2002 Prius sudden loss of power while driving followed by alert

The Classic accelerator pedal is a known problem area. That assembly contains two variable resistors which tend to get "noisy" after a while. This confuses the hybrid vehicle ECU and causes the hybrid vehicle warning icon to appear.

The fix is to replace the accelerator pedal. Bob Wilson also can make a repaired pedal available, upon request.

 

Called the "big hand" problem, there are several options:

• ~$500 - replacement from Toyota Service Center
• ~$150 - refurbished accelerator
  
• ~$65 - recent Ebay posting of an NHW11 accelerator
• follow Doug's refurbishment instructions

Bob Wilson

 

You'll need the codes to proceed further. Your symptoms can be caused by many issues, only one of which is a accelerator pedal issue. In particular, some fail-safe operations, which are triggered when certain codes are set, produce symptoms not unlike those you are experiencing. In other words, your vehicle's behavior could be produced by the problem itself, or by the vehicle's attempt to work around the problem.

If you want to throw an accelerator pedal at the problem in hopes that it will solve your issue, then there are plenty of folks who will help you with that. However, if you want to determine what the problem is with certainty, it will take a bit more work.

One last point: I wouldn't recommend "rebuilt" accelerator pedals. They are safety items just as much as brake parts are safety items. It's just not worth the risk to save a few dollars.

 

You might consider building a test jig:


Here are the test results before and after:


GOOD LUCK!
Bob Wilson

 

It is reasonable to be cautious of field-modified parts, especially if that caution is illuminated by an understanding of the rebuilding process. However, what we know so far is that a substantial proportion of the OEM units have failed. While still few in number, none of the modfied ones have have failed.

It would be interesting to know if (and how) Toyota manufactured them better, later in the model run. That could provide substance to a preference for the replacement at retail. But if such information is Company Proprietary then we will have to wait until somebody puts a newer pedal on a test jig.

 

Indeed. And folks who sell modified parts often fail to carry commercial liability insurance.

What is that proportion?

How do you know this?

Have you seen any Gen 1 Prius accelerator pedal assemblies, manufactured in the last five years, fail?

I don't see how a test jig would reveal anything other than correct voltage signals. That can be carried out without removing the assembly from the vehicle. Really, you'd have to disassemble the assembly and analyze both the design and the materials to confirm any design changes.

 

It is fairly straight forward. Key elements:

• test before repair - use either Doug's wiper noise detector or my test jig. You want to measure the problem before the repair or you won't have confidence in the repaired part.
• minimize material removal - keep the short straight section and angle the Dremel tool to remove just enough to pry off the top cover of the rounded section and two sides. There is a small gap at the top of the rounded section perfect for a small flat. Typically I grind at a 45 degree angle slowly and stop when I see a thin, light gray plastic line at several spots. Then use a small flat to pry off the thin, upper plastic part.
• retension the pickup arms - I've not found any evidence of debris in the parts I've cleaned. But with it open, it makes sense to wipe it down with contact cleaner. However, pre-repair tests, pressing the gray cover, suggests a 'gap' between the pickup arms and resistance traces. Don't go nuts but make sure all four pickup arms with their three wipes are retensioned. Sorry, I don't have a good metric on how much but don't go 'nuts' and bend them above the level of the gray cover ridge. You want them enough that they make a positive contact with the resistance traces on the gray cover but not so much that they'll scrape them off.
• use quality epoxy - I'm a fan of JB Weld due to its structural properties. Typically I use a small "C" clamp to hold the gray cover and then apply the epoxy around the edges. By keeping the JB Weld on the outside and not in the gap, it will be easy enough to rework if testing shows a problem. I typically use a flat toothpick to put the JB Weld exactly where it needs to go. If you want the gray cover permanently fixed, put a small amount of JB Weld in the gap before putting the cover under the clamp. Medium, light clamp pressure, just enough to hold the gray cover in the gap.
• Let it cure for 24 hours - keep the clamp on but wait until the paper plate sample used to mix the JB Weld is smooth and hard to the touch. DON'T rush this part.
• retest - regardless of which method is used, you want to know the part is repaired. Doug's noise detector or my jig approach lets you know the fix worked. Then put the accelerator back in the car.

Just take your time and do the job right. There is a lot of satisfaction that comes from fixing it yourself.

Bob Wilson

 

The main purpose of this thread is to get albokay fixed up, and perhaps I cannot contribute much to that with this response. But Bob and I know the outcome of our rebuilding work because we communicate directly with each customer. If they had problems, we'd know about it, and we could not conceal it.

Based on almost 9 years (gosh...) internetting Prius, I estimate 10% of the 2001 accel pedals failed. Some 2002 as well, but I would not not be sure that the rate is as high. I have never seem a bad one in a 2003. So, whenever they began producing the ...22 part number, it seems to have worked so far.

The actual failure data, is known to Toyota I am sure. I don't expect them to tell me it though.

Whatever the improvement was, whether it's' good enough' will ultimately be answered by years in successful service. I'm very glad that Toyota is now selling what appears to be an improved part. Those who wish to pay $500 or more for it should certainly do so.

 

This matches my experience but it makes no difference. Folks still have Prius they need to keep in service at affordable prices: good, fast, cheap, pick two of three.

Bob Wilson

 

A couple of questions:

Rebuilding involves, at an minimum, the replacement of wear items. However, from the description in this thread, it appears that the assembly is cut apart, the wiper tracks are cleaned up, the wiper arms are re-tensioned, and the assembly is glued back together, prior to testing.

What are you rebuilding?

Let's imagine that one of your refurbished accelerator pedals fails in service.

Is it possible that a customer would simply have the part replaced without telling you? And if a customer sells their car, is it possible that they might not instruct the buyer to notify you if your part fails?

I don't think an accurate estimate can be made. People generally don't log on to internet forums to report that their accelerator pedal assemblies are doing fine.

Would it not then be prudent to recommend a used accelerator pedal assembly from a 2003 vehicle to someone who did not have the means to replace their failing accelerator pedal with a new one? After all, no matter how carefully you cut apart and repair the failed part, you're still putting the old design back into service. Using a 2003 component neatly avoids that drawback.

And a used accelerator pedal assembly probably won't cost $250, either. More like $100, I'd guess. Given that the sole argument you have made for refurbishing accelerator pedals is that of price, wouldn't this be an even more desirable solution than the one you are recommending?

So am I.

$353 here, after about five minutes of searching online:

2001 Toyota PRIUS Accelerator Link - 78-01 1878

Sorry, but I still don't see a reason to recommend that anyone buy a refurbished accelerator pedal assembly. Again, we are talking about a safety item.

 

DTC P1120 shows that the accelerator pedal position sensor has a malfunction. I do not recognize P1110.

The answer for P1120 is to replace the accelerator pedal, and the preceding dialogue explored the pros and cons of buying a new part vs. a salvage part vs. a repaired one. It's your money and your choice.

 

jk450's link shows today's price for the assembly is $364.36. It is certainly one of your options to consider.

I do hope you consider doing the work yourself, if the local Toyota shop bids high on the labor. You need a 10-mm socket and 3 inch extension. You need to squirm into a somewhat unsual position. But you will R&R in 15 minutes tops.

If a functional replacement assembly does not cure this problem, I'll eat humble pie. However one does that on the internet. Because we have heard these hoofbeats far to many times to think 'zebra'.

But by all means please post the outcome. If you end up with a removed part, I imagine Bob W. might be willing to buy it. Or there may be another reader here who wants to know how these gadgets work? Could happen...

 

As you say that you love the car so much, please understand that it is quite easy to replace the accelerator pedal assembly yourself, which you can buy for $364 as cited above. The other maintenance items also are DIY if you have the energy and motivation to do so. None of the activities are that hard to do and there exist several posts regarding how to do them.