2010 Prius 200k on clock and hybrid battery on his way out. I keep getting the engine light on with P261B that relates to the water pump ...but only when the outside temperature is 17c or less.....in days when the outside temperature are over 18c it doesn't happen...! I'm clueless. Any ideas? Thanx Posted via the PriusChat mobile app.
I'm having same issue with 2010 prius 170K miles. It happened 3 times. Car losses power and check hybrid system, check engine, and yellow triangle lights appear. I pull over and then off engine. On another occassion, the overheating light flashed for 5 second and another day overheating light went on for about 5 mins. Eventually car runs and lights disappear. Autozone says code is P261B. I looked online and it could be several remedies in addition to replacing coolant pump. This is not for the hybrid engine. My hybrid tech says to replace engine coolant water pump for $450 but wanted to get anyone's thoughts on this issue before I go and spend this amount. It's strange because the car runs and lights are off.
Your tech is likely correct in that with P261b you need an engine water pump. Being that you've had the "check hybrid system" message and have variation in symptoms, I would have your tech verify codes with his hybrid aware scan tool. There is a chance the Autozone scanner only picked up the engine ecu code and doesn't recognize hybrid system ecu codes.
Did anyone ever tie this code to temperature outside? I got the code yesterday and shop today said they cannot find anything really wrong with the water pump - it is getting power and seems to be working. It was in high teens and low 20s yesterday and I idled on a phone call for 90 minutes, then drove 90 minutes / 100 miles, then idled for 30 minutes, then drove for about an hour before I saw the code. I never saw the red triangle just CEL and my reader said P261B. I drive rural miles in Minnesota winter and cannot afford to have some problem in the middle of nowhere. Any other explanation other than replacing the pump because it threw a code one day? 2017 Prius V has almost 167k on it.
