Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC P261B: Engine Coolant Pump "B" Control Malfunction; DTC P261C: Engine Coolant Pump "B" Control Circuit Low; DTC P261D: Engine Coolant Pump "B" Control Circuit High: Procedure
- PERFORM ACTIVE TEST USING TECHSTREAM (ACTIVATE THE ELECTRIC WATER PUMP)
- Connect the Techstream to the DLC3.
- Turn the power switch on (IG).
- Turn the Techstream on.
- Enter the following menus: Powertrain / Engine and ECT / Active Test / Activate the Electric Water Pump.
- Touch the engine water pump assembly and check that the pump is operating (vibrating).
OK
The engine water pump assembly is operating (vibrating).
NG → See step 4
OK: Go to next step
- CHECK HARNESS AND CONNECTOR (ENGINE WATER PUMP ASSEMBLY - ECM)
HINT:
Confirm a good connection at the engine water pump assembly and ECM connectors.
- Disconnect the engine water pump assembly connector.
- Disconnect the ECM connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open)
Tester Connection Condition Specified Condition D13-2 (NWP) - A57-11 (WPI) Always Below 1 Ω D13-4 (SWP) - A57-10 (WPO) Always Below 1 Ω Standard Resistance (Check for Short)
Tester Connection Condition Specified Condition D13-2 (NWP) or A57-11 (WPI) - Body ground Always 10 kΩ or higher D13-4 (SWP) or A57-10 (WPO) - Body ground Always 10 kΩ or higher
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: Go to next step
- CHECK ECM (WPI VOLTAGE)
- Disconnect the engine water pump assembly connector.
- Turn the power switch on (IG).
- Measure the voltage according to the value(s) in the table below.
Standard Voltage
Tester Connection Switch Condition Specified Condition D13-2 (NWP) - Body ground Power switch on (IG) 11 to 14 V TEXT IN ILLUSTRATION*a Front view of wire harness connector
(to Engine Water Pump Assembly)
NG → See step 13
OK → See step 14
- CHECK ENGINE WATER PUMP ASSEMBLY (POWER SOURCE)
HINT:
Confirm a good connection at the engine water pump assembly and ECM connectors.
- Disconnect the engine water pump assembly connector.
- Turn the power switch on (IG).
- Measure the voltage according to the value(s) in the table below.
Standard Voltage
Tester Connection Switch Condition Specified Condition D13-1 (+B) - Body ground Power switch on (IG) 11 to 14 V TEXT IN ILLUSTRATION*a Front view of wire harness connector
(to Engine Water Pump Assembly)
NG → See step 9
OK: Go to next step
- CHECK HARNESS AND CONNECTOR (ENGINE WATER PUMP ASSEMBLY - BODY GROUND)
- Disconnect the engine water pump assembly connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open)
Tester Connection Switch Condition Specified Condition D13-5 (PGND) - Body ground Always Below 1 Ω
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: Go to next step
- CHECK HARNESS AND CONNECTOR (ENGINE WATER PUMP ASSEMBLY - ECM)
- Disconnect the engine water pump assembly connector.
- Disconnect the ECM connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open)
Tester Connection Condition Specified Condition D13-2 (NWP) - A57-11 (WPI) Always Below 1 Ω D13-4 (SWP) - A57-10 (WPO) Always Below 1 Ω Standard Resistance (Check for Short)
Tester Connection Condition Specified Condition D13-2 (NWP) or A57-11 (WPI) - Body ground Always 10 kΩ or higher D13-4 (SWP) or A57-10 (WPO) - Body ground Always 10 kΩ or higher
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: Go to next step
- REPLACE ENGINE WATER PUMP ASSEMBLY
- Replace the engine water pump assembly. Refer to REMOVAL .
NEXT: Go to next step
- CHECK WHETHER DTC OUTPUT RECURS (DTC P261B, P261C OR P261D)
- Connect the Techstream to the DLC3.
- Turn the power switch on.
- Turn the Techstream on.
- Put the engine in inspection mode (maintenance mode). Refer to INSPECTION MODE PROCEDURE .
- Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.
- Enter the following menus: Powertrain / Engine and ECT / Trouble codes.
- Read the DTCs.
Result
Result Proceed to DTC P261B, P261C or P261D is output A DTC is not output B
B → END
A → See step 13
- INSPECT ENG W/P RELAY
- Remove the ENG W/P relay from the engine room relay block.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition 3 - 5 No auxiliary battery voltage applied between terminals 1 and 2 10 kΩ or higher 3 - 5 Auxiliary battery voltage applied between terminals 1 and 2 Below 1 Ω
NG → REPLACE ENG W/P RELAY
OK: Go to next step
- CHECK HARNESS AND CONNECTOR (ENG W/P RELAY - ENGINE WATER PUMP ASSEMBLY)
- Remove the ENG W/P relay from the engine room relay block.
- Disconnect the engine water pump assembly connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open)
Tester Connection Condition Specified Condition ENG W/P relay terminal 5 - D13-1 (+B) Always Below 1 Ω Standard Resistance (Check for Short)
Tester Connection Condition Specified Condition ENG W/P relay terminal 5 or D13-1 (+B) - Body ground Always 10 kΩ or higher
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: Go to next step
- CHECK ENG W/P RELAY (POWER SOURCE)
- Remove the ENG W/P relay from the engine room relay block.
- Measure the voltage according to the value(s) in the table below.
Standard Voltage
Tester Connection Condition Specified Condition ENG W/P relay terminal 3 - Body ground Always 11 to 14 V TEXT IN ILLUSTRATION*1 Engine Room Relay Block *2 ENG W/P Relay
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (ENG W/P RELAY - AUXILIARY BATTERY)
OK: Go to next step
- CHECK HARNESS AND CONNECTOR (ENG W/P RELAY - BODY GROUND)
- Remove the ENG W/P relay from the engine room relay block.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open)
Tester Connection Condition Specified Condition ENG W/P relay terminal 1 - Body ground Always Below 1 Ω
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK → REPAIR OR REPLACE HARNESS OR CONNECTOR (ENG W/P RELAY - EFI MAIN RELAY)
- REPLACE ECM. Refer to REMOVAL
- REPLACE ENGINE WATER PUMP ASSEMBLY. Refer to REMOVAL
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.