8ZR-FXE ENGINE CONTROL SFI SYSTEM P26CA12 Engine Coolant Pump Circuit Short to Battery
DESCRIPTION
The ECM calculates the necessary cooling amount based on the engine coolant temperature, engine speed and vehicle speed, and controls the engine water pump assembly accordingly. The engine water pump assembly controls the speed of the engine water pump assembly steplessly and optimally based on a duty cycle signal sent by the ECM, which reduces engine warm-up time, improves fuel efficiency and reduces cooling loss.
| DTC No. | Detection Item | DTC Detection Condition | Trouble Area | MIL | Memory | Note |
|---|---|---|---|---|---|---|
| P26CA12 | Engine Coolant Pump Circuit Short to Battery | The operation duty ratio signal (WPO) of the engine water pump assembly is a certain value or more when the engine water pump assembly operation signal is being output (1 trip detection logic). | ·
Short in engine water pump assembly circuit ·
Engine water pump assembly ·
ECM |
Comes on | DTC stored | SAE Code: P26CD |
| DTC No. | Data List |
|---|---|
| P26CA12 | ·
Coolant Temperature ·
Electric Water Pump Target Speed ·
Electric Water Pump Speed |
MONITOR DESCRIPTION
The ECM outputs an operation duty signal (WPO) to steplessly control the speed of the engine water pump assembly. The ECM outputs an operation duty signal (WPO) to the engine water pump assembly and monitors the actual duty signal (WPO) being output. When the actual operation duty signal (WPO) exceeds a certain value when outputting an operation duty signal (WPO) to the engine water pump assembly, the ECM detects a malfunction and stores a DTC.
MONITOR STRATEGY
| Required Sensors/Components | Engine water pump assembly |
| Frequency of Operation | Continuous |
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.
·When clearing the permanent DTCs, refer to the "CLEAR PERMANENT DTC" procedure.
Connect the GTS to the DLC3.
Turn the ignition switch to ON.
Turn the GTS 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 GTS on.
Put the engine in Inspection Mode (Maintenance Mode).
Start the engine and maintain the engine speed at 2500 rpm or more for at least 40 seconds [B].
Enter the following menus: Powertrain / Engine / Trouble Codes [C].
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: P26CA12.
Check the DTC judgment result.
| GTS 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 [C] again.
·[A] to [C]: 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 auxiliary 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
- NOTICE:
- ·
Vehicle Control History may be stored in the hybrid vehicle control ECU if the engine is malfunctioning. Certain vehicle condition information is recorded when Vehicle Control History is stored. Reading the vehicle conditions recorded in both the freeze frame data and Vehicle Control History can be useful for troubleshooting.
(Select Powertrain in Health Check and then check the time stamp data.)
·If any "Engine Malfunction" Vehicle Control History item has been stored in the hybrid vehicle control ECU, make sure to clear it. However, as all Vehicle Control History items are cleared simultaneously, if any Vehicle Control History items other than "Engine Malfunction" are stored, make sure to perform any troubleshooting for them before clearing Vehicle Control History.
- HINT:
-
Read Freeze Frame Data using the GTS. 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
Disconnect the engine water pump assembly connector.
Turn the ignition switch to ON.
Measure the voltage according to the value(s) in the table below.
- Standard Voltage:
Tester Connection Condition Specified Condition C124-3 (SWP) - Body ground Ignition switch ON Below 1 V
- Result:
Proceed to OK NG
OK
NG
Disconnect the engine water pump assembly connector.
Perform the Active Test using the GTS.
- Powertrain > Engine > Active Test
-
Tester Display Activate the Electric Water Pump - 50004 372 42 437
Measure the resistance according to the value(s) in the table below.
- Standard:
Tester Connection Condition Specified Condition C124-3 (SWP) - Body ground During Active Test Resistance fluctuates*
- HINT:
-
*: Using the Active Test, duty control of the transistors in the ECM will be performed. Due to the duty control, resistance of the SWP terminal will be unstable during the Active Test. If the resistance fluctuates while performing the Active Test, it can be determined that the transistor is operating. If the transistor does not operate during the Active Test, the ECM may be malfunctioning.
- Result:
Proceed to OK NG
OK
NG
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 C124-3 (SWP) or C155-71 (WPO) - Other terminals Always 10 kΩ or higher
- Result:
Proceed to OK NG
OK
NG