P0700 on 2002 Accord but transmission working OK

[Mark Babunovic]

My 2002 4-cyl Accord with 175k miles has had P0700 and P1738 set for several months. I’ve ignored them since the transmission has been fine overall, and if it ain’t broke… The only thing out of the ordinary has been just a couple times (also over the last few months) that it has stayed in 1st gear too long. Each time I went super-easy on acceleration afterward and it went away. Most of my driving is short trips – 2-4 miles.

Last night I researched the codes again on ETCG and google. I found a youtube on replacing the 2nd clutch pressure switch to address the P1738. Should I do that and/or anything more? I’ve changed trans fluid regularly — no more than 15k miles since last change. Nothing else has ever been done w/ transmission. Thanks for any guidance.

Topic

[Daniel]

The “if it aint broke” scenario doesn’t apply here. The reason these trouble codes come up is to prevent a catastrophic failure. Before you replace any parts, keep in mind the OBD system sees the sensors via wiring and other components. So if the OBD system says that component is bad it’s really just having difficulty communicating with that component correctly or it is receiving unexpected information from that component. In other words; you need to check the component and wiring before blindly replacing parts.

[Mike]

Failure of those pressure switches is a known issue, and the local Honda dealers stocked them when I needed one for my 99 Accord trans. Definitely is worth replacing it.

[Mark Babunovic]

Thanks for the replies. While I’m definitely in the “don’t blindly replace parts” camp, it sounds to me from the pattern failure with those pressure switches, along with what looks like a 2 minute job to put in a new one, that there’s only upside to replacing it. If a new switch doesn’t take care of the P1738, I can regroup.

Any thoughts on the P0700, which from the ETCG threads can indicate slippage/a clutch going bad? Again, I’ve had zero drivetrain problems. Is there any other DIY diagnostic? If not is it worth paying a mechanic to take a look (and what could he/she do anyway, apart from recommending replacing the transmission when it turns into a problem)? Or should I just keep an eye on it, go easy on the car and let nature take its course?

[Mike]

The P0700 is just there to tell you that the engine computer has been notified by the transmission computer that there is a trans issue detected. It is sometimes set without another code present, but normally it sets along with a real code (your P1738). The idea of diagnosing the wiring for something like this is justified, but in this case of a pattern failure, I’d just replace the part.

[EricTheCarGuy]

+1 the P0700 just says a fault has been detected with the transmission, it’s not specific. Pressure switches are a known problem and not that expensive or difficult to replace. I’d recommend starting there as suggested. As for fluid changes, I hope you’re using Honda fluid. If not, I would recommend that you do. Also, 15K intervals is a bit excessive. Those transmissions were not known for problems. You’d be fine with 30K intervals for the fluid change. More info here.

http://www.ericthecarguy.com/faq/solving-transmission-problems

Good luck and keep us posted

[Mark Babunovic]

Thanks all – I’ll let you know. (ETCG has kept me on the straight and narrow — I use only Honda fluid for trans and power steering — and the 15k is just since lasts change, which I’ve done every 40k or so.)

[Mark Babunovic]

I got lucky and learned a lesson — check connectors first. I went to the Honda dealership to price the 2nd clutch pressure switch: $96. Thought I might be able to do better online, so took the part number and ordered it from autofairhondaparts.com for $52 all-in. They sent me the wrong part, which was clear after I took the connector off and saw that the new switch was a single prong vs. dual prong on the old one. So I put the connector back and …you know where this is going… the maintenance light went off. And because Autofair could not find the switch I ordered (the one they sent me was for 2003-on Accords, not my 2002), I was able to return the wrong part for credit.

While on the subject, any recommendations for online Honda OEM sites? (Autofair was fair about taking back the wrong part after I sent them a picture of the different connector.)

Thanks again for everyone’s help.

[Author]

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