M20C-FKS 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 (water inlet housing) circuit ·
Engine water pump assembly (water inlet housing) ·
ECM |
Comes on | DTC stored | SAE: 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.
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: 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 [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
- 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
| *a | Front view of wire harness connector
(to Engine Water Pump Assembly (Water Inlet Housing)) |
Disconnect the engine water pump assembly (water inlet housing) connector.
Turn the ignition switch to ON.
Measure the voltage according to the value(s) in the table below.
- Standard Voltage:
Tester Connection Switch Condition Specified Condition C74-3 (SWP) - Body ground Ignition Switch ON Below 1 V
- Result:
Proceed to OK NG
OK
NG
| *a | Front view of wire harness connector
(to Engine Water Pump Assembly (Water Inlet Housing)) |
Disconnect the engine water pump assembly (water inlet housing) connector.
Connect the GTS to the DLC3.
Turn the ignition switch to ON.
Turn the GTS on.
Enter the following menus: Powertrain / Engine / Active Test / Activate the Electric Water Pump.
- Powertrain > Engine > Active Test
-
Tester Display Activate the Electric Water Pump - 50004 372 42
Operate the engine water pump assembly (water inlet housing) using the Active Test function and measure the resistance according to the value(s) in the table below.
- Standard:
Tester Connection GTS Operation Specified Condition C74-3 (SWP) - Body ground 3000 rpm 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 (water inlet housing) connector.
Disconnect the ECM connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
Tester Connection Condition Specified Condition C74-3 (SWP) or C71-103 (WPO) - Other terminals Always 10 kΩ or higher
- Result:
Proceed to OK NG
OK
NG