Engine Hybrid System. Corolla. Zre142 Aze141
2Zr-Fe Engine Control. Corolla. Zre142 Aze141
TYPICAL MALFUNCTION THRESHOLDS
CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0128)
DTC P0128 Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature) |
DESCRIPTION
- HINT:
- This DTC relates to the thermostat.
| DTC No. | DTC Detection Condition | Trouble Area |
| P0128 |
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MONITOR DESCRIPTION
The 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 sets the DTC.
MONITOR STRATEGY
| Related DTCs | P0128: Coolant Thermostat |
| Required Sensors/Components (Main) | Thermostat Engine coolant temperature sensor |
| Required Sensors/Components (Related) | Intake air temperature sensor Vehicle speed sensor |
| Frequency of Operation | Once per driving cycle |
| Duration | 550 seconds |
| MIL Operation | 2 driving cycles |
| Sequence of Operation | None |
TYPICAL ENABLING CONDITIONS
| Monitor runs whenever following DTCs not present | P0010 (VVT Oil Control Valve) P0011 (VVT System - Advance) P0012 (VVT System - Retard) P0013 (Exhaust VVT Oil Control Valve) P0014 (Exhaust VVT System - Advance) P0015 (Exhaust VVT System - Retard) P0016 (VVT System - Misalignment) P0017 (Exhaust VVT System - Misalignment) P0031, P0032 (Air Fuel Ratio Sensor Heater - Sensor 1) P0102, P0103 (Mass Air Flow Meter) P0112, P0113 (Intake Air Temperature Sensor) P0115, P0117, P0118 (Engine Coolant Temperature Sensor) P0120, P0121 P0122, P0123, P0220, P0222, P0223, P2135 (Throttle Position Sensor) P0171, P0172 (Fuel System) P0301, P0302, P0303, P0304 (Misfire) P0335 (Crankshaft Position Sensor) P0340, P0342, P0343 (Camshaft Position Sensor) P0351, P0352, P0353, P0354 (Igniter) P0365, P0367, P0368 (Exhaust Camshaft Position Sensor) P0500 (Vehicle Speed Sensor) P2195, P2196, P2237, P2238, P2239, P2252, P2253, P2A00 (Air Fuel Ratio Sensor - Sensor 1) P219A (Air Fuel Ratio Imbalance) |
| Battery voltage | 11 V or more |
| Either of following conditions 1 or 2 is met: | - |
| 1. All of following conditions are met: | - |
| -15 to 7°C (-27 to 12.6°F) |
| -10 to 56°C (14 to 133°F) |
| -10 to 56°C (14 to 133°F) |
| 2. All of following conditions are met: | - |
| More than 7°C (12.6°F) |
| 56°C (133°F) or less |
| -10°C (14°F) or more |
| Accumulated time at 80 mph (128 km/h) or more of vehicle speed | Less than 20 seconds |
TYPICAL MALFUNCTION THRESHOLDS
| Duration that both of following conditions (a) and (b) are met | 5 seconds or more |
| (a) Estimated engine coolant temperature | 75°C (167°F) or more |
| (b) Engine coolant temperature sensor output | Below 75°C (167°F) |
CONFIRMATION DRIVING PATTERN
- Stop the engine and allow it to soak.
- Connect the Techstream to the DLC3.
- Turn the ignition switch to ON and turn the Techstream on [A].
- Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Coolant Temp and Intake Air.
- Check that "Coolant Temp" is 56°C (133°F) or less and "Intake Air" is between 0 and 35°C (32 and 95°F).
- Set the heater to MAX HOT with fresh air mode selected and turn the A/C off.
- Start the engine and drive the vehicle at 50 mph (80 km/h) for 15 minutes [B].
- CAUTION:
- When performing the confirmation driving pattern, obey all speed limits and traffic laws.
- HINT:
- Data can be captured relatively easily by using the snapshot function in the Data List.
- Enter the following menus: Data List / Function / Snapshot Configure / Duration / 5 min.
- Data capture can be started by using the target point function. For example, setting the target point to an engine speed of 4000 rpm and then racing the engine, etc. to raise the engine speed to a speed of 4000 rpm or more will cause data capture to start.
- After "Coolant Temp" stabilizes, check that "Coolant Temp" is 75°C (167°F) or higher [C].
- HINT:
- If "Coolant Temp" is below 75°C (167°F) while driving the vehicle at 50 mph (80 km/h), inspect the cooling system and thermostat.
INSPECTION PROCEDURE
- 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 be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.
- When the DTC is output, check the engine coolant temperature using the Techstream. Enter the following menus: Powertrain / Engine and ECT / Data List / Primary / Coolant Temp. If the Coolant Temp value is lower than the actual engine coolant temperature, the engine coolant temperature sensor circuit may be malfunctioning. In this case, check the wire harnesses and connectors (and those connections) between the ECM and the engine coolant temperature sensor first.
| 1.CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0128) |
Connect the Techstream to the DLC3.
Turn the ignition switch to ON.
Turn the Techstream on.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
Read the DTCs.
- Result:
Result Proceed to DTC P0128 is output A DTC P0128 and other DTCs are output B
- HINT:
- If any DTCs other than P0128 are output, troubleshoot those DTCs first.
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| A | |
| 2.CHECK COOLING SYSTEM |
Check for defects in the cooling system that might cause the system to be too cold, such as abnormal radiator fan operation or any modifications.
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| OK | |
| 3.INSPECT THERMOSTAT |
Inspect the thermostat (thermostat opening temperature) (COROLLA_ZRE142 RM00000335X02JX.html).
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| OK | ||
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