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). |
| Comes on | DTC stored | SAE Code: P0599 |
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
Related DTCs | P0599: Thermostat heater range check (high voltage) |
Required Sensors/Components (Main) | Thermostat heater |
Required Sensors/Components (Related) | - |
Frequency of Operation | Continuous |
Duration | 3 seconds |
MIL Operation | Immediate |
Sequence of Operation | None |
TYPICAL ENABLING CONDITIONS
Monitor runs whenever the following DTCs are not stored | None |
All of the following conditions are met | - |
Either of the following conditions is met | 1 or 2 |
1. Both of the following conditions are met | (a) and (b) |
(a) Last thermostat heater output terminal voltage level | Low |
(b) Current thermostat heater output terminal voltage level | Low |
2. Both of the following conditions are met | (c) and (d) |
(c) Last thermostat heater output terminal voltage level | High |
(d) Current thermostat heater output terminal voltage level | High |
Auxiliary battery voltage | 8 V or higher |
Command to thermostat heater | On |
TYPICAL MALFUNCTION THRESHOLDS
Thermostat heater output terminal voltage level | High |
CONFIRMATION DRIVING PATTERN
HINT:
Click here
Click here
Click here
CAUTION:
When performing the confirmation driving pattern, obey all speed limits and traffic laws.
HINT:
If the engine stops, further depress the accelerator pedal to restart the engine.
HINT:
Techstream Display | Description |
---|---|
NORMAL |
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ABNORMAL |
|
INCOMPLETE |
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HINT:
The normal judgment procedure is used to complete DTC judgment and also used when clearing permanent DTCs.
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
Click here
(Select Powertrain in Health Check and then check the time stamp data.)
Click here
Click here
HINT:
Read Freeze Frame Data using the Techstream. 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 HARNESS AND CONNECTOR (THERMOSTAT HEATER - ECM) |
(a) Disconnect the water inlet with thermostat sub-assembly 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 |
---|---|---|
F5-2 (ETM-) or C88-7 (HTHM) - other terminals | Always | 10 kΩ or higher |
OK | REPLACE ECM |
NG | REPAIR OR REPLACE HARNESS OR CONNECTOR |