M20A-FKS (ENGINE CONTROL): SFI SYSTEM: P26CA31; Engine Coolant Pump No Signal; 2023 MY Corolla Corolla Hatchback [09/2022

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

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

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

Connect the Techstream to the DLC3.
Turn the ignition switch to ON.
Turn the Techstream on.
Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
Turn the ignition switch off and wait for at least 30 seconds.
Turn the ignition switch to ON [A].
Turn the Techstream on.
Move the shift lever to P or neutral [B].
Start the engine and maintain the engine speed at 2500 rpm or more for at least 40 seconds [C].
Enter the following menus: Powertrain / Engine / Trouble Codes [D].
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.
Enter the following menus: Powertrain / Engine / Utility / All Readiness.
Input the DTC: P26CA31.

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

CAUTION / NOTICE / HINT

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

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

for TMMMS Made

for TMC Made

for TMMMS Made

for TMC Made

for TMMMS Made

for TMC Made

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

DESCRIPTION

Related Data List

MONITOR DESCRIPTION

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

CONFIRMATION DRIVING PATTERN

WIRING DIAGRAM

CAUTION / NOTICE / HINT

PROCEDURE

for TMMMS Made

for TMC Made

for TMMMS Made

for TMC Made

for TMMMS Made

for TMC Made