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 | 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). |
| Comes on |
|
DTC No. | Data List |
---|---|
P26CA12 |
|
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
Related DTCs | P26CD: Engine water pump circuit range check (High voltage) |
Required Sensors/Components (Main) | Engine water pump assembly |
Required Sensors/Components (Related) |
- |
Frequency of Operation |
Continuous |
Duration |
3 seconds |
MIL Operation |
Immediate |
Sequence of Operation |
None |
TYPICAL ENABLING CONDITIONS
All of the following conditions are met |
- |
Auxiliary battery voltage |
8 V or higher |
Ignition switch | ON |
Time after ignition switch off to ON |
0.5 seconds or more |
Output duty cycle | 30 to 85% |
Starter | Off |
Engine water pump circuit pulse input fail (P26CA) (Pending / MIL) |
Not detected |
TYPICAL MALFUNCTION THRESHOLDS
Both of the following conditions are met |
- |
Engine water pump assembly output terminal voltage level |
High |
Engine water pump assembly output signal |
No signal |
CONFIRMATION DRIVING PATTERN
HINT:
Click here
Click here
HINT:
GTS Display |
Description |
---|---|
NORMAL |
|
ABNORMAL |
|
INCOMPLETE |
|
HINT:
The normal judgment procedure is used to complete DTC judgment and also used when clearing permanent DTCs.
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
1. |
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)) |
(a) Disconnect the engine water pump assembly (water inlet housing) connector.
(b) Turn the ignition switch to ON.
(c) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
Tester Connection | Condition |
Specified Condition |
---|---|---|
C131-3 (SWP) - Body ground |
Ignition switch ON | Below 1 V |
NG | GO TO STEP 3 |
|
2. |
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 |
---|---|---|
C131-3 (SWP) - Body ground |
Ignition switch ON | Resistance fluctuates* |
HINT:
OK | REPLACE ENGINE WATER PUMP ASSEMBLY (WATER INLET HOUSING) |
NG | REPLACE ECM |
3. |
CHECK HARNESS AND CONNECTOR (ENGINE WATER PUMP ASSEMBLY (WATER INLET HOUSING) - ECM) |
(a) Disconnect the engine water pump assembly (water inlet housing) connector.
(b) Disconnect the ECM connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection | Condition |
Specified Condition |
---|---|---|
C131-3 (SWP) or C76-50 (WPO) - Other terminals |
Always | 10 kΩ or higher |
OK | REPLACE ECM |
NG | REPAIR OR REPLACE HARNESS OR CONNECTOR |