Yes. In most emissions inspection programs, a P0118 that has set the MIL (malfunction indicator light) will cause a failure on the OBD-II portion of the test. Whether you fail can depend on your state’s rules and whether the readiness monitors have completed. This article explains what P0118 means, how it can affect inspections, and what you can do about it.
What P0118 means for your Honda
The code P0118 refers to the MAP/Barometric Pressure Sensor Circuit High Input. The MAP sensor provides data to the engine control unit (ECU) to estimate engine load and determine fuel delivery. When the sensor signal appears higher than expected, the ECU can set the MIL and store P0118. In practice, this can affect engine performance and fuel economy, though drivability can vary by model and severity.
Typical symptoms you might notice
When P0118 is active, some drivers report one or more of the following symptoms, though not every car will exhibit all of them:
- Rough idle or intermittent stalling
- Power or acceleration hesitation
- Reduced fuel economy
- Check Engine Light (MIL) illuminated on the dashboard
Common causes of P0118 include the following:
- Faulty MAP sensor (the most frequent culprit)
- Damaged, corroded, or loose wiring or connector in the MAP circuit
- Electrical shorts or opens in the MAP circuit (to 5V or ground)
- PCM/ECU fault affecting MAP readings
- Vacuum or intake pressure issues that affect readings or sensor mounting
If you see P0118, a diagnostic check by a qualified technician is recommended to confirm the exact cause and prevent further problems. After any needed repairs, codes should be cleared and a proper drive cycle completed to re-check readiness.
Will P0118 cause my Honda to fail inspection?
In most jurisdictions that use OBD-II based emissions testing, a stored P0118 with the MIL on will trigger a failure on the OBD-II portion of the inspection. If the MIL is off but the code remains stored, some programs may still require that readiness monitors be fully ready, and a failure can occur if tests cannot complete properly. Local rules vary, so always verify with your state or local vehicle inspection program.
Key factors that influence the outcome include the following:
- Whether the MIL is currently illuminated (codes with the MIL on generally fail the OBD-II test)
- Whether OBD readiness monitors have completed an acceptable drive cycle
- Specific state inspection rules, as some jurisdictions have non-OBD or limited checks for older vehicles
- Whether the inspection is strictly visual or also includes an OBD-II emissions check
Conclusion: To improve your odds, fix the underlying MAP sensor issue, clear the codes, and drive through a proper drive cycle to re-establish readiness before your inspection. Always confirm with your local DMV or inspection station for exact requirements in your area.
What to do if you’re preparing for inspection
If P0118 is present, follow these steps to maximize your chances of passing the inspection:
- Have the MAP sensor and related wiring inspected and repaired as needed
- Replace a faulty MAP sensor and repair any damaged harnesses or connectors
- Check for vacuum leaks and confirm proper routing of intake hoses
- Clear the codes with an OBD-II scanner and perform a complete drive cycle to set readiness
- Verify with a local shop or dealership that the vehicle passes the OBD-II portion after repairs
Next steps if you’re unsure: take your Honda to a trusted mechanic or your local emissions testing center for a pre-inspection diagnostic. They can confirm the exact cause of P0118 and whether the vehicle is likely to pass or fail the upcoming inspection.
Summary
P0118 indicates a MAP/Barometric Pressure Sensor Circuit High Input and commonly triggers the MIL. In most places, that combination will cause an OBD-II emission inspection to fail unless the issue is repaired and the readiness monitors pass. Repair the MAP sensor or its wiring, clear codes, and complete a drive cycle to improve your chances. Always check your state’s specific inspection rules, because requirements can vary.
Will a P0118 code cause my car to fail inspection?
Driving your vehicle in the short term with a code P0118 might result in reduced fuel economy, increased emissions, and a failed emission test.
What happens if I drive with a bad coolant temperature sensor?
Engine overheating – If your sensor malfunctions, the ECU might not regulate the engine temperature properly with the cooling fans, causing overheating. Poor fuel economy – A faulty sensor can disrupt fuel mixture adjustments, leading to excessive fuel consumption.
What causes a P0118 code on a Honda?
What does the P0118 error code mean? The P0118 diagnostic trouble code stands for "Engine Coolant Temperature Sensor Circuit High Input." This code is triggered when the engine control module detects an abnormally high voltage signal from the engine coolant temperature sensor.
How serious is the P0118 code?
How Serious Is the P0118 Code? The P0118 code will often put your vehicle into a failsafe mode, which can cause the engine to run rough or hesitate until it warms up to operating temperature. Because of this failsafe mode, your vehicle may experience excessive fuel consumption and carbon fouling of engine components.