P26CA12

DTC Code	DTC Name
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 Code: P26CD

Related Data List
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

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.
Tech Tips
- 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

Tech Tips

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.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

Tech Tips

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

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))

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	Condition	Specified Condition
C43-2 (SWP) - Body ground	Ignition switch ON	Below 1 V

Result

Proceed to
OK
NG

NG

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

OK

INSPECT ECM (INTERNAL CIRCUIT)

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

Standard

Tester Connection	Condition	Specified Condition
C43-2 (SWP) - Body ground	Ignition switch ON	Resistance fluctuates*

Tech Tips

*: When the connector of the engine water pump assembly is disconnected, the ECM will enter fail-safe mode. In this case, duty control of the transistors in the ECM will be performed and resistance fluctuates.
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 does not operate, the ECM may be malfunctioning.
If the resistance fluctuates after turning the ignition switch ON, it can be determined that the ECM is in fail-safe mode.

Result

Proceed to
OK
NG

OK

REPLACE ENGINE WATER PUMP ASSEMBLY (WATER INLET HOUSING) Click here

NG

REPLACE ECM Click here

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

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
C43-2 (SWP) or C57-50 (WPO) - Other terminals	Always	10 kΩ or higher

Result

Proceed to
OK
NG

OK

REPLACE ECM Click here

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

SFI SYSTEM(w/o Canister Pump Module), Diagnostic DTC:P26CA12