P1119

Honda

This code, P1119, means 'Manifold Absolute Temperature Circuit High Input'. What that tells us is the Powertrain Control Module, or PCM, is seeing a voltage signal from the Manifold Absolute Temperature sensor that is higher than it expects for the given operating conditions. It's essentially an out-of-range signal.

Time: For an apprentice, budgeting about 1 hour to diagnose and potentially replace the sensor is a good starting point. Once you've done it a few times, you'll see how quickly these jobs can go. | Difficulty: Easy
Medium Severity

The Manifold Absolute Temperature (MAT) sensor is sending a signal to your car's computer that's way too high, making the computer think the air entering the engine is colder than it really is. This can mess with how the engine fuels itself, potentially causing it to run richer or poorer than intended.

Report an error with this code

⚠️ Before You Begin (Safety First)

Always remember, safety first when you're working on any vehicle. Make sure the engine is off and cool before you start poking around, especially near hot components. Disconnect the negative battery terminal to prevent accidental shorts and wear eye protection. We want to learn, but we want to be safe doing it.

Common Symptoms

  • You might notice the engine running a bit rough, particularly during cold starts, because the PCM is misinterpreting the air temperature.
  • Poor fuel economy can creep in, as the engine might be adding too much fuel thinking the air is colder.
  • The Check Engine Light will be on, which is the primary indicator.
  • A noticeable reduction in engine performance or hesitant acceleration, as the engine struggles with an incorrect air-fuel mixture.

Common Causes

  • The Manifold Absolute Temperature (MAT) sensor itself has failed internally, sending an incorrect high voltage signal. This is a common failure point for sensors.
  • A short to voltage in the MAT sensor's wiring harness. This means the wire is touching another power source, sending too much voltage to the PCM.
  • Corrosion or damage at the MAT sensor connector, leading to an intermittent or high resistance connection that the PCM interprets as high voltage.
  • Rarely, a faulty Powertrain Control Module (PCM), but we always rule out the sensor and wiring first before pointing the finger at the computer.

Frequently reported on: 2001-2005 Honda Civic, 2003-2007 Honda Accord, 2002-2006 Honda CR-V, 2005-2007 Honda Odyssey

Diagnostic Steps

  1. Locate the Manifold Absolute Temperature (MAT) sensor on your Honda's intake manifold. It's usually a small sensor threaded into the manifold or snapped into a housing.
  2. Inspect the sensor's electrical connector and wiring for any visible damage, fraying, or corrosion. Make sure the connection is snug.
  3. With the key on, engine off (KOEO), use a multimeter to check the voltage at the MAT sensor's signal wire. Refer to your vehicle's service manual for the expected voltage range. A high reading here would confirm the circuit high input.
  4. If the voltage is out of spec, disconnect the MAT sensor and recheck the voltage at the harness connector's signal wire. If the voltage drops to zero or near zero, the sensor itself is likely faulty. If it remains high, you have a short to voltage in the wiring.
  5. If replacing the sensor, carefully unclip the old sensor, remove it, and install the new one, ensuring it's properly sealed and the electrical connector is securely attached.
  6. Clear the P1119 trouble code using an OBD-II scanner and perform a test drive to confirm the repair.

👨‍🔧 When to Call a Professional

If you've checked the sensor and the wiring and you're still getting the P1119 code, or if you're uncomfortable checking electrical circuits, it's time to call in a certified technician. They have specialized tools and experience to trace complex electrical issues that can sometimes hide behind a simple code.

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Commonly Asked Questions

What exactly does 'high input' mean for this sensor?

When a sensor circuit shows 'high input,' it typically means the voltage signal the PCM is receiving is at or near its maximum possible voltage. For a MAT sensor, this usually indicates an open circuit, a short to voltage, or the sensor itself failing in a way that creates a high resistance or a default high signal.

Can I drive with a P1119 code?

You can probably drive your car, but it's not ideal. The engine's computer will likely be using a default temperature value, which means your fuel mixture won't be perfectly optimized. This can lead to decreased fuel economy and potentially long-term engine issues, so it's best to address it promptly.

Is the MAT sensor the same as the IAT sensor?

That's a great question for an apprentice! Sometimes, yes, they refer to the same component, especially if it's integrated into the MAF sensor or located in the intake manifold. IAT stands for Intake Air Temperature, and MAT stands for Manifold Absolute Temperature. Functionally, they both measure the temperature of the air going into the engine to help the PCM calculate fuel trim.

How do I test the MAT sensor with a multimeter?

First, find the wiring diagram for your specific Honda model. You'll typically be looking for the signal wire. With the sensor connected and the key on, engine off, you'll measure voltage between the signal wire and ground. As the air temperature changes (e.g., you can warm the sensor gently with your hand), the voltage should change smoothly. If it's stuck high or reads open, you've found your culprit.

What if the wiring is the problem, not the sensor?

Good thinking! If you disconnect the sensor and the 'high input' voltage is still present at the harness side of the signal wire, then the problem isn't the sensor. It means that wire is either shorted to a voltage source somewhere else in the harness or there's a fault in the PCM. That's when tracing the wiring harness becomes critical.

Video Repair Guide

Related OBD2 Codes

← P1119 ← P1119 ← P1119 p1119 P1119 → P1119 → P1119 →