ECU malfunction Codes at 159,000 miles / Service

Cleaning the throttle body is an easy DIY. The main issue is getting to it, removing the plastic plumbing over it. Long reach offset tip needle nose pliers are hand for reaching hose clamps. Just take your time. Look carefully, or even take a pic, of the hose going onto the throttle body. I know on ours it's orientation is not locked, ie: you can rotate it. So when putting it back on it can be a bit puzzling as to best orientation.

For cleaning, just spray carb cleaner onto a clean cloth and wipe out the carb barrel. A q-tip might work better near the pivot point of the blade. open the blade by pushing down on one side, then you can clean a bit beyond.

 

I have never done it and have 284k miles on my 2004 Prius.

JeffD

 

Debatable. It is pretty easy, an hour outa your life, at most.

 

Hi Folks, I hope you'll allow me to extend this useful thread, rather than start a new one. I have a Gen 2 Prius with 170K on it, purchased 9 months ago at 166K. I had a catalytic converter shield installed to prevent theft. I have got the P0456 code once before on it's own. I reset codes, cleaned gas cap gasket and prayed. Now, a couple of months after that P0456 code, I’m getting two codes P0456 (small leak) and P0137 (Bank 1, sensor 2 - downstream O2 sensor). It's been hot (for here) - in the mid 90s. I understand from this thread and the good links that the low voltage on Bank 1 sensor 2 indicates that the engine is running lean, too much air. I replaced the cap, just to be done with that question ($44 at my local Toyota st/dealership...) Do any of you have any immediate suggestions for these two errors together - such as leaks, vacuum hoses that fail, EGR/EVAP stuff that commonly goes wrong? I would prefer not to ask the shop to replace the O2 sensor, since it is now riveted in behind the catalytic converter theft shield. I hope the O2 sensor/wiring hasn' failed due to excessive heat build up, also...

Thx!

 

I don't know, this was such a goofball thread you might be better off starting a new one. It looks like the only thing you have in common with it is one P0456 code.

The P0456 shows that your fuel tank evaporative control system has got a leak in it somewhere, bigger than a 0.02 inch pinhole, but smaller than the threshold that would set a P0455 gross leak.

Your P0137 almost certainly doesn't indicate that your engine is running too lean. The reason is that the code is set during a test where the ECM deliberately fudges the mixture for 15 to 20 seconds to make the engine run too lean or too rich. If the ECM is deliberately injecting too much fuel and the sensor continues to say nothing but lean, you get this code, and there's a very good chance there is a sensor or wiring issue. P0171 would be a more common code to see if the issue was really the engine running lean.

The repair manual has a 13 page section on the P0137 with troubleshooting steps you can follow to pin down what's going on. Looks like the early ones can be done with Techstream and a meter without disturbing any rivets.

 

Thanks, I'll consider doing a new thread if I can't figure it out soon - I noticed the OP had an ABS error but had the same two also that I have. Silly question, but which repair manual should I buy or subscribe to, if a website? With some cars, I've bought Bentley, with some German cars it's been DVDs on ebay...

Thanks

 

To be serious about taking care of the car, there's only one; we've got this wiki page that Elektroingenieur kindly created explaining different ways of getting access to it.

 

Thanks - what of these have you purchased, or frequently paid for access to? Great Wiki page on manuals, by the way! I like the Bentley series, so I bought one of those to start with.

 

I live in the US, so techinfo.toyota.com is the site for TIS in my area. I typically just go straight there and pay the $20 for two days of access when I need it (was $15 years ago). When I first bought the car, I spent the $90 (but it was $75 then) for a month, so I wouldn't feel rushed. I've saved a bunch of stuff to refer to without always feeding the meter again. When I have questions that can wait, I tend to save them up, then I'll drop a $20 and get a bunch of answers (and you can usually tell when there's a two-day period that I post a bunch of unusually-complete answers to other people's questions on PriusChat).

Elektroingenieur described several of the services that might make actual TIS information available to you through, for example, subscription agreements with a local public library. So far my TIS habit is costing me less than $20 a year on average, so I haven't looked very actively into whether my libraries here have such arrangements.

It has been years since I formed the opinion that simplified third-party manuals weren't worth the effort of turning the pages. I wasted more time trying to guess at what they left out or explained wrong than I could save by using them. So for me it would be either TIS directly, or TIS through some other access provider.

Edit: as a corollary, generally when you see a post talk about "the repair manual", "the wiring diagram", and so on around here, it means the real ones on TIS. Likewise, if you post about something you read in some other manual, like a Bentley or whatever, you should identify what manual you mean. Otherwise, readers might be using 'the' manual trying to follow along in your reasoning, and spending time thinking "wait, where does it say, no that's not right ... huh?".

 

Great info, thanks. So above when you said that there were 13 pages in the manual about that Bank 1 sensor 2 error, that would be on the techinfo.toyota.com site? I will probably try it out with this issue in mind. And thanks for earlier suggesting that I can instruct my local well intentioned neanderthal shop to try things other than removing the cat theft shield first!

 

I think I meant that mostly as encouragement for you, if you had some interest in DIY diagnosis.

After the first few steps, you might quickly reach a point where the next step has your meter probes on the sensor connector, and maybe your local shop won't really be keen to start a diagnosis job and then, I don't know, phone you with the car on their lift to get your permission to proceed.