Last Modified: 07-31-2024 6.11:8.1.0 Doc ID: RM1000000028LT4
Model Year Start: 2023 Model: Corolla Hatchback Prod Date Range: [11/2022 - 03/2023]
Title: M20A-FKS (ENGINE CONTROL): SFI SYSTEM: P26CA31; Engine Coolant Pump No Signal; 2023 MY Corolla Corolla Hatchback [11/2022 - 03/2023]

DTC

P26CA31

Engine Coolant Pump No Signal

DESCRIPTION

Refer to DTC P26CA12.

Click here 2023 MY Corolla Corolla Hatchback [11/2022 - 03/2023]; 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

P26CA31

Engine Coolant Pump No Signal

The speed of the engine coolant pump calculated from the WPI signal is less than 10 rpm (open or short in the WPI circuit) (1 trip detection logic).
  • Open or short in engine water pump assembly (water inlet housing) circuit
  • Engine water pump assembly (water inlet housing)
  • EFI-MAIN NO. 3 relay
  • ECM

Comes on

DTC stored
  • SAE Code: P26CA
  • DTC for Mexico Models: Applies

Related Data List

DTC No.

Data List

P26CA31
  • 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. 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 the engine water pump assembly speed is calculated to be less than 10 rpm, the ECM judges that there is an open or short in the WPI circuit and stores this DTC.

MONITOR STRATEGY

Related DTCs

P26CA: Engine water pump circuit verify pulse input

Required Sensors/Components (Main)

Engine water pump assembly

Required Sensors/Components (Related)

-

Frequency of Operation

Continuous

Duration

15 seconds

MIL Operation

Immediate

Sequence of Operation

None

TYPICAL ENABLING CONDITIONS

Monitor runs whenever the following DTCs are not stored

None

All of the following conditions are met

-

Battery voltage

8 V or higher

Ignition switch

ON

Time after ignition switch off to ON

0.5 seconds or more

Starter

Off

TYPICAL MALFUNCTION THRESHOLDS

Engine water pump speed

Less than 10 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 2023 - 2025 MY Corolla Corolla Hatchback [11/2022 -        ]; M20A-FKS (ENGINE CONTROL): SFI SYSTEM: DTC CHECK / CLEAR

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

    Click here 2023 - 2025 MY Corolla Corolla Hatchback [11/2022 -        ]; 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 [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: P26CA31.
  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 2023 MY Corolla Corolla Hatchback [11/2022 - 03/2023]; M20A-FKS (ENGINE CONTROL): SFI SYSTEM: P26CA12; Engine Coolant Pump Circuit Short to Battery

CAUTION / NOTICE / HINT

NOTICE:

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

HINT:

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 TERMINAL VOLTAGE (POWER SOURCE OF ENGINE WATER PUMP ASSEMBLY (WATER INLET HOUSING))

*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 voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection

Condition

Specified Condition

C126-2 (NWP) - Body ground

Ignition switch ON

11 to 14 V
NG

GO TO STEP 8

OK

2.

CHECK HARNESS AND CONNECTOR (ENGINE WATER PUMP ASSEMBLY (WATER INLET HOUSING) - BODY GROUND)

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

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

C126-1 (PGND) - Body ground

Always

Below 1 Ω
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

3.

CHECK TERMINAL VOLTAGE (POWER SOURCE OF ENGINE WATER PUMP ASSEMBLY (WATER INLET HOUSING))

*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 voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection

Condition

Specified Condition

C126-4 (+B) - Body ground

Ignition switch ON

11 to 14 V
OK

REPLACE ENGINE WATER PUMP ASSEMBLY (WATER INLET HOUSING)

NG

4.

INSPECT EFI-MAIN NO. 3 RELAY

(a) Inspect the EFI-MAIN NO. 3 relay.

Click here 2023 - 2025 MY Corolla Corolla Hatchback [11/2022 -        ]; M20A-FKS (ENGINE CONTROL): RELAY: ON-VEHICLE INSPECTION+

NG

REPLACE EFI-MAIN NO. 3 RELAY
OK

5.

CHECK HARNESS AND CONNECTOR (POWER SOURCE OF EFI-MAIN NO. 3 RELAY)

*1

No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly

*2

EFI-MAIN NO. 3 Relay

(a) Remove the EFI-MAIN NO. 3 relay from the No. 1 engine room relay block and No. 1 junction block assembly.

(b) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection

Condition

Specified Condition

5 (EFI-MAIN NO. 3 relay) - Body ground

Always

11 to 14 V
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - EFI-MAIN NO. 3 RELAY)
OK

6.

CHECK HARNESS AND CONNECTOR (EFI-MAIN NO. 3 RELAY - BODY GROUND)

(a) Remove the EFI-MAIN NO. 3 relay from the No. 1 engine room relay block and No. 1 junction block assembly.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

2 (EFI-MAIN NO. 3 relay) - Body ground

Always

Below 1 Ω
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

7.

CHECK HARNESS AND CONNECTOR (EFI-MAIN NO. 3 RELAY - ENGINE WATER PUMP ASSEMBLY (WATER INLET HOUSING))

(a) Remove the EFI-MAIN NO. 3 relay from the No. 1 engine room relay block and No. 1 junction block assembly.

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

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

3 (EFI-MAIN NO. 3 relay) - C126-4 (+B)

Always

Below 1 Ω

3 (EFI-MAIN NO. 3 relay) or C126-4 (+B) - Body ground and other terminals

Always

10 kΩ or higher
OK

REPAIR OR REPLACE HARNESS OR CONNECTOR (EFI-MAIN NO. 1 RELAY - EFI-MAIN NO. 3 RELAY)
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

8.

CHECK HARNESS AND CONNECTOR (ENGINE WATER PUMP ASSEMBLY (WATER INLET HOUSING) - ECM)

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

(b) Disconnect the ECM connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

C126-2 (NWP) - C76-51 (WPI)

Always

Below 1 Ω

C126-2 (NWP) or C76-51 (WPI) - Body ground and other terminals

Always

10 kΩ or higher
OK

REPLACE ECM

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR