An open or poor connection in the coolant pump circuit (OBD-Codes.com, listed as likely). A failed coolant pump, electrically or mechanically, such as a stuck impeller (OBD-Codes.com, listed as likely). A failed water pump relay or bad relay connections (RepairPal; OBD-Codes.com also calls relays a common problem area). A wiring problem (RepairPal). A failed engine computer, which OBD-Codes.com calls unlikely (both sources).

Repair an open circuit, bad connection or wiring fault (both sources). Replace a failed water pump relay (RepairPal). Replace a failed electric coolant pump (OBD-Codes.com). Replace or reprogram the engine computer only after everything else checks out, since a new one must be programmed to the vehicle (both sources).

P261B🔧 Engine cooling (electric coolant pump)Stop and fix promptly

P261B: Coolant Pump B Control Circuit Range/Performance (Meaning, Causes, Fixes)

Q: What does P261B mean?

P261B means the engine computer has found a range or performance problem with the electric coolant pump labeled "B" or its control circuit. Electric coolant pumps show up most often on hybrids, and OBD-Codes.com names Ford, Honda, Nissan and Toyota. The usual causes are an open or poor connection in the pump circuit, a pump relay, or a failed pump (electrical or a stuck impeller), and less often the engine computer. Some engines use an electric coolant pump that the engine computer switches on and controls, instead of (or alongside) a belt-driven water pump. OBD-Codes.com explains that the computer decides when and how long to run pump "B" from coolant temperature, intake air temperature, engine rpm and A/C pressure readings, and that P261B is usually set by an electrical problem in the pump circuit but can also come from a mechanical problem such as a stuck impeller. RepairPal says the code sets when the computer does not detect the pump spinning at the speed it commanded. Related codes are P261A (circuit open), P261C (circuit low) and P261D (circuit high); P2600 to P2603 are the same codes for coolant pump "A".

Q: Can I keep driving with P261B?

Stop and fix promptly. Treat this as serious. RepairPal rates P261B as Urgent, and OBD-Codes.com calls it usually severe because it affects the cooling system and the engine computer can only partly make up for it. Watch the temperature gauge closely, and stop driving if the engine starts to overheat.

Reviewed 2026-10-24 · Based on 2 cited source(s)

What P261B means

Some engines use an electric coolant pump that the engine computer switches on and controls, instead of (or alongside) a belt-driven water pump. OBD-Codes.com explains that the computer decides when and how long to run pump "B" from coolant temperature, intake air temperature, engine rpm and A/C pressure readings, and that P261B is usually set by an electrical problem in the pump circuit but can also come from a mechanical problem such as a stuck impeller. RepairPal says the code sets when the computer does not detect the pump spinning at the speed it commanded. Related codes are P261A (circuit open), P261C (circuit low) and P261D (circuit high); P2600 to P2603 are the same codes for coolant pump "A".

Severity: can I keep driving?

Stop and fix promptly

Treat this as serious. RepairPal rates P261B as Urgent, and OBD-Codes.com calls it usually severe because it affects the cooling system and the engine computer can only partly make up for it. Watch the temperature gauge closely, and stop driving if the engine starts to overheat.

Common symptoms

Check engine light on
Engine overheating (OBD-Codes.com)
A/C not working properly (OBD-Codes.com)
Cooling fans running all the time, as the computer tries to compensate (OBD-Codes.com)

Likely causes

Roughly most to least common, based on the sources below. Your vehicle may differ.

An open or poor connection in the coolant pump circuit (OBD-Codes.com, listed as likely)
A failed coolant pump, electrically or mechanically, such as a stuck impeller (OBD-Codes.com, listed as likely)
A failed water pump relay or bad relay connections (RepairPal; OBD-Codes.com also calls relays a common problem area)
A wiring problem (RepairPal)
A failed engine computer, which OBD-Codes.com calls unlikely (both sources)

Diagnostic steps you can do

⚠ Before you start

Work on a cool engine, parked on level ground with the parking brake set. Never work under a car supported only by a jack.

Read all stored codes and check the coolant level with the engine cold. Never open a hot radiator or coolant reservoir cap.
Look up technical service bulletins for your vehicle first; OBD-Codes.com notes it may be a known issue with a known fix.
Find coolant pump "B" with your service manual. OBD-Codes.com says it may be on the front or top of the engine, in a wheel well or against the firewall.
Inspect the pump connector and wiring for rubbing, bare wires, burn marks, melted plastic or green corrosion on the terminals. Clean the terminals with electrical contact cleaner if needed, let them dry and apply electrical grease.
Check the pump relay and its connections, which OBD-Codes.com calls the most common problem area along with the wiring.
Clear the code and see if it returns. If it does, OBD-Codes.com describes testing the pump motor resistance with a multimeter (it should not be open or shorted; check your vehicle's spec), then checking for 12 volts and a good ground at the pump while a scan tool commands it on.

Typical fixes

Repair an open circuit, bad connection or wiring fault (both sources)
Replace a failed water pump relay (RepairPal)
Replace a failed electric coolant pump (OBD-Codes.com)
Replace or reprogram the engine computer only after everything else checks out, since a new one must be programmed to the vehicle (both sources)

Repair costs vary widely by vehicle, region, parts brand and shop, so we don't quote prices. Get a written estimate after diagnosis.

🛠 When to call a pro

The engine is overheating or the temperature gauge is climbing
It's a hybrid and you aren't sure which pump or cooling loop the code refers to
You need a scan tool that can command the coolant pump on for testing
The code returns after you've checked the wiring, connector and relay

Where to buy

Plain search links. Always match parts to your exact year, make, model and engine.

OBD2 scanners on Amazon Parts at Advance Auto Parts catalog at RockAuto

FAQs

Is P261B serious?

Yes. RepairPal rates it Urgent, and OBD-Codes.com calls it usually severe because it affects engine cooling. If the temperature gauge climbs, pull over and shut the engine off to avoid engine damage.

Can I drive with P261B?

Only with care, and not if the engine is overheating. OBD-Codes.com says the computer may run the cooling fans all the time to partly compensate, but it can't fully make up for a pump that isn't working.

Which vehicles get P261B?

Vehicles with electric coolant pumps. OBD-Codes.com says it shows up more often on certain hybrids from Ford, Honda, Nissan and Toyota, and its forum includes a 2012 Toyota Camry Hybrid with P261B and P261C.

Do the sources agree on P261B?

Mostly. Both rate it serious. RepairPal says it sets when the pump isn't spinning at the commanded speed and lists the computer, the water pump relay and wiring as causes. OBD-Codes.com describes it as usually an electrical circuit problem that can also be mechanical, lists an open circuit and a failed pump as the likely causes, and mentions relays in its repair steps rather than its cause list. RepairPal doesn't list the pump itself as a cause.

How much does it cost to fix P261B?

Neither source gives a repair cost. It can range from cleaning a connector or replacing a relay to replacing the electric coolant pump, so get a written estimate after diagnosis.

Sources

Last reviewed 2026-10-24. Code definitions and repair steps can vary by manufacturer. Confirm with your vehicle's service information.