P261C engine coolant pump b control circuit ow, what does this code mean

When there is conflicting information between the Prius repair manual and stuff on the internet, there isn't really conflicting information. The code is about the engine water pump circuits.

But keep in mind that the engine water pump circuits include more than just the pump itself. One of the most common diagnostic mistakes seen on PriusChat is when people get a code indicating a problem with some item X circuit, and immediately think "I should buy a new item X". The right move is to review what the trouble code is saying about the circuit, and electrically diagnose that, and fix whatever the problem turns out to be. The only times replacing item X will be the fix are when the circuit problem actually traces to the item itself.

 

Which is completely fair.

So I will do some more diag today. Maybe take it into an actual dealer to see what results they get and just fix it myself until I get get techstream running. But yeah, just have to trace things and see what's wrong.

 

Just do the trouble shooting steps in the PDF in post #18. You can save yourself the diagnostic fee at the dealership.

 

Open the hood, fuse books looks good. no blown fuses. Took off airflow box and inspected the waterpump for loose cables. Nothing there. Put the car in maintenance mode, tested the circulation of the inverter (sanity check) and engine coolant. No flow both looks still. Got back to the car and cranked the engine again picked up two new engine codes P0102, P0113 along with P261C.

Don't have a laptop to install techstream on yet.

Fun times :/

 

Those codes are for the two sensors that are combined in the "MAF sensor" assembly at the back of the air box. They would be unsurprising codes if you had unplugged that sensor and overlooked plugging it back in.

 

Made sure to plug it in before I put the engine filter in, but I'll check again.

 

Are the codes shown as current, or permanent?

If just permanent, they may have caught you at a time when you had it unplugged, which you've since corrected.

 

permanent.

 

Ok, so nothing that needs to be a distraction while dealing with the water pump circuits.

Later on, if you get tired of waiting for the P0102 and P0113 permanent codes to go away on their own, you can look into the confirmation driving patterns for them.