P0118 - Understanding DTC P0118: Coolant Temperature Sensor Circuit High Input - Common Issues in Ford, Chevy, and Honda Models

Quick Answer

P0118 means: DTC P0118 indicates a high voltage signal from the coolant temperature sensor, pointing to a potential issue in the sensor or its circuit.

Fix: Check and replace faulty components Cost: $100 - $300 Time: 90-180 minutes

Can I drive with P0118? Immediate diagnosis is recommended to prevent engine overheating.

Common Questions

What does P0118 mean and how does it affect my car?

The P0118 code indicates that the coolant temperature sensor is sending a high voltage signal, which can lead to poor engine performance and potential overheating. This code affects your car's ability to regulate engine temperature effectively, possibly resulting in increased fuel consumption and engine damage if not addressed.

What are the most common causes of P0118 and how much does it cost to fix?

The most common cause of P0118 is a faulty coolant temperature sensor, which can cost between $100 and $300 to replace. Other causes include wiring issues and in rare cases, a malfunctioning ECM, which can be much more expensive to fix, ranging from $800 to $1500.

Can I drive my car with P0118 or should I stop immediately?

It is not advisable to continue driving your vehicle with a P0118 code. The high voltage signal can cause your engine to overheat, leading to severe damage. If the check engine light is illuminated and there are performance issues, it's best to stop driving and have the vehicle diagnosed as soon as possible.

How can I diagnose P0118 myself using GeekOBD APP?

You can diagnose P0118 by using the GeekOBD APP to scan your vehicle's OBD2 system. The app will retrieve the fault codes and provide freeze frame data, allowing you to see the conditions under which the fault occurred. From there, you can perform a visual inspection of the coolant temperature sensor and its wiring.

What vehicles are most commonly affected by P0118?

DTC P0118 commonly affects vehicles such as the 2015-2018 Ford F-150, 2010-2015 Chevy Camaro, and 2013-2017 Honda Accord. It's always a good idea to check for any recalls or technical service bulletins related to these models for additional guidance.

How can I prevent P0118 from happening again?

To prevent P0118 from recurring, ensure regular maintenance of your vehicle's cooling system, including checking for leaks and replacing coolant as needed. Additionally, inspect electrical connections for corrosion and wear periodically to maintain proper functionality.

What is P0118?

DTC P0118 is a diagnostic trouble code that indicates a problem with the coolant temperature sensor circuit, specifically when the voltage input is too high. This code is commonly found in various vehicle makes, including Ford, Chevrolet, and Honda, particularly models like the 2015-2018 Ford F-150, 2010-2015 Chevy Camaro, and 2013-2017 Honda Accord. The coolant temperature sensor plays a crucial role in monitoring the engine's temperature and relaying this information to the engine control module (ECM). When the sensor sends a voltage signal that is higher than expected, it can lead to inaccurate readings of the coolant temperature. This can cause the engine to run inefficiently, potentially leading to overheating and increased emissions. Drivers may notice symptoms such as poor fuel economy, erratic engine performance, or the check engine light illuminating. Ignoring this code can lead to more serious engine issues and costly repairs down the line, so it’s essential to address it promptly.

System: P - Powertrain (Engine, Transmission, Emissions)

Symptoms

Common symptoms when P0118 is present:

  • Check engine light stays on constantly, indicating a persistent issue that requires attention.
  • Engine hesitates during acceleration, leading to a noticeable decline in driving performance.
  • Fuel economy decreased by 10-15%, costing drivers more at the pump due to inefficient engine operation.
  • Overheating warning may appear on the dashboard, signaling potential damage to the engine.
  • Rough idle or stalling, especially during cold starts, can affect overall drivability.

Possible Causes

Most common causes of P0118 (ordered by frequency):

  1. Faulty coolant temperature sensor (60%) - This is the most common cause and can be identified through simple testing with a multimeter.
  2. Wiring issues or loose connections (25%) - Damaged wires or poor connections can disrupt the signal, leading to high voltage readings.
  3. Faulty engine control module (10%) - Although rare, a malfunctioning ECM can misinterpret sensor data, resulting in a false high voltage signal.
  4. Corrosion at connector points (3%) - Corrosion can lead to poor conductivity, causing the sensor to send incorrect readings.
  5. Shorted wires (2%) - A short circuit in the wiring can cause the sensor to send an unusually high voltage signal.

P0118 Repair Costs

Cost Breakdown by Repair Type

Coolant Temperature Sensor Replacement

Replacing the faulty coolant temperature sensor typically resolves the P0118 code.

  • Total: $100 - $300
  • Success rate: 90%
Wiring Repair

Repairing or replacing damaged wiring or connections can eliminate causes of false readings.

  • Total: $50 - $150
  • Success rate: 80%
ECM Replacement

In rare cases, replacing the engine control module may be necessary if it is determined to be faulty.

  • Total: $800 - $1500
  • Success rate: 70%
Money-Saving Tips for P0118
  • Start with the most common and least expensive repairs first
  • Use GeekOBD APP to confirm diagnosis before replacing expensive parts
  • Consider preventive maintenance to avoid future occurrences
  • Compare prices for OEM vs aftermarket parts based on your needs
  • Address the issue promptly to prevent more expensive secondary damage

Diagnostic Steps

Professional P0118 Diagnosis Process

Follow these systematic steps to accurately diagnose P0118. Each step builds on the previous one to ensure accurate diagnosis.

Step 1: Step 1: Initial visual inspection - Check for obvious signs like damaged wiring, loose connections, or corrosion (5-10 minutes)

Step 1: Initial visual inspection - Check for obvious signs like damaged wiring, loose connections, or corrosion (5-10 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.
Step 2: Step 2: OBD2 scan with GeekOBD APP - Retrieve all codes and freeze frame data to understand the fault context (10-15 minutes)

Step 2: OBD2 scan with GeekOBD APP - Retrieve all codes and freeze frame data to understand the fault context (10-15 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.
Step 3: Step 3: Component testing - Use a multimeter to test the coolant temperature sensor for voltage output (20-30 minutes)

Step 3: Component testing - Use a multimeter to test the coolant temperature sensor for voltage output (20-30 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.
Step 4: Step 4: System function test - Verify proper operation of the sensor and circuit after repairs and clear codes (10-15 minutes)

Step 4: System function test - Verify proper operation of the sensor and circuit after repairs and clear codes (10-15 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.
Step 5: Step 5: Road test verification - Drive vehicle under various conditions to confirm repair success and proper sensor function (15-20 minutes)

Step 5: Road test verification - Drive vehicle under various conditions to confirm repair success and proper sensor function (15-20 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.

Important Notes

  • Always verify the repair with GeekOBD APP after completing diagnostic steps
  • Clear codes and test drive to ensure the problem is resolved
  • Address underlying causes to prevent code recurrence

Real Repair Case Studies

Case Study 1: Coolant Temperature Sensor Replacement on a 2015 Ford F-150

Vehicle: 2015 Ford F-150, 75,000 miles

Problem: Customer reported check engine light and poor fuel economy.

Diagnosis: The OBD2 scan revealed a P0118 code. Visual inspection showed a damaged coolant temperature sensor.

Solution: Replaced the coolant temperature sensor and cleared the fault code.

Cost: $150 (sensor cost and labor included)

Result: Customer reported improved fuel economy and no check engine light after repair.

Case Study 2: Wiring Repair on a 2010 Chevy Camaro

Vehicle: 2010 Chevy Camaro, 85,000 miles

Problem: Engine stalling and overheating warning light appeared.

Diagnosis: OBD2 scan indicated a P0118 code. Inspection revealed frayed wiring near the coolant temperature sensor.

Solution: Repaired the damaged wiring and secured all connections.

Cost: $100 (labor and materials included)

Result: Vehicle operated normally after repairs, with no further issues reported.

Diagnose P0118

Use GeekOBD APP for professional diagnosis!

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Code Information

Code: P0118
System: Powertrain (Engine, Transmission, Emissions)
Severity: HIGH
Category: Engine Codes