P0113 on 2006-2013 Lexus IS: Intake Air Temp Sensor Causes and Fixes

What's Unique About the 2006-2013 Lexus IS

On the second-generation Lexus IS (models IS250 and IS350), the Intake Air Temperature (IAT) sensor is not a standalone part. Instead, it is integrated directly into the Mass Airflow (MAF) sensor housing, located in the engine's air intake tube right after the air filter box. This means that if the IAT sensor fails, the entire MAF sensor assembly must be replaced. Fortunately, this is a common, easy-to-access part shared across many Toyota and Lexus models, making it readily available.

Symptoms You May Notice

• Check Engine Light is on
• Check VSC light may also illuminate
• Difficulty starting the engine, or engine cranks but will not start, especially in cold weather
• Reduced fuel economy
• Rough idle or stalling
• Hesitation or poor acceleration
• Black smoke from exhaust on startup due to rich fuel mixture

Most Likely Causes

1. Failed MAF/IAT Sensor Assembly 🔴 High Probability The IAT sensor is integrated into the MAF sensor, which is a common failure point due to age and heat cycles. An internal open circuit in the IAT thermistor portion of the sensor is the most frequent trigger for P0113.
   How to confirm: Use an OBD-II scanner to view live data. If the IAT reading is stuck at -40°F or a similarly low value, the sensor has failed. You can also test the sensor with a multimeter. At ~70°F (20°C), the resistance across the IAT pins should be around 2-3 kΩ. If the reading is infinite (open circuit), the sensor is bad.
   Typical fix: Replace the entire Mass Airflow (MAF) sensor assembly. Cleaning the sensor with dedicated MAF cleaner can be attempted first, but it rarely fixes an internal circuit fault.
   Est. part cost: $120-$220
2. Damaged Wiring or Connector 🟡 Medium Probability Wiring can become brittle over time from engine heat. The 5-pin connector (Part No. 90980-11858 or similar) can also be damaged or become loose during air filter changes or other maintenance if not handled carefully.
   How to confirm: Visually inspect the wiring harness leading to the MAF sensor for any cuts, fraying, or signs of rodent damage. Check that the connector is securely plugged in and that the pins inside are clean and not corroded or bent. With the key on and engine off, unplug the connector and test the reference wire; it should have ~5 volts.
   Typical fix: Repair the damaged section of wire or replace the pigtail connector if it is broken. Pigtail part numbers include 90980-12292 and 90980-11317.
   Est. part cost: $15-$40
3. Dirty MAF/IAT Sensor ⚪ Low Probability Over-oiled aftermarket air filters can contaminate the sensor elements. While this more commonly causes performance codes (like P0171/P0174) or MAF codes (P0102), it can occasionally interfere with the IAT circuit.
   How to confirm: Remove the sensor and inspect the sensing elements. If they are covered in dirt, oil, or debris, this is a likely contributor.
   Typical fix: Spray the sensor elements thoroughly with a dedicated Mass Airflow Sensor cleaner. Do not touch the elements or use any other type of chemical. Let it dry completely before reinstalling. 🎬 See how to clean the MAF sensor and throttle body
   Est. part cost: $10-$15

Rare But Worth Checking

• Faulty Engine Control Module (ECM): → Shop Engine Control Module (ECM) This is extremely rare. Before suspecting the ECM, all other possibilities, including the sensor and its entire circuit, must be exhaustively tested and ruled out. This would typically be accompanied by other trouble codes.

Diagnosis Steps

1. Connect an OBD-II scanner and confirm P0113 is the active code. Check for any other codes like P0102.
2. View the live data stream for the Intake Air Temperature (IAT). Confirm that it reads an illogical, extremely low value, such as -40°F (-40°C), regardless of the actual ambient temperature. This strongly points to an open circuit.
3. Turn off the ignition and locate the MAF sensor on the air intake tube, just after the air filter housing.
4. Carefully inspect the electrical connector and wiring harness going to the MAF sensor. Wiggle the connector while monitoring live data (if possible) to see if the reading changes. Look for loose connections, corrosion on the pins, or any visible damage to the wires.
5. If the wiring looks good, try cleaning the sensor. Remove the MAF sensor (typically held by two Phillips head screws).
6. Spray the sensor's internal wires and thermistor bulb with dedicated MAF sensor cleaner. Do not touch the delicate components. Allow it to air dry completely.
🎬 Watch: Simple cleaning steps for Lexus hotwire MAF sensors
7. Reinstall the cleaned sensor, clear the codes, and start the engine. Check the live data again. If the IAT now reads a plausible temperature, the issue may be resolved, but be prepared for it to return if the failure is internal.
8. If the code returns and the reading is still -40°F, the MAF/IAT sensor assembly has failed internally and needs to be replaced. This is the most common outcome for a P0113 code on this platform.
9. If a new sensor does not fix the issue, perform a circuit integrity test. Check for 5V reference and a good ground at the connector. Test for continuity on the signal wire between the MAF connector and the ECM.

Parts You'll Likely Need

• Mass Airflow (MAF) Sensor (OEM #22204-31020) — This assembly contains the integrated IAT sensor that fails and causes the P0113 code. Replacement of the entire unit is the definitive fix. 🎬 Watch: Step-by-step Lexus IS250 MAF sensor replacement guide This part supersedes previous numbers 22204-31010 and 22204-0H010.
  Trusted brands: Denso (OEM), Hitachi, Bosch, Walker
  OEM price range: $150-$215
  Aftermarket price range: $70-$130
• MAF Sensor Connector Pigtail (OEM #90980-12292 / 90980-11858) — Needed if the original connector housing is cracked, broken, or the wires are corroded at the connector body.
  Trusted brands: Dorman, Standard Motor Products, OEM
  OEM price range: $25-$40
  Aftermarket price range: $15-$25

Related Codes That Often Appear With This One

• P0102 — Mass Air Flow (MAF) Circuit Low. Since the IAT and MAF sensors are in the same housing and share a connector, a bad connection or faulty sensor assembly can trigger both codes simultaneously.

Platform-Specific Known Issues

• Owner Experience: Connector Not Fully Seated: A user on ClubLexus reported chasing a P0113 code. After cleaning the sensor didn't work, they were about to order a new one. On a final check, they realized the connector wasn't fully 'clicked' into place. After unplugging it, cleaning the pins with contact cleaner, and firmly reseating it until it clicked, the code was cleared and did not return. This highlights the importance of checking the simple things first before buying parts.

Diagnostic Flowchart

Other Known Issues on This Vehicle

Issues unrelated to this code that are worth knowing about as an owner of this generation:

• Carbon Buildup on Intake Valves (IS250 / 4GR-FSE) 🔴 High — Very common, especially on vehicles used for short trips. Symptoms like rough idle, misfires, and hesitation can appear after 60,000 miles. (Ref: Lexus issued Technical Service Bulletins (TSBs) for a top engine cleaning procedure. In severe cases, a piston and ring replacement was performed under warranty.)
• Sticky / Melting Dashboard and Door Panels 🟠 Medium — Extremely common in hot, humid climates. The material degrades under UV/heat exposure, becoming shiny, sticky, and prone to damage. (Ref: Lexus initiated a Warranty Enhancement Program (ZLD/ZLZ) to replace affected panels, but this program had an expiration date and many vehicles were missed.)
• Water Pump Failure (IS350 / 2GR-FSE) 🔴 High — A well-documented failure point, typically occurring between 60,000 and 100,000 miles. Failure often starts as a slow leak from the weep hole, leaving pink/white crusty residue. (Ref: No recall, but updated water pump parts were released. Failure can be catastrophic if it leads to rapid coolant loss and overheating.)
• Clogged A/C Condensate Drain Line 🟡 Low — Can occur at any time, leading to water soaking the passenger side floor carpet. This can cause mold, mildew smells, and potential damage to electronics under the carpet.

Real Owner Stories

Aggregated from forums and TSBs cited above. Mileages and costs reflect what owners reported in those sources.

Related OBD-II Codes

• P0102 — Mass Air Flow (MAF) Circuit Low Input; often appears with P0113 because the IAT and MAF sensors are housed in the same physical assembly and share a connector.
• P0171 — System Too Lean (Bank 1); can be triggered if a contaminated or failing MAF/IAT sensor (often from over-oiled filters) provides incorrect air data to the ECM.
• P0174 — System Too Lean (Bank 2); similar to P0171, this code can result from MAF sensor contamination interfering with the air-fuel mixture calculation.

Frequently Asked Questions