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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

for Preparation Click here

DESCRIPTION

The ECM controls the engine water pump assembly by calculating the necessary amount of coolant flow based on engine coolant temperature, engine speed and vehicle speed information. The speed of the engine water pump assembly is controlled steplessly using a duty cycle signal sent from the ECM. This optimal control enhances warm-up performance and reduces cooling losses, thus reducing the specific fuel consumption of the engine.

DTC No.	DTC Detection Condition	Trouble Area
P261B	Engine water pump assembly speed is less than 900 rpm while the engine water pump assembly is operating (1 trip detection logic).	Open or short in engine water pump assembly circuit Engine water pump assembly ECM
P261C	Engine water pump assembly output voltage is less than specified value while the engine water pump assembly is operating (1 trip detection logic).	Short in engine water pump assembly circuit Engine water pump assembly ECM
P261D	Engine water pump assembly output voltage is higher than specified value while the engine water pump assembly is operating (1 trip detection logic).	Open in engine water pump assembly circuit Engine water pump assembly ECM

MONITOR DESCRIPTION

The ECM calculates the speed of the engine water pump assembly using a duty cycle signal sent from the engine water pump assembly. When the speed of the engine water pump assembly becomes less than 900 rpm while it is operating, the ECM detects the malfunction and stores DTC P261B.
The engine water pump assembly operates steplessly based on a duty cycle signal sent from the ECM. If actual drive duty cycle ratio does not correspond to the target drive duty cycle of the engine water pump assembly, the ECM detects the malfunction.

MONITOR STRATEGY

Required Sensors/Components (Main)	Engine water pump assembly
Frequency of Operation	Continuous

CONFIRMATION DRIVING PATTERN

Connect the intelligent tester to the DLC3.
Turn the power switch on (IG) and turn the tester on [A].
Clear the DTCs (even if no DTCs are stored, perform the clear DTC operation).
Turn the power switch off and wait for 30 seconds.
Turn the power switch on (IG) and turn the tester on.
Put the engine in inspection mode (maintenance mode) (Click here).
Start the engine and warm it up (until the engine coolant temperature is 75°C (167°F) or higher) [B].
Idle the engine for 20 seconds or more [C].
Enter the following menus: Powertrain / Engine and ECT / DTC.
Read the pending DTCs [D].
HINT:
1. If a pending DTC is output, the system is malfunctioning.
2. If a pending DTC is not output, perform the following procedure.
Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
Input the DTC: P261B, P261C or P261D.

Check the DTC judgment result.

Tester Display	Description
NORMAL	DTC judgment completed System normal
ABNORMAL	DTC judgment completed System abnormal
INCOMPLETE	DTC judgment not completed Perform driving pattern after confirming DTC enabling conditions
UNKNOWN	Unable to perform DTC judgment Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

HINT:

If the judgment result shows NORMAL, the system is normal.
If the judgment result shows ABNORMAL, the system has a malfunction.
If the judgment result shows INCOMPLETE or UNKNOWN, perform steps [C] again.

WIRING DIAGRAM

INSPECTION PROCEDURE

NOTICE:

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

HINT:

Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.

1.PERFORM ACTIVE TEST USING INTELLIGENT TESTER (ACTIVATE THE ELECTRIC WATER PUMP)

Connect the intelligent tester to the DLC3.

Turn the power switch on (IG).

Turn the tester 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).

Go to step 4

OK

2.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:

Tester Connection	Condition	Specified Condition
D13-2 (NWP) - A60-11 (WPI)	Always	Below 1 Ω
D13-4 (SWP) - A60-10 (WPO)	Always	Below 1 Ω
D13-2 (NWP) or A60-11 (WPI) - Body ground	Always	10 kΩ or higher
D13-4 (SWP) or A60-10 (WPO) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

3.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)

Text in Illustration
*a	Front view of wire harness connector (to Engine Water Pump Assembly)

REPLACE ECM (Click here)

REPLACE ENGINE WATER PUMP ASSEMBLY

4.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)

Text in Illustration
*a	Front view of wire harness connector (to Engine Water Pump Assembly)

Go to step 9

OK

5.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:

Tester Connection
Condition
Specified Condition
D13-5 (PGND) - Body ground
Always
Below 1 Ω

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

6.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:

Tester Connection	Condition	Specified Condition
D13-2 (NWP) - A60-11 (WPI)	Always	Below 1 Ω
D13-4 (SWP) - A60-10 (WPO)	Always	Below 1 Ω
D13-2 (NWP) or A60-11 (WPI) - Body ground	Always	10 kΩ or higher
D13-4 (SWP) or A60-10 (WPO) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

7.REPLACE ENGINE WATER PUMP ASSEMBLY

Replace the engine water pump assembly (Click here).

NEXT

8.CHECK WHETHER DTC OUTPUT RECURS (DTC P261B, P261C OR P261D)

Connect the intelligent tester to the DLC3.

Turn the power switch on.

Turn the tester on.

Clear the DTCs.

Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.

Enter the following menus: Powertrain / Engine and ECT / DTC.

Read the DTCs.
Result
Result
Proceed to
DTC P261B, P261C or P261D is output
A
DTC is not output
B

Result
Result	Proceed to
DTC P261B, P261C or P261D is output	A
DTC is not output	B

END

REPLACE ECM (Click here)

9.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

REPLACE ENG W/P RELAY

OK

10.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:

Tester Connection
Condition
Specified Condition
ENG W/P relay terminal 5 - D13-1 (+B)
Always
Below 1 Ω
ENG W/P relay terminal 5 or D13-1 (+B) - Body ground
Always
10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

11.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

REPAIR OR REPLACE HARNESS OR CONNECTOR (ENG W/P RELAY - AUXILIARY BATTERY)

OK

12.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:

Tester Connection
Condition
Specified Condition
ENG W/P relay terminal 1 - Body ground
Always
Below 1 Ω

REPAIR OR REPLACE HARNESS OR CONNECTOR

REPAIR OR REPLACE HARNESS OR CONNECTOR (ENG W/P RELAY - EFI MAIN RELAY)

Tester Connection	Switch Condition	Specified Condition
D13-2 (NWP) - Body ground	Power switch on (IG)	11 to 14 V

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

for Preparation Click here

DESCRIPTION

MONITOR DESCRIPTION

MONITOR STRATEGY

CONFIRMATION DRIVING PATTERN

WIRING DIAGRAM

INSPECTION PROCEDURE