Hi guys, I have 2008 Prius, I had P2601 lights on. Then I have replaced Coolant flow control valve ( genuine part) and check engine light went out. After driven 400 miles lights came back with same code P2601. Do you guys have any advice ? Any help will appreciated.
looks like there are a few possibilities. maybe something is shorting out the pump: p2601-obd-ii-trouble-code-coolant-pump-control-circuit-range-performance-by-spencer-clayton
There is a problem when looking up manufacturer-specific codes on the internet and coming up with generic advice. I'm sure that if you took your car to the facility in that link they would do a grand job of checking the Toyota-specific meaning of that code. While P2601 does relate to a water pump, it not the auxilary engine water pump, but rather CHRS Coolant Pump. The ECU has received feedback data that it interprets as "control circuit range error(s) or performance issues. Areas of interest are: CHS water pump - CHS water pump relay Open or short in CHS water pump circuit (my emphasis!) ECM Following the repair manual (more info) for this DTC should pinpoint the particular area so a correct repair can be made.
As others have mentioned, that code is not (directly) for the coolant control valve. It sets when the ECM doesn't see the reading that it expects from the Coolant Heat Storage temperature sensor. When you turn the car off, hot coolant is pumped into the "thermos" tank in the left front fender. When you ready the car the next day (or 3), that still hot coolant is pumped back into the engine. If you have a capable scantool, you can monitor Engine Coolant Temperature and "water outlet" (CHS) temperature readings. (With a fancier capable scantool you can bidirectionally turn the CHS water pump on at anytime and see if it works). First "start up" in the morning, press power twice (no foot on brake) - ignition ON. Go to climate control and turn the blower OFF. Now foot on brake + power to go ready. The CHS pump should run for 3-5 seconds before the engine starts up. Here's a graph of the two temperature sensors. Both go increase by about 100°F then the RPM's show the ICE starting. Posted via the PriusChat mobile app.
