P0113 Honda Meaning, Symptoms, Causes, And How To Fix

by

If your Honda’s check engine light is on and you see the code P0113, you’re probably wondering what it means. The P0113 Honda code indicates a problem with your engine’s intake air temperature (IAT) sensor circuit, specifically that it’s reading a voltage that is too high.

This sensor plays a key role in how your engine runs. When it sends an incorrect signal, it can affect performance, fuel economy, and emissions. Don’t worry, though—this guide will explain the symptoms, causes, and how to fix the P0113 code yourself.

P0113 Honda Meaning

In simple terms, P0113 is an OBD-II diagnostic trouble code that means “Intake Air Temperature Sensor 1 Circuit High Input.” Your car’s computer, the Engine Control Module (ECM), monitors the IAT sensor. This sensor tells the ECM the temperature of the air entering the engine.

The ECM uses this data, along with information from other sensors, to calculate the correct air-fuel mixture for optimal combustion. A “high input” means the sensor’s signal voltage is above the normal expected range, typically corresponding to an implausibly cold reading (like -40°F/C) even when the engine is warm.

What Does the Intake Air Temperature (IAT) Sensor Do?

The IAT sensor is a small but vital component. It’s usually located in the air intake duct or inside the mass air flow (MAF) sensor assembly. Its resistance changes with air temperature: high resistance when cold, low resistance when hot.

The ECM sends a reference voltage (often 5 volts) through this resistor. By measuring the voltage that returns, the ECM can determine the air temperature. A high voltage signal indicates high resistance, which the ECM interprets as very cold air.

Why is the IAT Sensor Important?

Cold air is denser than warm air, meaning it contains more oxygen molecules per volume. To burn efficiently, the engine needs more fuel mixed with cold, dense air. The IAT sensor’s reading helps the ECM make these fine adjustments to the fuel injection timing and quantity.

If the signal is wrong, the fuel mixture will be off. This can lead to several driveability issues you might notice.

Symptoms of a P0113 Code

You might experience one or more of these symptoms when the P0113 code is stored in your Honda’s ECM:

  • Check Engine Light: This is the most common and obvious first sign. The light will illuminate on your dashboard.
  • Poor Fuel Economy: Since the ECM may think the intake air is colder than it actually is, it could enrich the fuel mixture unnecessarily, causing you to use more gas.
  • Rough Idle or Stalling: An incorrect air-fuel mixture can make the engine run unevenly at idle or even cause it to stall, especially when cold.
  • Reduced Engine Performance: You might feel a lack of power or hesitation during acceleration. The engine may feel sluggish.
  • Hard Starting: In some cases, the overly rich mixture could make the engine harder to start, particularly when it’s actually warm outside.
  • Other Codes: Sometimes, P0113 appears alongside other sensor codes, like those for the MAF sensor, as they are often related.

Common Causes of P0113 in Honda Vehicles

Figuring out the root cause is the key to a proper fix. Here are the most likely culprits for a P0113 code on your Honda:

  • Faulty IAT Sensor: The sensor itself can fail internally, giving an incorrect high-resistance signal.
  • Open or Damaged Wiring: A broken wire, corroded connector, or poor connection in the IAT sensor circuit can create infinite resistance, which the ECM sees as a very high voltage signal.
  • Short to Voltage in the Circuit: If the sensor’s signal wire is shorted to another power source (like a chafed wire touching a 12V circuit), it will send a constantly high voltage to the ECM.
  • Poor Electrical Connection: Corrosion, dirt, or looseness at the sensor connector or the ECM connector can disrupt the signal.
  • Issues with the MAF Sensor: On many Hondas, the IAT sensor is integrated into the MAF sensor assembly. A problem within the MAF housing can affect the IAT signal.
  • Rarely, a Faulty ECM: While uncommon, the engine computer itself could have an internal fault that prevents it from reading the sensor correctly.

How to Diagnose and Fix P0113

You can often diagnose this problem with basic tools. Always prioritize safety: let the engine cool, disconnect the battery before working on electrical parts, and work in a well-ventilated area.

Tools You Will Likely Need

  • Basic hand tools (screwdrivers, sockets)
  • Digital multimeter (DMM)
  • Scan tool or OBD2 code reader (to clear the code after repair)
  • Electrical contact cleaner
  • Repair manual for your specific Honda model (for wiring diagrams)

Step-by-Step Diagnostic Guide

Step 1: Visual Inspection

Start with the simplest things first. Locate the IAT sensor. It’s typically in the air intake hose between the air filter box and the throttle body, or as part of the MAF sensor.

  • Check the air intake system for any leaks or disconnections before the sensor.
  • Inspect the sensor’s electrical connector. Look for signs of damage, corrosion, or if it’s loose. Unplug it and check both the connector and the sensor terminals.
  • Follow the wiring harness from the sensor back a short distance. Look for any obvious damage, melting, or chafing where wires might be exposed.

Step 2: Test the IAT Sensor Resistance

If the wiring looks good, test the sensor itself. You’ll need your multimeter set to measure resistance (Ohms).

  1. Disconnect the electrical connector from the IAT sensor.
  2. Place the multimeter probes on the two terminals of the sensor (not the wiring harness).
  3. Note the resistance reading at the current ambient temperature. You can use a separate thermometer for reference.
  4. Warm the sensor gently with your hand or a hairdryer. The resistance should drop smoothly as the sensor warms up. A faulty sensor will show no change, an open circuit (infinite resistance), or a short (zero resistance).

Compare your readings to specifications if you have them. Generally, a good sensor should show several thousand ohms when cold and several hundred when warm.

Step 3: Check the Wiring and Voltage

This step checks the circuit from the ECM to the sensor connector.

  1. Reconnect the sensor connector. Carefully back-probe the wires at the connector with your multimeter probes (use thin pins if needed).
  2. With the key in the “ON” position (engine off), check for reference voltage (usually around 5 volts) on the correct wire (consult a wiring diagram).
  3. Check the ground wire for continuity to a good engine ground.
  4. Check the signal wire for continuity back to the ECM connector, and check for any short to power or ground.

Step 4: Check for Related Issues

If the sensor and wiring test good, consider other factors. A vacuum leak upstream of the sensor can sometimes cause strange readings. Also, if your Honda has a separate MAF sensor, check for any related codes or issues with it, as they work closely together.

Repair Procedures

Based on your diagnosis, here are the common fixes:

1. Cleaning the Sensor and Connector

If you found minor corrosion, this might solve it.

  1. Spray electrical contact cleaner on the sensor terminals and into the connector.
  2. Gently scrub with a soft brush if needed.
  3. Let it dry completely before reconnecting.
  4. Clear the code and see if it returns.

2. Repairing Damaged Wiring

For broken or chafed wires:

  1. Cut out the damaged section of wire.
  2. Splice in a new piece of similar gauge automotive wire using solder and heat-shrink tubing (or quality crimp connectors).
  3. Secure the repaired harness away from heat or sharp edges.

3. Replacing the IAT Sensor

If the sensor tests bad, replacement is straightforward.

  1. Disconnect the negative battery terminal.
  2. Unplug the electrical connector from the old sensor.
  3. Unscrew or unclip the sensor from its housing (often a single screw or a push-in clip).
  4. Install the new sensor, reconnect the wiring, and reconnect the battery.
  5. Clear the DTC with your scan tool.

4. Replacing the MAF/IAT Assembly

On models where they are combined, you must replace the entire MAF sensor assembly. The process is similar to replacing just the IAT, but the part is more expensive. Be sure to get the correct part number for your Honda.

Clearing the P0113 Code

After making the repair, you need to clear the code from the ECM’s memory. Use your OBD2 scan tool to clear the codes. Then, drive the car through a variety of conditions (city, highway) for at least 10-15 minutes. This allows the ECM to run its self-tests. If the repair was successful, the check engine light should stay off.

If you don’t have a scan tool, you can disconnect the car battery for about 15 minutes. This will often clear the codes, but it may also reset other learned settings in the radio and ECU, so a scan tool is preferred.

FAQs About Honda P0113

Can I drive my Honda with a P0113 code?

You can usually drive for a short time, but it’s not recommended for the long term. You may experience poor fuel economy and performance, and the incorrect fuel mixture could potentially damage the catalytic converter over time. Schedule the repair as soon as you can.

Is P0113 a serious code?

It’s generally considered a moderate severity code. It won’t typically leave you stranded immediately, but it does affect engine operation and emissions. Ignoring it can lead to further problems and increased repair costs.

How much does it cost to fix P0113?

Costs vary widely. If it’s just a loose connection, almost nothing. A new IAT sensor costs between $30 and $100 for the part. If you need a combined MAF/IAT sensor, it could be $150-$300 for the part. Labor at a shop might add $100-$200, but this is a very common DIY repair for many owners.

What’s the difference between P0112 and P0113?

P0112 is “IAT Sensor Circuit Low Input,” meaning the signal voltage is too low (indicating an implausibly hot reading). P0113 is the opposite: “High Input.” Both point to issues in the same circuit but at opposite ends of the voltage spectrum.

Could bad gas cause a P0113 code?

No, bad fuel would not directly cause an IAT sensor circuit code. The P0113 is specifically an electrical circuit issue related to the sensor or its wiring.

Dealing with a P0113 code on your Honda is very manageable with a methodical approach. Start with a simple visual inspection, test the sensor and its circuit, and you’ll likely find the root cause. Fixing it yourself can save you money and get your Honda running smoothly again. Remember, if you’re ever unsure about a step, consulting a professional mechanic is always a good option.