StuB

Hey folks,

I've got a '99 Honda Civic LX. Recently the check engine light came on after some noticeable issues (mostly late shifting or erratic jolts), so I headed on over to Autozone to have it read out. The error is P0122 aka "Throttle/Pedal position sensor 'a' electrical circuit input signal had low voltage for a predetermined period of time'.

My guess is that the sensor itself has issues, and from some youtube videos and a maintenance manual, it seems that the sensor should be replaceable.

That said, I'm not a mechanic. I know electronics to a 'T' and could easily calibrate the TPS once installed, but between not having the right mechanical tools and this not being the kind of thing I'd want to break my teeth on, so I figured I'd take it to a mechanic.

They took a look while I was in a waiting room, and when they came back they said that the TPS was not replaceable; that the entire throttle body would have to be replaced.
I'm not generally prone to conjecture, but given the earlier findings, I suspect they just didn't want to deal with the break-away bolts and/or were hoping to upsell (though when asked how much the entire body would cost, they couldn't get a price).

That said, my engine bay does look different from those in the videos (where the TPS was easily accessed between the throttle body and the body of the car), so - being not-a-mechanic - I can't say with any certainty whether they were full of it.

Can anyone confirm that the TPS should be replaceable (even if it requires creative removal of the break-away bolts)? If it is, just how hard is it to get to the thing in this model anyway?

Not sure how this forum handles images (some end up inserting them at huge size), so I'll just link to an imgur album with shots of the engine bay instead. Yes, it's dirty. Yes, I just might give that a good cleaning if I do end up diving in, or have a local detailer give the whole car a once over for that matter.

http://imgur.com/a/Sh1Gn

Thanks in advance for any info you can share.

ezone

Honda does not sell the TPS by itself, they make you purchase a complete throttle body to get it.
US price ....sit down....about 800 beans (MSRP) IF it's even available. (note, they are not all the same, trans type makes a difference)

I'm sure you can do some searching on the internet and come up with a replacement sensor by itself for a more reasonable cost. No, I don't have a link but I've searched for the same in the past and found some

Removing the breakaways, use a punch or small chisel and hammer, force them to unscrew.

Setting up a new TPS, the output (return) voltage needs to be 0.49v at closed throttle. This value is extremely consistent across the entire car line, very little variation.

StuB

Yeah, the second person they called to inquire about pricing (as they couldn't find it in their system) did make them ask if it was an automatic (it is).

All sorts of websites seem to claim compatibility for make/model/etc. though the devil may be in the details (if anyone does know of any reason this would be a highly specific part, rather than generic-parts-seller 'matches your car' results, would be good to know)

However, as you said - and I somewhat felt like was the real issue at hand - it seems like the sensor is definitely replaceable (i.e. the sensor body isn't part of the throttle body as a single part), just that the mechanic doesn't want to deal with the break-away bolts.

I read about the voltages (finding a middle ground between closed @ ~0.5V and open @ ~4.5V for a 5V supply, scale as necessary) and that's thankfully something I actually could do... if I could just get to it; seems like taking the throttle body out entirely would be my best bet just to get a good angle on it.

I'll have to try a few other mechanics, see if there's one that does more than just unbolt and re-bolt and charge a premium for it.

ezone

No, the screws are easy to deal with if you already know what they are.

The mechanic/shop probably does not want to deal with an unknown quality part and the hassle of searching for it in unusual places (internet buying is not the way most shops operate) and hoping the part is right and works right once it gets there....and no way to guarantee it if it fails. Are you going to pay the normal shop labor rate for all this extra time it takes to hunt down the little part you need, and all the rest of the extra work it takes to save a buck?

At our shop, we do not do that either. You would be given an estimate for the throttle body replacement.


You simply adjust the sensor so the correct voltage (0.49v is preferred) is output with the throttle blade in the closed position (at rest), and lock it down. The rest of the sensor range will then be correct if the sensor is good.

Remove the throttle body, do the work on a bench or in a vise.

oneheadlight

StuB- I had to jump in here even though I don't post a lot on this forum. The TPS *IS* replaceable, and a quick look at rockauto shows Dorman and Standard Motor Products make replacement kits.

You were saying you know electronics to a T, and you know they're breakaway bolts, why not just drill them out, use the instructions in one of these kits (personally I like Standard Motor Products parts), and then calibrate it yourself? Instead of some shop that is too scared to try it based on some fear about not getting it right. Ridiculous. Maybe their technicians need to learn how to FIX a car, instead of throwing parts at it. I give up on technicians who just want to replace parts instead of fixing things, especially this when aftermarket kits ARE available, and wasn't difficult to find.

Plus if you do it, you know you'd calibrate it correctly.

Want to know how reasonably priced the kits are? try $23.79 and $25.79! A lot better than $800+ isn't it!?

here's the link to rockauto I found. You can probably find these parts elsewhere too.

http://www.rockauto.com/en/moreinfo....563&cc=1355611
http://www.rockauto.com/en/moreinfo....382&cc=1355611

http://www.rockauto.com/en/catalog/h...%28tps%29,5136


hope that helps!

ezone

That's why I told OP to do some looking for himself.
This morning I looked at local parts store website and found a kit.


Have an early Element in the shop right now....someone or a shop replaced the TPS and it isn't adjusted correctly (0.12v @ctp)....this thing stalls randomly and surges sometimes at part throttle.

I assume you've replaced a TPS yourself? In the kit, do the instructions ever tell you exactly how to calibrate the new sensor, and what the spec is?

old97civic

The aftermarket sensor has slotted holes so you can wiggle the TPS back and forth a bit until you get the right readings.

sdaidoji

iTrader: (1)

case closed, copied from another new thread.