No, P0113 is low-priority. Unlike misfire codes or oxygen sensor faults, this code does not damage emissions or cause drivability problems. The engine will run normally. The code is triggered simply because the ECU saw an impossible reading, not because combustion is compromised. It's a nuisance code that should be addressed, but you can safely drive to a garage.

Can the IAT sensor fail partially?

Yes. IAT sensors can drift over time, giving slightly inaccurate readings. If the sensor reads gradually higher or lower, the ECU may not flag it until it exceeds the threshold. A sensor that reads 50°C instead of 30°C might not trigger P0113, but one that reads 120°C will.

Why is the MAF sensor mentioned?

On many vehicles, the IAT sensor is integrated into the MAF sensor assembly (Mass Air Flow). If the MAF is replaced, both sensors are replaced together as one unit. This is why MAF replacement is relevant to P0113 diagnosis.

Will clearing the code help?

Temporarily, yes. If the sensor has gone bad, clearing the code will only cause it to reappear after a few drive cycles. If the fault was a transient wiring issue or a loose connector, clearing the code might solve it permanently. Always fix the root cause rather than just clearing the code.

Will P0113 cause an MOT failure?

Yes, through the warning light: an EML on at test time is a Major failure. The sneakier problem is that an intake air temperature sensor reading -40°C makes the ECU fuel as if it is arctic, running rich constantly - that shows up directly in the emissions figures. On most cars the IAT sensor is built into the MAF, so if you replace one for the MOT, you are usually replacing both.

P0113 - Intake Air Temperature Sensor High Input

What Is P0113?

P0113 is an intake air temperature (IAT) sensor fault code. The IAT sensor measures the temperature of air entering the engine and sends a voltage signal to the ECU. The ECU uses this to adjust fuel mixture and ignition timing - cold air is denser and needs more fuel; hot air is thinner and needs less fuel. P0113 means the ECU received a signal indicating an implausibly high air temperature (typically above 80–100°C), which is impossible under normal conditions. The only way intake air can be that hot is if the engine bay itself is catastrophically overheating, which would trigger other codes.

P0113 usually indicates a faulty IAT sensor or wiring issue. The good news: this code does not affect drivability or cause emissions damage. Your engine will still run fine, albeit with adjusted fuel trim based on the false reading.

Common Symptoms

Check engine light illuminated (no drivability issues)
Slightly rough idle or hesitation (minor, not critical)
Possible slight change in fuel economy
Cold-start difficulty (ECU thinks air is hot, reduces fuel)
No other engine problems or warning lights

Common Causes

Faulty IAT SensorThe sensor element has failed, sending an erratic signal or stuck at maximum voltage, which the ECU interprets as extreme temperature.

Wiring DamageThe sensor wiring is damaged or corroded, causing the signal to be misread by the ECU as a high voltage, indicating high temperature.

Loose or Corroded ConnectorA poor connection at the sensor or ECU input creates intermittent or falsely high voltage signals.

ECU Input Circuit FaultThe ECU's IAT input circuit is malfunctioning, misinterpreting normal sensor signals as high temperature readings.

Sensor Calibration DriftThe sensor has drifted out of calibration over time, reading consistently higher than actual temperature.

Engine Bay OverheatingRarely, if the engine compartment is genuinely overheating due to cooling system failure, the IAT will read high. Check for coolant leaks or thermostat failure.

How to Diagnose P0113

Inspect the IAT Sensor Connector

Locate the intake air temperature sensor (typically mounted in the intake manifold or air intake tube). Disconnect the connector and inspect for corrosion, bent pins, or water damage. Clean any corroded connectors with electrical contact cleaner. Reseat the connector firmly, clear the code, and retest.

Check Sensor Wiring

Trace the IAT sensor wiring from the connector to the ECU, looking for cuts, abrasions, heat damage, or pinched sections. Check for rodent damage or chafing against sharp edges. If damage is found, repair the wiring. Sometimes the IAT is part of the MAF sensor assembly - check your vehicle's diagram.

Monitor Sensor Voltage on Scanner

Connect an OBD scanner and monitor the IAT sensor voltage or temperature reading in live data mode. A normal reading at idle/cold start should be between 0.5V and 2.5V (roughly 10–70°C depending on climate). If the voltage is stuck at a high value (3.5V+) or fluctuates wildly, the sensor is faulty.

Test Sensor Resistance

Disconnect the IAT sensor. Using a multimeter set to resistance mode, measure the sensor element. Most IAT sensors have a resistance of 5K–10K ohms at room temperature. Infinite resistance or zero ohms indicates a failed sensor. Compare to your vehicle's specification.

Check Coolant Level and Temperature

Rule out genuine engine overheating. Check coolant level (should be full when cold). Run the engine and monitor coolant temperature on the scanner. If it's normal (85–95°C), the engine is fine and the IAT sensor is faulty. If coolant is genuinely hot (above 100°C), investigate cooling system issues first.

Low Priority Code P0113 is unusual because it's a drivability code without serious consequences. Your engine runs fine, the catalyst is not harmed, and emissions are only slightly affected. Fix it when convenient, not urgently.

Verdict

P0113 is usually a faulty IAT sensor (£80–£200 for part and labour) or a corroded connector (free fix). Start with connector inspection and cleaning. If that doesn't work, test the sensor voltage with a scanner. If the sensor is faulty, replacement is straightforward - typically a £200–£300 repair. Unlike critical sensor faults (crank, cam), you can safely ignore this code while diagnosing.

Want the full picture? The OBD Fault Code Plain English Guide (PDF) covers the most common UK fault codes in one plain-English download.