Swapping in a Gen 4 Prius' 2ZR Engine into the Prius v

I just want to run a long enough to make sure that there is power actually going to the pump my next step would be once I confirm there is power is to remove the pump that's installed and apply voltage to it to see if it spins or not which pins do I need to apply voltage to do you know

 

You give it +12 on pin 1 and ground pin 5, then you send it a 25 Hz pulse input on pin 4 where the duty cycle of the pulses tells it how fast you want it to spin. 50% duty cycle asks for 3000 rpm. I linked earlier to another thread with more information.

I'm not sure the duty cycle actually maps to rpm directly; in fact I'm pretty sure it doesn't. 50% probably just means roughly "half power" and should mean around 3000 rpm when it is immersed and pumping coolant, but might turn out quite a bit faster if it isn't.

 

ok plugged in old pump and it ran so my new pump is bad. got one on the way. after cleaning the EGR ports on the intake im now getting P0441 P0455 & P0403 so two are the evap and one the EGR. I did break a corner of the vacuum evap purge valve thing I put PVC glue to close the hole seemed to work but still getting the error. so I have two questions. does EGR have a fuse if so where is it? and is there a way to test this grey and black vacuum thing. All I did was clean the intake and pressure was the egr cooler. Fix one break two urgh.. The intresting thing is the car runs fine now issues or rough idle

 

Does anyone know if the EGR has a fuse

 

I do

 

Ok good to know.

 

Can I apply 12v to the purge valve to test it? Or is that too much voltage.

 

Have you taken the time to look any of your codes up in the manual yet?

You have a lot of questions whose answers all are there.

About the EGR, you may find some of what you're looking for in this older post here. Of course that just came straight from the manual.

You might be able to find other posts where other people have already extracted from the manual enough evap information for you to work with.

It's just that as the number of questions you have about things that are in the manual grows, the more advantageous you will probably find it to be able to answer them yourself.

 

Reading the Manual as we speak its just im not very good at reading the electrical diagrams but I have more time than money so here we go.

 

I would check the EFI and IGN fuses.

 

thanks will do.

 

Hold the phone a sec. I wasn't noticing the gorilla behind the basketball court.

You've got a P261C? The "fail-safe chart" in the manual shows that the ECM responds to P261C or D in a way you might not guess:



The third column is what the ECM does, as its "fail-safe operation", when the corresponding code is logged. (The final column is what resets the fail-safe operation.)

So both of these codes mean something is wrong with the pump tachometer circuit. It is stuck low or stuck high, respectively. Either way, the ECM can't tell how fast the pump is running.

So what does it do when it can't tell how fast the pump is running? It stops telling the pump to run!

I am having a lot of trouble right now guessing how they chose that as the "fail-safe operation".

But it certainly explains how having a P261C code could end up leading to engine overheating, whether or not the code is a problem with the pump itself. The code could be caused by a problem in the tachometer circuitry inside the pump itself, but it doesn't have to be. It could be any run-of-the-mill wiring or connector issue between NWP at the pump and WPI at the ECM. Either way, because the ECM responds to the code by not running the pump, this could lead to overheating even if the code isn't the pump's fault at all.

So the main water pump order of business would just be to track down what is causing that stuck-low tachometer line.

 

Thanks for that it was driving me nuts as the car overheats but when the pump is visually inspected when i turn IGN to on I see the impeller run. New pump will be here Monday I will install it hope for the best if issue persists I will still take it to the shop get a diag for 95 bucks and do the work myself.

 

Is it a Toyota pump? That's a supplier I wouldn't be concerned about.

Your bench testing will depend on how thoroughly you want to test it.

There's a five-pin connector, with pin 3 unused. Pin 1 goes to a +12 volt battery supply and pin 5 to ground. Pin 4 is used to tell the pump how fast to run, by sending pulses at 25 Hz, where the duty cycle (percent of time the pulsed signal is high) is the proportion of full speed that you want. Pin 2 is a tachometer output from the pump, a square wave at two cycles per pump rev. Whatever frequency in Hz you measure for that wave, multiply by 30 and you've got the pump speed in RPM.

You can see if you want to thoroughly test that everything works, you will need a stout source of 12 volt power, a function generator capable of generating 25 Hz pulses with a duty cycle you adjust, and if not an oscilloscope for the tachometer signal, at least a frequency counter that can read you off the frequency in Hz.

More details: the pump has an internal pullup to +12 on pin 4, so the way you send it that speed-control pulse train is by pulling it down for the low parts. This of course gives you a crude way to test the pump only at full speed: that's what it will think you want if you just leave pin 4 unconnected.

By contrast, the pump depends on an external pullup on the tachometer output (normally supplied by the ECM). The pump sends the tach signal by pulling it down. If not connected to the ECM, you won't see any signal on pin 2 when the pump rotates unless you have supplied your own pullup resistor to +12.

You could maybe test the tachometer output without a scope or frequency counter, by just powering up the pump and telling it not to run (by tying the pin 4 input to ground) and turning the impeller slowly by hand, looking for the tach output to go on-off-on-off each time you turn the impeller one full turn around. That way you could just use a voltmeter, or even a resistor and an LED. Mind, I think this would work, but I've never done it.

Voltmeter might be good, because your car is complaining (P261C) about how low the tach signal goes. You might want to pay special attention to the voltage floor of that tach waveform, and have a known-good Toyota pump to compare it to.

I should mention that this kind of pump may depend critically on being immersed in coolant for its lubrication; it is possible that there could be in fact no amount of time that it can be run dry without damage. Also, without the work of water to pump, it could hit rpms far higher than any it is designed to hit while pumping.

If you have a spare 2ZR timing cover, you could probably mount the pump in it and cobble something up with a thermostat elbow and a bucket and some hoses, and give it something to pump. No need to fuss with the gaskets; a little leakage from a test jig just makes it more fun.

 

Thank you for this .....time and money. this pump was 200 bucks I can break it and not be able to send it back if indeed there is an issue with it. I can pay a tech to diagnose for 95 then I would know exactly what's wrong. I want to do this but the risk I high. Thanks for bringing some clarity to what I was asking, I know now I don't want to do due to the risk. I may do it with the old gen three pump. by the way in an attempt to check the motor I pulled on the impeller and the top portion came off. is it now broken? this is on the old gen three pump.

 

You mean like so?



If so, yep, toast.

Regarding diagnosis by a tech for $95, keep in mind that might not be guaranteed either. As I think you're noticing from the way these topics have gone, given the kinds of control and feedback circuits used on these modern parts, they exist as much in the electronics-tinkerer world as the wrench-head world. Some techs in some mechanic shops will be there and some won't, and with those you might be back to "well, why don't we put a new one in (on your nickel) and see what happens?" Or the $95 might be for an initial look and checking for any codes, with further investigation at an hourly rate.

 

YUp like that its toast. Good thing its the gen3 pump it had 190K on so likely soon to fail soon. But I think installing it would tell me if i have electrical issues. My thinking is its a known good pump so If I clear codes install it and see if codes come back it does not need to actually work hard as im not leaving the driveway. only to see if my codes come back for the pump. what do you think?

 

I've forgotten the year of your Gen 3. With the impeller busted like that, the pump is likely to overrev because it won't really be moving water much. In a 2010 that won't set a code (they didn't realize their impellers were going to bust, so who would expect runs-too-fast to be a problem?). For 2011 and later, they added a code P148F for that.

It might tell you something, how much I don't know. You could end up investing as much effort in trying to find ways around directly testing the issues indicated by the codes you have as it would take to directly test them.

 

Ok one going to give it another shot. ONe issue at a time. The pump. codes are P261B and 261C. Side note will the gen 3 pump work in the Gen 4 ? or is that a nono. Going to go through former posts see what I can gleam. then go over the PDF

 

I see the part number changed 2015 to 2016, so it's a fair question. Have you looked for any section in the 2016 New Car Features manual that details any changes?