DESCRIPTION
The ECM uses the engine coolant temperature sensor, installed to the water outlet, to monitor the operation of the thermostat.
DTC No. | Detection Item |
DTC Detection Condition | Trouble Area |
MIL | Note |
---|---|---|---|---|---|
P012800 | Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature) |
All of the following conditions are met for 5 seconds or more (2 trip detection logic):
|
| Comes on |
|
P012807 |
Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature) Mechanical Failure |
All of the following conditions are met for 3 times (2 trip detection logic):
|
| Comes on |
|
MONITOR DESCRIPTION
P012800: Judgment by Simulated Engine Coolant TemperatureThe ECM estimates the engine coolant temperature based on the starting temperature, engine loads, and engine speeds. The ECM then compares the estimated temperature with the actual engine coolant temperature. When the estimated engine coolant temperature reaches 75°C (167°F), the ECM checks the actual engine coolant temperature. If the actual engine coolant temperature is less than 75°C (167°F), the ECM interprets this as a malfunction in the thermostat or the engine cooling system and stores the DTC.
P012807: Judgment by Engine Coolant Temperature Change at High Vehicle SpeedWhen the vehicle is being driven between 65 and 128 km/h (40.625 and 80 mph) and the monitoring conditions are met, the change in engine coolant temperature is monitored. The amount of change is judged to be normal or abnormal every 15 seconds, in order to monitor the thermostat operation. If the engine coolant temperature changes more than the threshold, the thermostat is judged as normal, but if it changes less than the threshold, the thermostat is judged to be malfunctioning. If an abnormal judgment is made 3 times, the ECM will illuminate the MIL and store a DTC.
MONITOR STRATEGY
Related DTCs | P0128: Coolant thermostat (judgment by simulated engine coolant temperature) P0128: Coolant thermostat (judgment by engine coolant temperature change at high vehicle speed) |
Required Sensors/Components (Main) | Thermostat Engine coolant temperature sensor |
Required Sensors/Components (Related) |
Intake air temperature sensor (for mass air flow meter sub-assembly) Vehicle speed sensor |
Frequency of Operation |
Once per driving cycle: Judgment by simulated engine coolant temperature Continuous: Judgment by engine coolant temperature change at high vehicle speed |
Duration | 300 seconds: Judgment by simulated engine coolant temperature -: Judgment by engine coolant temperature change at high vehicle speed |
MIL Operation | 2 driving cycles |
Sequence of Operation | None |
TYPICAL ENABLING CONDITIONS
ALL
Monitor runs whenever the following DTCs are not stored |
P0010, P0020 (VVT oil control solenoid bank 1, 2) P0011, P0021 (VVT system bank 1, 2 - advance) P0012, P0022 (VVT system bank 1, 2 - retard) P0013, P0023 (Exhaust VVT oil control solenoid bank 1, 2) P0014, P0024 (Exhaust VVT system bank 1, 2 - advance) P0015, P0025 (Exhaust VVT system bank 1, 2 - retard) P0016, P0018 (VVT system bank 1, 2 - misalignment) P0017, P0019 (Exhaust VVT system bank 1, 2 - misalignment) P0031, P0032, P0051, P0052, P101D, P103D (Air fuel ratio sensor heater) P0087, P0088, P0191, P0192, P0193 (Fuel pressure sensor (for high pressure side)) P0101, P0102, P0103 (Mass air flow meter) P0111, P0112, P0113 (Intake air temperature sensor) P0116, P0117, P0118 (Engine coolant temperature sensor) P011B (Engine coolant temperature/intake air temperature sensor correlation) P0121, P0122, P0123, P0222, P0223, P2135 (Throttle position sensor) P014C, P014D, P014E, P014F, P015A, P015B, P015C, P015D, P2195, P2196, P2197, P2198, P2237, P2238, P2239, P2240, P2241, P2242, P2252, P2253, P2255, P2256 (Air fuel ratio sensor) P0171, P0172, P0174, P0175 (Fuel system) P0201, P0202, P0203, P0204, P0205, P0206, P062D, P21CF, P21D0, P21D1, P21D2, P21D3, P21D4 (Fuel injector) P0300 - P0306 (Misfire) P0335, P0337, P0338 (Crankshaft position sensor) P0340, P0342, P0343, P0345, P0347, P0348 (Camshaft position sensor) P0365, P0367, P0368, P0390, P0392, P0393 (Exhaust camshaft position sensor) P0351 - P0356 (Igniter) P0500 (Vehicle speed sensor) P107B, P107C, P107D (Fuel pressure sensor (for low pressure side)) P11EA, P11EB, P11EC, P11ED, P11EE, P11EF, P11F0, P11F1, P219A, P219B P219C, P219D, P219E, P219F, P21A0, P21A1 (Air-fuel ratio imbalance) P1235 (High pressure fuel pump circuit) |
Auxiliary battery voltage | 11 V or higher |
Either of the following conditions is met |
1 or 2 |
1. All of the following conditions are met |
(a), (b) and (c) |
(a) Engine coolant temperature at engine start - Intake air temperature (for mass air flow meter sub-assembly) at engine start |
-15 to 7°C (5 to 45°F) |
(b) Engine coolant temperature at engine start |
-10 to 56°C (14 to 133°F) |
(c) Intake air temperature (for mass air flow meter sub-assembly) at engine start |
-10 to 56°C (14 to 133°F) |
2. All of the following conditions are met |
(d), (e) and (f) |
(d) Engine coolant temperature at engine start - Intake air temperature (for mass air flow meter sub-assembly) at engine start |
Higher than 7°C (45°F) |
(e) Engine coolant temperature at engine start |
56°C (133°F) or less |
(f) Intake air temperature (for mass air flow meter sub-assembly) at engine start |
-10°C (14°F) or higher |
Accumulated time at vehicle speed of 128 km/h (80 mph) or more |
Less than 20 seconds |
During that all of the following conditions are met |
15 seconds or more |
Auxiliary battery voltage |
11 V or higher |
Engine coolant temperature at engine start |
-10°C (14°F) or higher |
Intake air temperature at engine start |
-10°C (14°F) or higher |
Target engine coolant flow by electric water pump |
1.5 L/min or more |
Vehicle speed |
65 to 128 km/h (40.625 to 80 mph) |
TYPICAL MALFUNCTION THRESHOLDS
P012800: Judgment by Simulated Engine Coolant Temperature
Duration that both of the following conditions are met |
5 seconds or more |
(a) Estimated engine coolant temperature |
75°C (167°F) or higher |
(b) Engine coolant temperature sensor output |
Less than 75°C (167°F) |
Malfunction counter | 3 times or more |
Malfunction counter is incremented when following conditions are met |
A and B |
A. Average engine coolant temperature change (vary with current engine coolant temperature, estimated ambient air temperature, intake air mass and vehicle speed) |
Less than -0.02°C/sec (-0.07°F/sec) |
B. Engine coolant temperature is satisfied throughout this period |
Less than 75°C (167°F) |
CONFIRMATION DRIVING PATTERN
HINT:
Click here
Click here
Click here INTRODUCTION > REPAIR INSTRUCTION > INSPECTION MODE PROCEDURE
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:
If the value of the Data List item Coolant Temperature is less than 75°C (167°F) while driving the vehicle at 80 km/h (50 mph), inspect the cooling system and thermostat.
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.
Click here INTRODUCTION > REPAIR INSTRUCTION > INSPECTION MODE PROCEDURE
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:
GTS Display |
Description |
---|---|
NORMAL |
|
ABNORMAL |
|
INCOMPLETE |
|
HINT:
The normal judgment procedure is used to complete DTC judgment and also used when clearing permanent DTCs.
CAUTION / NOTICE / HINT
NOTICE:
Click here
(Select Powertrain in Health Check and then check the time stamp data.)
Click here
Click here
HINT:
PROCEDURE
1. | CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P012800 OR P012807) |
(a) Read the DTCs.
Powertrain > Engine > Trouble Codes
Result | Proceed to |
---|---|
DTC P012800 or P012807 is output |
A |
DTC P012800 or P012807 and other DTCs are output |
B |
HINT:
If any DTCs other than P012800 or P012807 are output, troubleshoot those DTCs first.
B | GO TO DTC CHART |
|
2. |
CHECK ENGINE COOLING SYSTEM |
(a) Check for defects in the engine cooling system that might cause the system to be too cold, such as abnormal cooling fan operation or any modifications.
NG | REPAIR OR REPLACE ENGINE COOLING SYSTEM |
|
3. |
INSPECT WATER INLET WITH THERMOSTAT SUB-ASSEMBLY |
(a) Inspect the water inlet with thermostat sub-assembly (thermostat opening temperature).
Click here
NG | REPLACE WATER INLET WITH THERMOSTAT SUB-ASSEMBLY |
|
4. |
INSPECT ENGINE COOLANT TEMPERATURE SENSOR |
(a) Inspect the engine coolant temperature sensor.
Click here
HINT:
Perform "Inspection After Repair" after replacing the engine coolant temperature sensor.
Click here
OK | REPLACE ECM |
NG | REPLACE ENGINE COOLANT TEMPERATURE SENSOR |