- Coolant Temperature
- Electric Water Pump Target Speed
- Electric Water Pump Speed
| Last Modified: 05-13-2024 | 6.11:8.1.0 | Doc ID: RM1000000029BON |
| Model Year Start: 2023 | Model: Corolla Hatchback | Prod Date Range: [11/2022 - ] |
| Title: M20A-FKS (ENGINE CONTROL): SFI SYSTEM: P26CB71; Engine Coolant Pump Actuator Stuck; 2023 - 2025 MY Corolla Corolla Hatchback [11/2022 - ] | ||
|
DTC |
P26CB71 |
Engine Coolant Pump Actuator Stuck |
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](/t3Portal/stylegraphics/info.gif)
|
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). |
|
Comes on |
DTC stored |
|
*: 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 |
|
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 |
10.5 V or higher |
|
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 or more |
|
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
-
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 [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: P26CB71.
-
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
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
|
|
|
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
for Non-Fully Sealed Type: Click here
|
Result |
Proceed to |
|---|---|
|
Engine coolant level is above the LOW line |
A |
|
Engine coolant level is below the LOW line |
B |
| A |
|
|
|
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
for Non-Fully Sealed Type: Click here
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 |
|
|
|
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 |
|
|
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.
|
|
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 |
|
|
|
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 |
|---|---|---|
|
C126-3 (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
|
|
|
8. |
REPLACE ENGINE WATER PUMP ASSEMBLY (WATER INLET HOUSING) |
(a) Replace the engine water pump assembly (water inlet housing).
Click here
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.
|
|
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.
|
|
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 |
|
|