P059712

DTC Code	DTC Name
P059712	Thermostat Heater Control Circuit Short to Battery

DESCRIPTION

An electric heater is equipped to the temperature sensing portion of the thermostat. During normal driving, current does not flow to the heater and the thermostat functions as an ordinary thermostat. When the temperature of the engine increases by a large amount such as during high-load driving, control is performed to warm the heater of the temperature sensing portion, forcing the valve to open and causing a large amount of coolant to flow from the radiator.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	MIL	Memory	Note
P059712	Thermostat Heater Control Circuit Short to Battery	Short in thermostat heater circuit and power supply circuit (1 trip detection logic).	Short in thermostat heater circuit ECM	Comes on	DTC stored	SAE Code: P0599

Related Data List
DTC No.	Data List
P059712	Coolant Temperature

MONITOR DESCRIPTION

The ECM monitors the output voltage while the thermostat heater is operating.

The thermostat heater turns on and off according to ON/OFF switching of a transistor inside the ECM.

If a continuous mismatch occurs between the ECM transistor state and the output voltage, the ECM determines there is a malfunction in the thermostat heater circuit and stores a DTC.

MONITOR STRATEGY

Frequency of Operation

Continuous

CONFIRMATION DRIVING PATTERN

Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
Turn the engine switch off and wait for at least 30 seconds.
Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher [A].
Turn the GTS on.
Enter the following menus: Powertrain / Engine / Data List / Calculate Load and Coolant Temperature.
Drive the vehicle for at least 3 seconds at the Calculate Load of 45% or more and the Coolant Temperature of 90°C (194°F) or higher [B].

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.
Stop the vehicle.
Enter the following menus: Powertrain / Engine / Trouble Codes [C].
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: P059712.

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 [C] 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 HARNESS AND CONNECTOR (WATER INLET WITH THERMOSTAT SUB-ASSEMBLY - ECM)

Disconnect the water inlet with thermostat sub-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
d6-2 or C57-7 (HTHM) - 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/ Canister Pump Module), Diagnostic DTC:P059712