P261C on Toyota: How to Diagnose & Fix
Coolant Pump "B" Control Circuit Low
1 Toyota model · 1 documented issue · 1 critical · $250-$800 repair
P261C on Toyota by model: symptoms, diagnosis and fix
Unlike a belt-driven pump, the 2ZR-FXE engine coolant pump is a brushless electric unit commanded by duty cycle from the ECM. The internal motor/controller degrades and the pump slows or stops, so coolant stops circulating through the engine. The ECM detects the speed feedback falling below threshold and sets P261B (or P261C), lights the check engine and hybrid warning lights, and will shut the gas engine down to protect it, leaving the car crawling on battery only. Toyota addressed it with T-SB-0143-10 and a revised pump design; it is one of the most-reported repairs on third-gen Prius, Prius v, Prius c and Lexus CT200h.
Common Symptoms
- Check engine light with hybrid system warning
- Engine temperature climbing, overheat message
- No coolant movement visible in the reservoir with engine running
- Gas engine shuts down or car enters limp mode
- Heater blows cold
How to Fix
Confirm with the code plus a visual check of coolant flow in the reservoir with the engine running. Replace the electric engine water pump with the updated Aisin/Toyota unit (do not reuse the old O-ring), refill and run the Techstream/manual air-bleed procedure - trapped air in this system will cause repeat overheat codes and can mimic a second pump failure. It is a 1-2 hour job accessible from the passenger side of the engine. Cheap no-name aftermarket pumps are a common repeat-failure complaint.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Aisin WPT-190 electric engine water pump
replace an engine coolant pump proven slow, electrically faulty or non-operational after circuit diagnosis Fitment/availability: 2010-2015 Prius 1.8L 2ZR-FXE; Aisin also catalogs the branch for 2012-2015 Prius Plug-in and 2012-2018 Prius…
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Sources for this issue (3)
P261C code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P261C mean on a Toyota?
P261C stands for "Coolant Pump "B" Control Circuit Low." This code indicates the engine control module detected an abnormally low voltage (a short to ground) on the control circuit for electric coolant pump "B." That auxiliary pump circulates coolant to support engine, turbocharger, hybrid, or A/C cooling. A low/short condition means the circuit is not behaving correctly, and the computer can lose reliable control of the pump, which risks inadequate cooling and overheating of the affected system. On Toyota it is documented across 1 model: Prius.
What are the most common causes of P261C?
The most common causes of P261C are: Control wiring shorted to ground, Internally shorted/failed coolant pump, Corroded or damaged pump connector, Chafed wiring contacting chassis ground, Faulty pump relay or power circuit, ECM/PCM driver circuit fault (rare). The specific cause varies by vehicle.
How much does it cost to fix P261C on a Toyota?
Published repair estimates on Toyota range from $250 to $800 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P261C on a different make?
View P261C across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.