P0117 - how to diagnose?

Thanks, I had gotten that impression from other threads, but it's great to have it spelled out clearly. I'll definitely get the OEM pump - even if it weren't critical to keeping the engine healthy, it's not worth my time to install something that's likely to fail in the 5-ish years I'm hoping to keep the car. Yes, the coolant was replaced when the head gasket was done and I'll plan to reuse it.

Looking at parts places online, it seems like the OEM pump is Aisin WPT-190, and the only place that has it locally is NAPA for $561 which seems like a lot compared to Advance for $400 (but their website won't let me select the local store) and O'Reilly for $375 (but it's unavailable to order). I Googled it and found it on Amazon and eBay etc, this Amazon listing is only $148 and can be here in a few days.

Is there any reason not to get the one on Amazon? It appears to be the genuine new part, and I can wait a few days to save $400 over NAPA.

 

Okay, I was surprised at this and about to ask why someone didn't recommend taking it apart to see if the impeller has swelled/cracked and save $$$ by just replacing that. But then I answered my own question by reading a number of threads here searching for "impeller" and...

This thread by a person "with no mech training" sounds Iike a professor of mechanical engineering patiently explaining how these pumps fail, without the pretense. And this thread goes into plenty of (derogatory) detail about the Aisin water pumps with the Toyota logo ground off, like in the Amazon listing. Short version: the impeller often fails with tiny shards of plastic making it stick on the shaft but only at high load, like I'm experiencing, and also makes it nearly impossible to remove the impeller and might damage the steel shaft underneath. And the pumps with the Toyota logo ground off are genuine Aisin parts, but have failed QC checks, it's not just a legal compliance but a mechanical difference that puts them on Amazon.

So I went digging for parts from a dealer, remembering there was one I'd found years ago with remarkably cheap parts. It's McGeorge (since renamed Ourisman) in Richmond VA. But some threads on other Toyota related forums talked up Lithia as a West Coast alternative, which is my local dealer (they own all the Toyota dealerships in at least a 3-hour drive and are the local plutocrats of our small town, I try not to give them even more money) so I compared. Ourisman is $5 cheaper but charges $12 more in shipping than Lithia, at least online. The Lithia online parts is in Springfield for some reason, although the name comes from the lithium springs in my small hometown of Ashland, and the DeBoer family that started the dealership owns half the real estate in town, Alan was the mayor years ago, etc. Anyway, I'll call the Lithia Toyota in Medford tomorrow to see if I can pick it up there instead of waiting for delivery, and if they'll honor the $242 price online.

Also, since the CEL is off now and I think I understand the problem, I drove it around 15 miles each way (mostly freeway) today, it behaved normally. I don't imagine that the problem is gone, but I do think it's less urgent. My OBD readers should arrive tomorrow and I'll plug them in to see what I can find, before ordering parts. But I have to say how great it is to be guided by the wisdom of the age here - thanks everyone!

 

I saw plenty of that kind of back and forth about OEM vs Aisin vs whatever in the threads I found, and obviously they can't all be correct. I don't have a strong opinion on that and it seems clear that various people have had differing experiences. I just want to be sure the one I get is a new, genuine OEM part, and that I'm not paying too much. The theory about why the Toyota name is ground off the ones on Amazon and eBay may not be true, but it's plausible enough for me to avoid them.

Same with looking elsewhere first for parts; I don't have strong feelings against the DeBoers, but they obviously have more money than is good for anyone. I've clicked around on Amayama before but haven't ordered, and this time found the water pump is only $130 including shipping from Japan. But delivery is estimated to be more than two weeks away, and I'd rather pay more to get it next week.

I called Lithia Toyota of Medford since they're 20 minutes away, they have it on the shelf but quoted $362. They won't come down from that, and I can wait for shipping to get the $242 online price from what I assume is their corporate brother in Springfield. But I can also wait for shipping from Toyota Parts Deal, which is in the LA area and promises fast shipping. I remembered to add the thermostat to both sites which brings them both to $300 including shipping, so I chose Toyota Parts Deal, and it should be here next Tuesday. Which is fine because we'll be out of town all weekend anyway.

I'm looking forward to playing with the OBD readers when they arrive later today, but the evidence so far is enough for me to go ahead and order the pump and thermostat. Hopefully my next update will be a report that I replaced the water pump and everything works!

 

My OBD readers were delivered while I was making dinner, and I plugged in the Autel this evening. I can see why reviews of Bluetooth OBD readers talk about their speed - this one is said to be fast but I felt like I waited around for everything. I didn't poke around too much, just wanted to see if I could get the other code that the NAPA guy missed.
There it is! That P148F, coolant pump over revolution, is what I hoped the second code was. The sequence of events that led to the code being set, and the P0117 that I knew about, strongly implicated a water pump failure, enough so that I already ordered one. But I couldn't rule out that second code indicating a different reason for the P0117. Now with both codes, I have no doubt the water pump is failing. This kind of immediate information makes me wish I'd bought this thing years ago!

Also, I have to point out that the CEL went out sometime between last Friday afternoon (almost a week ago) and Monday, so when I went back to NAPA they wouldn't plug in the code reader. But this shows both two current codes, and the same two historical codes. I was under the impression that ECUs don't record any history on their own, so if there's no CEL on the dash, then a code reader won't find anything. But here I am with no CEL, still showing two current codes and the same two historical codes. This is a bit of an academic question for me now that I have a good code reader, but is this the norm? Do cars keep some record of recent codes or other historical info? Does it vary by brand or year? And if so, why don't the parts places plug in the code reader to catch something like what I see now?