The OBD code P0128 for Hyundai indicates a thermostat regulating the engine temperature is not functioning properly.
This affects the engine coolant system.
Symptoms include the Engine Light being ON.
Causes may include a faulty thermostat, low coolant level, or a defective coolant temperature sensor.
It’s a moderate issue that can affect engine performance.
A possible fix is to inspect and replace any faulty components in the coolant system.
| Repair Importance Level | 10.0 (Out of 10) |
| Estimated Repair Time | Approximately 1.0 hour |
| Repair Difficulty Level | 6.67 (Out of 10) |
Symptoms of the Hyundai p0128 OBD Code
The vehicle may exhibit a low coolant temperature condition indicated by Hyundai P0128 fault code.
- Symptoms for Hyundai OBD code P0128: Engine Light ON (or Service Engine Soon Warning Light).
- The engine may take longer to reach operating temperature.
- Reduced fuel efficiency.
- The heater may not produce enough heat inside the vehicle.
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Causes of the Hyundai p0128 OBD Code
P0128 in a Hyundai typically indicates a thermostat stuck open or a faulty coolant temperature sensor.
- P0128 can be caused by a leaking or stuck open thermostat.
- Low engine coolant level.
- Insufficient warm up time.
- A faulty engine coolant temperature sensor.
- An engine coolant temperature sensor harness that is open or shorted.
- Or an engine coolant temperature sensor circuit with a poor electrical connection.
Fixing Hyundai Error Code p0128 Step By Step
Addressing fault code P0128 on a Hyundai involves diagnosing and resolving issues with the coolant thermostat.
- To fix Hyundai OBDII code P0128, review the ‘Possible Causes’ mentioned above and visually examine the corresponding wiring harness and connectors.
- Ensure to check for any damaged components and inspect the connector pins for signs of being broken, bent, pushed out, or corroded.
- Test the operation of the thermostat to ensure it is functioning correctly.
- Replace the thermostat if it is stuck open or not reaching operating temperature.
- Clear the fault code using a scan tool after completing the repair.
- Drive the vehicle to verify the code does not return, indicating a successful repair.
Cost Of Fixing Hyundai p0128 Fault Code
The repair for Hyundai P0128 typically involves replacing the thermostat to address the cooling system issue.
The cost to diagnose and fix the Hyundai OBD code P0128 depends on the estimated 1. 0hour repair time.
Labor rates usually range from $75 to $150 per hour, so the total cost could be between $75 and $150, depending on shop rates and the complexity of the repair.
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Details of the Hyundai p0128 OBD Code
Hyundai P0128 indicates a thermostat malfunction causing the engine to run cooler than normal.
OBD code P0128 for Hyundai vehicles indicates that the engine coolant temperature is below the thermostat regulating temperature.
This code is triggered by the Engine Control Module (ECM) when it detects that the coolant temperature does not reach the expected level within a specified time after starting the engine.
The P0128 code is related to the engine coolant thermostat and the engine coolant temperature sensor.
The thermostat is responsible for regulating the engine temperature by controlling the flow of coolant through the engine.
The engine coolant temperature sensor provides the ECM with data on the actual temperature of the coolant.
When the ECM detects that the engine coolant temperature is not reaching the expected level within the specified time frame, it triggers the P0128 trouble code, indicating a potential issue with the thermostat or the engine coolant temperature sensor.
This code is important as it helps in maintaining the engine at the optimal operating temperature for performance and emissions control.
Mechanic’s Tech Notes
For Hyundai P0128, monitor coolant temperature sensor for possible issues causing low engine temperature.
To diagnose and fix OBDII code P0128 on a Hyundai, start by checking the thermostat operation and coolant level.
Use a scan tool to monitor coolant temperature sensor data while the engine warms up.
If the temperature doesn’t rise steadily or stays below the specified range, the thermostat or sensor may be faulty.
Additionally, inspect the wiring harness and connectors for any damage or corrosion.
Test the coolant temperature sensor resistance with a multimeter to ensure it’s within specifications.
If all checks out, consider replacing the thermostat or sensor as needed.
FAQ
Common causes of OBD code P0128 in a Hyundai: leaking or stuck open thermostat, low coolant level, faulty coolant temperature sensor, poor electrical connection.
Diagnose P0128 in Hyundai: Check thermostat, coolant level, warmup time, sensor, harness. Inspect wiring for damage, connector pins for issues. Fix as needed.
It is not safe to continue driving with OBD code P0128 in a Hyundai. Check for thermostat issues, low coolant, or faulty sensors. Inspect wiring and connectors for damage.
Wrap Up
If your Hyundai triggers OBD code P0128 and you notice the temperature gauge not reaching operating temperature, it could be caused by a faulty thermostat, low coolant level, or a malfunctioning engine coolant temperature sensor.
To address Hyundai OBD code P0128, check the thermostat operation, inspect the coolant level, and test the engine coolant temperature sensor.
Ensure the wiring harness and connectors related to these components are in good condition to prevent false readings.
