P1198 Radiator Temperature Sensor Voltage Too High

The P1198 Radiator Temperature Sensor Voltage Too High code indicates that the voltage of the radiator temperature sensor is too high.

This could be due to a malfunctioning or faulty radiator temperature sensor, an electrical issue such as a wiring fault, or even low coolant levels in the cooling system.

The radiator temperature sensor measures the coolant temperature in order to determine how much fuel is being used by the engine.

If there is an issue with the voltage coming from this sensor, then it can lead to excessive fuel consumption or even misfires within the engine itself.

Additionally, if left unresolved for a long period of time, this problem could cause serious damage to other parts like spark plugs or oxygen sensors due to extreme temperatures.

In this article, we’ll delve into the intricacies of the P1198 error, its causes, implications, and most importantly, the steps you can take to troubleshoot and fix it.

Understanding the P1198 Error Code

P1198 Radiator Temperature Sensor Voltage Too High

The P1198 error code is a diagnostic trouble code (DTC) that indicates a problem related to the radiator temperature sensor’s voltage reading.

This sensor plays a crucial role in regulating your engine’s temperature and ensuring optimal performance. Essentially, it provides the engine control module (ECM) with information about the coolant temperature, enabling the ECM to adjust fuel mixture, ignition timing, and other factors that affect engine operation.

When the voltage from the radiator temperature sensor is deemed too high by the ECM, it triggers the P1198 error code. This high voltage reading can be the result of several underlying issues, which we’ll explore next.

Causes of the P1198 Radiator Temperature Sensor Voltage Too High Error

  • Faulty Radiator Temperature Sensor: Just like any electronic component, the sensor itself can fail. This might be due to manufacturing defects, wear and tear, or exposure to extreme temperatures.
  • Wiring and Connector Issues: The sensor’s readings are transmitted to the ECM through wiring and connectors. Damaged or corroded wiring can lead to voltage abnormalities, causing the ECM to detect an error.
  • Engine Overheating: If your engine is running too hot, the sensor might pick up inaccurate readings, causing the ECM to think the voltage is too high.
  • Issues with the Engine Control Module: Problems within the ECM itself can lead to misinterpretation of sensor data, resulting in the erroneous error code.

Implications of Ignoring the P1198 Error Code

P1198 Radiator Temperature Sensor Voltage Too High

Ignoring the P1198 error can have a cascade of negative effects on your vehicle. Firstly, engine performance and efficiency can be compromised.

The ECM relies on accurate sensor data to make real-time adjustments for optimal combustion, and an incorrect reading can lead to suboptimal power delivery and decreased fuel efficiency.

Additionally, prolonged ignorance of this error can put your engine at risk of damage. Engines are designed to operate within specific temperature ranges, and if the cooling system isn’t functioning correctly due to the sensor error, overheating can occur.

Overheating can cause warped cylinder heads, blown head gaskets, and other severe issues that are not only expensive to fix but can also render your vehicle inoperable.

Moreover, unresolved temperature sensor issues can contribute to increased emissions, harming the environment and possibly leading to legal compliance issues in regions with strict emissions standards.

Read More About: P1281 Engine Operating Temp Below Acceptable Range

Diagnosing the P1198 Error Code

Diagnosing the P1198 error code requires a systematic approach to pinpoint the underlying issue accurately. This code, indicating a “Radiator Temperature Sensor Voltage Too High” problem, can affect your vehicle’s engine performance and cooling system.

Here’s a detailed guide on how to diagnose the P1198 error:

Using an OBD-II Scanner

  • Connect the Scanner: Plug an OBD-II scanner into the vehicle’s diagnostic port, usually located under the dashboard near the driver’s seat.
  • Retrieve Error Code: Turn the ignition on (engine off) and follow the scanner’s prompts to retrieve the error codes. Look for the specific code P1198.
  • Record Freeze Frame Data: The scanner may provide freeze frame data, which includes information about engine conditions when the error occurred. Note the engine temperature, vehicle speed, and other relevant data.

Visual Inspection

  • Inspect the Radiator Temperature Sensor: Locate the radiator temperature sensor, often situated near the radiator or on the engine block. Visually inspect the sensor, wires, and connectors for any visible damage, corrosion, or loose connections.
  • Check Wiring: Trace the wiring from the sensor to the ECM. Inspect the wiring harness for any signs of fraying, damage, or exposed wires.
  • Examine Connectors: Ensure that connectors are securely plugged in and not corroded. Corrosion can lead to poor connections and inaccurate readings.

Testing the Sensor

  • Multimeter Setup: Prepare a digital multimeter to measure resistance and voltage. Set the multimeter to the appropriate settings.
  • Resistance Test: Disconnect the sensor’s electrical connector. Place the multimeter probes on the sensor’s terminals. Compare the resistance reading to the manufacturer’s specifications. Abnormal resistance values might indicate a faulty sensor.
  • Voltage Test: Reconnect the electrical connector to the sensor. Insert the multimeter probes into the connector to measure voltage. Start the engine and monitor the voltage as the engine warms up. Compare the readings to expected values. If the voltage rises abnormally high, it could be a sign of a malfunctioning sensor.

Steps to Fix the P1198 Radiator Temperature Sensor Error

Fix the P1198 Radiator Temperature Sensor Error
  • Inspecting and Cleaning: If you find any visible issues during the visual inspection, start by cleaning the connections and repairing or replacing damaged wiring.
  • Testing the Sensor: Use a multimeter to measure the sensor’s resistance and voltage readings. Compare the readings to specifications provided by the manufacturer. Abnormal readings can indicate a faulty sensor.
  • Replacing the Radiator Temperature Sensor: If the sensor is indeed faulty, you’ll need to replace it. Begin by safely removing the old sensor, ensuring you follow manufacturer instructions. When installing the new sensor, make sure to follow proper torque specifications.
  • Verifying Repairs: After replacing the sensor, use the OBD-II scanner to clear the error codes. Take the vehicle for a test drive, paying attention to temperature indicators and any unusual behavior. If the error code doesn’t reappear and the engine operates within the normal temperature range, the issue is likely resolved.

Preventive Measures to Avoid Future Errors

To prevent encountering the P1198 error code in the future:

  • Regular Maintenance: Include routine checks of the radiator temperature sensor and cooling system in your vehicle’s maintenance schedule.
  • Temperature Gauge Monitoring: Keep an eye on your vehicle’s temperature gauge to catch any anomalies early on.
  • Address Warning Signs Promptly: If you notice any unusual engine behavior, warning lights, or temperature fluctuations, don’t delay in investigating and addressing the issue.

P0118 Engine Coolant Temperature Sensor 1 Circuit High

If you’ve been experiencing problems with your vehicle, one of the most likely culprits is a P0118 code, which stands for Engine Coolant Temperature Sensor 1 Circuit High.

First off, let’s discuss what an engine coolant temperature sensor does. It measures the temperature of your engine coolant and sends that information to your car computer (ECU).

The ECU uses this data to determine when certain components should be activated or deactivated based on the current temperature inside your engine block.

For instance, if it detects that temperatures are too high, it might increase airflow into the cylinder head by activating additional fans or opening up more cooling passages in order to keep things running smoothly and safely.

When this trouble code appears, it indicates that there could be something wrong with either the wiring or connector leading from sensor 1 (the first sensor) back to the ECU itself.

Read More: P1282 Fuel Pump Relay Control Circuit Open Or Shorted

P1198 Peugeot

If you’re looking for a reliable, stylish, and affordable car with plenty of features to keep you safe and comfortable on the road, then look no further than the Peugeot P1198.

This compact hatchback is part of the popular French automaker’s “P” line of vehicles that offer an attractive blend of performance, safety, and value.

The exterior design of this vehicle is sleek yet sporty, with its low profile and gently curved lines that give it a distinct look from other cars in its class.

The interior has ample space for five passengers as well as plenty of cargo room in both the trunk and backseat area. Safety features include six airbags (front side-impact bags are optional), ABS brakes, and Electronic Stability Control (ESC) system designed to help maintain control on slippery roads or during evasive maneuvers.

Engine Coolant Temperature Sensor Circuit High

Engine Coolant Temperature Sensor Circuit

The engine coolant temperature sensor (ECT) monitors the temperature of the engine coolant so that the car can adjust its performance accordingly.

If this sensor is sending incorrect information to the computer, other systems may be affected such as fuel delivery, ignition timing, and emissions control.

Fortunately, diagnosing an issue related to a high ECT circuit isn’t too difficult. The first thing you’ll need to do when dealing with this problem checks for any codes associated with it in your vehicle’s diagnostic system. This should give you some clues about what might be going on under the hood.

What Causes High Voltage in a Coolant Sensor?

High voltage in a coolant sensor can be caused by several factors, including a faulty wiring harness, an incorrect connection between the coolant sensor and the vehicle’s engine control unit (ECU), or a defective coolant sensor itself. Here we will explore each of these causes in more detail.

A faulty wiring harness is one of the most common reasons for high voltage readings from a coolant sensor. Over time, wires can become worn or corroded due to environmental conditions such as extreme temperatures and moisture, resulting in poor connections that lead to inaccurate readings from the sensors.

In addition, loose connections or damaged terminals may cause increased resistance within the circuit leading to higher voltages being detected than normal.

What Voltage Should Coolant Temp Sensor Be?

Knowing what voltage should be coming from this sensor is essential for proper operation. The typical range for a coolant temperature sensor is 0-5 volts DC.

This means that the voltage output from your CTS should never exceed 5 volts DC, regardless of how hot it’s getting inside your engine compartment.

If you measure more than 5 volts DC on your multimeter, then there could be an issue with either the wiring or faulty connection somewhere in between which needs to be addressed right away.

In terms of accuracy, most CTS have a tolerance range of plus/minus 2 degrees Celsius (or 3 degrees Fahrenheit). This means that if they detect temperatures outside this range they will not provide accurate readings and may cause problems elsewhere in your car’s systems due to incorrect data being sent out by them.

What Does Engine Coolant Temperature Sensor High Mean?

The Engine Coolant Temperature Sensor (ECT) is responsible for monitoring the temperature of the coolant circulating through your vehicle’s engine cooling system. It does this by measuring the resistance between two wires located inside the ECT.

As temperatures increase, so too does resistance on these wires – allowing current flow and giving off readings that are sent back to other control systems within your car such as ECU and BCM (Body Control Module).

Also Read: P1194 Incorrect Or Irrational Performance Has Been Detected For The Pwm

What is Fault Code P118?

Fault code P118 is an error code that indicates a problem with the fuel pressure regulator in your vehicle. This code can be detected by the engine control module (ECM) when it detects an abnormally high or low pressure reading in the fuel system.

If this issue is not addressed, it could lead to poor performance and even engine damage if left unchecked for too long.

The fault code P118 can occur due to a variety of reasons such as a bad fuel pump, dirty injectors, faulty wiring/connections between components, clogged filters or lines in the fuel system, etc.

It’s important to diagnose and repair any underlying issues before addressing this specific error code so as to ensure optimal performance from your vehicle’s engine.

To start off diagnosing this fault code you would need to check for voltage readings at various points on the circuit board associated with fuel pressure regulating mechanisms such as sensors and actuators etc. Then compare them against the manufacturer’s specifications.

After finding out where exactly things are going wrong you may have to replace certain components depending on what needs attention; like replacing failed parts or cleaning up clogs making sure all connections are intact & secure along the way.

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Frequently Asked Questions

1. What Causes High Voltage In A Coolant Sensor?

High voltage in a coolant sensor can be caused by sensor malfunction, damaged wiring, or engine overheating, leading to inaccurate readings.

2. How Many Volts Should A Coolant Temp Sensor Have?

A coolant temperature sensor typically operates around 0.5 to 4.5 volts, with higher voltage indicating lower temperature and vice versa.

3. What Is The Voltage Above The Upper Limit For The Coolant Temperature Sensor P0118?

The specific voltage value above the upper limit for P0118 can vary by vehicle, but it’s usually around 4.5 to 5 volts.

4. Can High Voltage Cause Overheating?

Yes, high voltage in a coolant temperature sensor can lead to inaccurate readings, potentially causing improper cooling system operation and contributing to overheating.

5. How Do You Reset A Coolant Temperature Sensor?

Resetting a coolant temperature sensor often involves clearing the error codes using an OBD-II scanner after addressing the underlying issue causing the high voltage error.


The P1198 Radiator Temperature Sensor Voltage Too High error might appear daunting, but armed with knowledge, you can tackle it confidently.

Understanding the error’s causes, implications, and diagnostic process empowers you to take prompt action to maintain your vehicle’s performance and longevity.

By regularly monitoring and maintaining your cooling system, you can prevent not only the P1198 error but also a host of other potential issues, ensuring that your vehicle runs smoothly mile after mile.