Last Modified: 05-13-2024 6.11:8.1.0 Doc ID: RM100000001NG0K
Model Year Start: 2021 Model: Corolla Hatchback Prod Date Range: [04/2020 - 06/2020]
Title: M20A-FKS (ENGINE CONTROL): SFI SYSTEM: P26CB71; Engine Coolant Pump Actuator Stuck; 2021 MY Corolla Corolla Hatchback [04/2020 - 06/2020]

DTC

P26CB71

Engine Coolant Pump Actuator Stuck

DESCRIPTION

Refer to DTC P26CA12.

Click here 2020 - 2022 MY Corolla Corolla Hatchback [03/2019 - 09/2022]; M20A-FKS (ENGINE CONTROL): SFI SYSTEM: P26CA12; Engine Coolant Pump Circuit Short to Battery+

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Memory

Note

P26CB71

Engine Coolant Pump Actuator Stuck

Even though an operation request signal is being output, the engine water pump assembly does not rotate* (1 trip detection logic).

  • Lack of engine coolant
  • Engine coolant leak
  • Engine water pump assembly (water inlet housing)
  • ECM

Comes on

DTC stored

  • SAE Code: P26CB
  • DTC for Mexico Models: Applies

*: As the frequency signal (WPI) is 4 Hz when the engine water pump assembly is stopped to enable the ECM to detect an open or short in the signal line, the engine water pump assembly speed will be displayed as approximately 160 rpm even when the pump is stopped. If there is an open in the WPI circuit, the engine water pump speed will be displayed as 0 rpm.

Related Data List

DTC No.

Data List

P26CB71

  • Coolant Temperature
  • Electric Water Pump Target Speed
  • Electric Water Pump Speed

MONITOR DESCRIPTION

The ECM receives a frequency signal (WPI) from the engine water pump assembly and calculates the speed of the engine water pump assembly. The ECM outputs an operation duty signal (WPO) to steplessly control the speed of the engine water pump assembly. If the duty signal (WPI) indicates that the engine water pump assembly is stopped even though the ECM is outputting an operation duty signal (WPO), the ECM judges that the engine water pump assembly is stuck and stores this DTC.

As the frequency signal (WPI) is 4 Hz when the engine water pump assembly is stopped to enable the ECM to detect an open or short in the signal line, the engine water pump assembly speed will be displayed as approximately 160 rpm even when the pump is stopped.

MONITOR STRATEGY

Related DTCs

P26CB: Engine water pump motor lock

Required Sensors/Components (Main)

Engine water pump assembly

Required Sensors/Components (Related)

-

Frequency of Operation

Continuous

Duration

Less than 65 seconds

MIL Operation

Immediate

Sequence of Operation

None

TYPICAL ENABLING CONDITIONS

All of the following conditions are met

-

Engine coolant temperature

-10 °C (-50 °F) or higher

Engine

Running

Battery voltage

Higher than 8 V (for Hatchback)

8 V or higher (for Sedan)

Engine coolant temperature sensor malfunction (P0117, P0118)

Not detected

Engine water pump (IN) malfunction (P26CA)

Not detected

Engine water pump (OUT) malfunction (P26CC, P26CD)

Not detected

TYPICAL MALFUNCTION THRESHOLDS

All of the following conditions are met

15 seconds or more

Out of step operation*

Active

Engine water pump (IN) motor speed

100 rpm or higher

Engine water pump (IN) motor speed

Less than 170 rpm

*: Out of step operation is active when following condition are met

2 second (for Hatchback)

2 second or more (for Sedan)

Engine water pump output duty ratio

30 to 85%

Engine water pump (IN) motor speed

100 rpm or higher

Engine water pump (IN) motor speed

Less than 170 rpm

CONFIRMATION DRIVING PATTERN

HINT:

  • After repair has been completed, clear the DTC and then check that the vehicle has returned to normal by performing the following All Readiness check procedure.

    Click here 2019 - 2022 MY Corolla Corolla Hatchback [06/2018 - 09/2022]; M20A-FKS (ENGINE CONTROL): SFI SYSTEM: DTC CHECK / CLEAR

  • When clearing the permanent DTCs, refer to the "CLEAR PERMANENT DTC" procedure.

    Click here 2019 - 2022 MY Corolla Corolla Hatchback [06/2018 - 09/2022]; M20A-FKS (ENGINE CONTROL): SFI SYSTEM: DTC CHECK / CLEAR

  1. Connect the Techstream to the DLC3.
  2. Turn the ignition switch to ON.
  3. Turn the Techstream on.
  4. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
  5. Turn the ignition switch off and wait for at least 30 seconds.
  6. Turn the ignition switch to ON [A].
  7. Turn the Techstream on.
  8. Move the shift lever to P or neutral [B].
  9. Start the engine and maintain the engine speed at 2500 rpm or more for at least 40 seconds [C].
  10. Enter the following menus: Powertrain / Engine / Trouble Codes [D].
  11. Read the pending DTCs.

    HINT:

    • If a pending DTC is output, the system is malfunctioning.
    • If a pending DTC is not output, perform the following procedure.
  12. Enter the following menus: Powertrain / Engine / Utility / All Readiness.
  13. Input the DTC: P26CB71.
  14. Check the DTC judgment result.

    Techstream 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

    HINT:

    • If the judgment result is NORMAL, the system is normal.
    • If the judgment result is ABNORMAL, the system has a malfunction.
    • If the judgment result is INCOMPLETE, perform steps [B] through [D] again.
    • [A] to [D]: Normal judgment procedure.

      The normal judgment procedure is used to complete DTC judgment and also used when clearing permanent DTCs.

    • When clearing the permanent DTCs, do not disconnect the cable from the battery terminal or attempt to clear the DTCs during this procedure, as doing so will clear the universal trip and normal judgment histories.

WIRING DIAGRAM

Refer to DTC P26CA12.

Click here 2020 - 2022 MY Corolla Corolla Hatchback [03/2019 - 09/2022]; M20A-FKS (ENGINE CONTROL): SFI SYSTEM: P26CA12; Engine Coolant Pump Circuit Short to Battery+

CAUTION / NOTICE / HINT

HINT:

  • As the frequency signal (WPI) is 4 Hz when the engine water pump assembly is stopped to enable the ECM to detect an open or short in the signal line, the engine water pump assembly speed will be displayed as approximately 160 rpm even when the pump is stopped.
  • Read Freeze Frame Data using the Techstream. The ECM records vehicle and driving condition information as Freeze Frame Data the moment a DTC is stored. When troubleshooting, Freeze Frame Data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.

PROCEDURE

1.

CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P26CB71)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine / Trouble Codes.

(e) Read the DTCs.

Powertrain > Engine > Trouble Codes

Result

Proceed to

DTC P26CB71 is output

A

DTC P26CB71 and P26CE37 are output

DTC P26CB71 and other DTCs are output

B

B

GO TO DTC CHART

A

2.

CHECK ENGINE COOLANT LEVEL IN RESERVOIR TANK

(a) Check that the engine coolant level is between the FULL and LOW lines.

for Fully Sealed Type: Click here 2020 - 2025 MY Corolla Corolla Hatchback [09/2019 -        ]; M20A-FKS (COOLING): COOLING SYSTEM: ON-VEHICLE INSPECTION+

for Non-Fully Sealed Type: Click here 2020 - 2025 MY Corolla Corolla Hatchback [09/2019 -        ]; M20A-FKS (COOLING): COOLING SYSTEM: ON-VEHICLE INSPECTION+

Result

Proceed to

Engine coolant level is above the LOW line

A

Engine coolant level is below the LOW line

B

A

GO TO STEP 6

B

3.

CHECK FOR ENGINE COOLANT LEAKS

(a) Check the areas around the engine and heater for engine coolant leaks.

for Fully Sealed Type: Click here 2020 - 2025 MY Corolla Corolla Hatchback [09/2019 -        ]; M20A-FKS (COOLING): COOLING SYSTEM: ON-VEHICLE INSPECTION+

for Non-Fully Sealed Type: Click here 2020 - 2025 MY Corolla Corolla Hatchback [09/2019 -        ]; M20A-FKS (COOLING): COOLING SYSTEM: ON-VEHICLE INSPECTION+

HINT:

If the engine oil is cloudy during the engine oil level gauge check, it means that engine coolant has entered the engine lubrication system.

OK:

No leaks.

NG

GO TO STEP 5

OK

4.

ADD ENGINE COOLANT

(a) Fill the reservoir tank up to the FULL line with engine coolant.

NOTICE:

Make sure not to add engine coolant when the engine is hot.

NEXT

GO TO STEP 6

5.

REPAIR OR REPLACE MALFUNCTIONING PARTS, COMPONENT AND AREA

(a) Repair any engine coolant leaks.

HINT:

Add engine coolant and perform air bleeding after repair.

NEXT

6.

PERFORM ACTIVE TEST USING TECHSTREAM (ACTIVATE THE ELECTRIC WATER PUMP)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine / Active Test / Activate the Electric Water Pump / Data List / Electric Water Pump Speed.

Powertrain > Engine > Active Test

Active Test Display

Activate the Electric Water Pump

Data List Display

Electric Water Pump Speed

(e) According to the display on the Techstream, read the Data List while performing the Active Test.

Standard:

Active Test Operation

Electric Water Pump Speed

3000 rpm

2000 rpm or higher

OK

GO TO STEP 8

NG

7.

INSPECT ECM (INTERNAL CIRCUIT)

*a

Front view of wire harness connector

(to Engine Water Pump Assembly (Water Inlet Housing))

(a) Disconnect the engine water pump assembly (water inlet housing) connector.

(b) Turn the ignition switch to ON.

(c) Measure the resistance according to the value(s) in the table below.

Standard:

Tester Connection

Condition

Specified Condition

C45-2 (SWP) - Body ground

Ignition switch ON

Resistance fluctuates*

HINT:

  • *: When the connector of the engine water pump assembly is disconnected, the ECM will enter fail-safe mode. When the ECM is in fail-safe mode, a continuous duty signal will be output and the resistance will fluctuate as the transistor inside the ECM is turned on an off.
  • If the resistance fluctuates while the ECM is in fail-safe mode after the connector of the engine water pump assembly is disconnected, it can be determined that the transistor is operating.
  • If the transistor is not operating, the ECM may be malfunctioning.
  • If the resistance fluctuates after turning the ignition switch to ON, it can be determined that the ECM is in fail-safe mode.
NG

REPLACE ECM

OK

8.

REPLACE ENGINE WATER PUMP ASSEMBLY (WATER INLET HOUSING)

(a) Replace the engine water pump assembly (water inlet housing).

Click here 2019 - 2023 MY Corolla Corolla Hatchback [06/2018 - 11/2022]; M20A-FKS (COOLING): WATER PUMP (w/o Cooling Fan ECU): REMOVAL

HINT:

When replacing any cooling system parts, if excessive deposits of rust or scale exist or the concentration of the engine coolant is abnormal, replace the engine coolant.

NEXT

9.

CLEAR DTC

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Clear the DTCs.

Powertrain > Engine > Clear DTCs

(e) Turn the ignition switch off and wait for at least 30 seconds.

NEXT

10.

CHECK WHETHER DTC OUTPUT RECURS (DTC P26CB71)

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

(b) Enter the following menus: Powertrain / Engine / Trouble Codes.

(c) Read the DTCs.

Powertrain > Engine > Trouble Codes

HINT:

If no DTC is output, the repair has been successfully completed.

NEXT

END