare with me. I have an 05 Civic, EX SE 2 door. 1.7l, auto trans. It has 142000 miles on it. It has been an awesome car. The other night on my way home from work the dreaded check engine light came on. Seemed to be running fine so I continued the rest of the way home. I put it in park to opened the gate to my house. When I got back in and put it in drive it slammed into gear and surged forward. I put it in nuetral and back into drive and it did it again. I tried reverse and same thing. I put it in the garage and shut it off. I started it back up and it wouldnt do it. The next day I borrowed a friends code reader. This is what I came up with.

P0302-cyl 2 misfire
P0122-TPS
P0303-cyl 3 misfire
P0300-generic misfire
P0122-TPS

I cleared the codes and they havent come back yet, I have put about 40 miles on it since I cleared them.
My mechanic who changed my timing belt said if it had a misfire it *could* have affected the voltage to the tps throwing that code in there. For good measure I checked the coils and plugs last night. One of the coils, (cyl3) had a brownish tint to it like it was heat discolored. I checked the plugs and they look good(changed them a few months ago with NGK)
Sorry for the long winded post, but I know the more info when trouble shooting the better.
I dont want to just throw parts at it.
Anyone got any ideas where to go from here?
Thanks,
TJ

 
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So you have misfire codes and a TPS code.
Slamming into gear was likely because of an active TPS problem.

Got Freeze Frame data? That would be helpful.

I'm pretty sure it can't.


You cleared the codes so I'd say to wait until the CEL comes back on -- and check what the code is immediately, then decide what to do next.


Right now, I'd guess the TPS will be the problem for the TPS code.....Wiring problems normally cause very persistent codes.

There are many possible causes of misfires. ... When it sets a misfire code again, I want to see the freeze frame data -- before I blurt out some random answer..

 
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Thanks for the reply. There was freeze frame for one of the misfire codes, but I think after I erased the codes all that info on the scanner went away.
This may be premature, but I thought I saw somewhere on here that throttle bodys for 7th gens were only about $100, but that must not have been OEM. The closest honda dealer to me quoted me $360 today. I have read enough to know these cars are very picky when it comes to aftermarket vs. OE. Are there any aftermarket throttle bodys that are worth it? Not going to buy one yet, just trying to get the funds lined out if it comes back as the TPS.

 
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Right. It's gone now. Gotta wait until it resets a code.

I'm impressed you found it though.

Majestic Honda shows it for $253 plus shipping.

http://www.hondaautomotiveparts.com/...=THROTTLE+BODY


Yes, unless the aftermarket part is really an original part that has been reboxed.
It happens often, and 99% of the time, nobody in the parts store knows there is any difference.


I didn't even know aftermarket had throttle bodies available.
I DO know someone in the aftermarket sells the TPS by itself, but a good number of people out there shouldn't even attempt to replace it. But it is possible.

 
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Thanks again. On my way home today I was coasting down a hill doing about 40mph, and the car started to surge. And maybe surge is a strong word for what it was doing. It wasn't like a miss, it was like I was just barely putting my foot on the throttle so that the compression of the engine wasn't holding it back, and taking it off again. It did that about 4 or 5 times in about 2-3 seconds then stopped, but no check engine light. Grrr. I have a big trip coming up in a few weeks. I hope I can resolve this, I don't want to have issues on the road and don't want to have to take my taco, with the lift, tires and armor it isn't fuel mileage friendly.
Again, thanks for the help. I appreciate it.
TJ

 
Rep Power: 518

P0122: TPS voltage low

Here is what the computer had to see in order to set that code: The output voltage from the TP sensor is 0.23 V or less for at least 2 seconds.


You could monitor TPS voltage while driving if your code reader will support live engine data. It might be too slow to let you catch a glitch in the act though.

You could use a voltmeter to do the same thing, backprobed right at the sensor or at the PCM.
Do a really s-l-o-w sweep test of the TPS while watching the voltmeter (connected), see if the response is smooth and linear with no dropouts throughout the entire range of operation, both increase and decrease. Several times. (If it does anything wrong at all here, it's bad.)



You probably should monitor the 5V side of the TPS at the same time, make sure it isn't losing its power source elsewhere to cause the code.

Wiggle check the wiring. Drag test the female terminals, check for spring tension.


Condemn the TPS if nothing else obvious is found?

 
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Should there be a voltage range? Or just as long as it doesn't drop below 0.23V its ok?

Upon edit, the wife took the car to dinner with some friends. As she was pulling back in the garage the light came on. She said it didn't do anything funny like a misfire, just came on. So I'll read codes tomorrow.

 
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That .23 is a threshold point for the diagnostic monitoring by the PCM. It's a voltage that is beyond the normal lowest point of operation, but above the voltage produced by an open or short circuit.
A good TPS will never get near that .23v.


General spec is "about 0.5v when the throttle is fully closed and about 4.5v when the throttle is fully opened"...

What I see: TPS normal (voltage) range of operation when viewed on a scantool is (almost exactly) 0.49v at closed throttle, to somewhere around 4.50v at wide open throttle.


That 0.49v seems amazingly exact and very consistent when seen in the computer data list, 99% of the cars across Hondas entire fleet are set to this with almost zero variation that I have ever noticed (does not apply to throttle-by-wire). I might allow a +/- 0.05v, but it would seem very unusual to me.

 
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Scan shows the P0122 again, with no other codes.
Also, here is the freeze frame data.

Fuel sys 1 CL
Fuel sys 2 NA
Calc Load% 38.4
ECT-F* 178
STFT B1% 0.8
LTFT B1% 5.5
MAP in Hg 11.5
RPM 803
veh spd mph 2
spark adv * 0.0
IAT F* 39
TPS % 0.8

Looks like I will be ordering a throttle body. Sucks to have to drop the coin, but very glad it will be fixed.

 
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I think the TPS% should read somewhere around 9-10% when throttle is closed (I read the data in volts on my scanners).....

Looks like it was way below that when the code set.
Definitely a problem.


I guess all you can do is plan to deal with those if they come up later on.
Always!

 
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The throttle body showed up today, I am headed out to change it right now. Opinion on throttle relearn? I read up a bunch on it today and there are some mixed ideas. I would appreciate the input. Thanks.

 
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There is no throttle relearn.

There is an idle relearn, you probably need to do that.

Disconnect the battery while you work.
Reconnect it,, run the engine until it is warmed up. Driving is ok to get it warmed up.

Let it idle in park or neutral with no accessories or electrical loads.
Idle for 10 minutes.
If the radiator fan runs, add that time to your 10 minutes.


That's it.