P0113

Intake Air Temperature Circuit High Input Bank 1

P0113 is a generic OBD-II powertrain diagnostic trouble code: Intake Air Temperature Circuit High Input Bank 1. It is logged by the engine control unit when the air/maf monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.

Code
P0113
Group
Powertrain
System
Air/MAF
Severity
Warning (MIL on)
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What P0113 means

P0113 is an SAE generic powertrain code that sets when the Powertrain Control Module (PCM) detects an abnormally high voltage signal on the Intake Air Temperature (IAT) Sensor 1 circuit — typically above 4.9 V, which corresponds to a calculated air temperature of approximately −40 °F / −40 °C. The IAT sensor is a two-wire negative-temperature-coefficient (NTC) thermistor: as air temperature rises, the sensor's internal resistance falls and the signal voltage to the PCM decreases. A high voltage reading therefore indicates an open circuit, a missing ground reference, or a failed sensor rather than genuinely cold air.

The IAT sensor is most commonly located in the air filter housing, the intake air duct, or integrated into the Mass Air Flow (MAF) sensor assembly. The PCM supplies a regulated reference of approximately 4.6–5 V on one wire and expects a varying return voltage on the signal wire. When the return voltage is stuck high, the PCM cannot accurately determine air density, which it uses to calculate injector pulse width and ignition timing. Many PCMs substitute a default value (often 101 °F / 38 °C) as a fail-safe, masking the fault during warm operation.

Although P0113 rarely triggers limp mode on its own, it can cause cold-start fuelling errors when ambient temperatures drop significantly and the substituted default value is far from reality. This mismatch can cause excessive fuel enrichment, spark plug fouling, and hard or no-start conditions in winter. P0113 is the 'high' counterpart to P0112 (circuit low); together they bracket the normal operating range of the IAT circuit.

Common causes

Most-frequently reported root causes when P0113 is logged.

  • 1
    Open circuit in the IAT sensor signal or ground wiring (broken wire, damaged harness)
  • 2
    Corroded, loose, or damaged IAT sensor connector terminals
  • 3
    Failed IAT sensor (internal open in the NTC thermistor element)
  • 4
    Short to positive voltage on the IAT signal wire
  • 5
    Defective or missing sensor ground path
  • 6
    IAT sensor integrated into MAF assembly — faulty MAF assembly
  • 7
    Excessive resistance in wiring due to rodent damage or chafing
  • 8
    Rare: PCM fault or software issue causing misinterpretation of sensor voltage

Symptoms drivers notice

Check Engine Light (MIL) illuminated
Hard start or no-start in cold ambient conditions
Rough idle or hesitation during cold engine warm-up
Reduced fuel economy due to incorrect air-density calculation
Possible black smoke or rich-running condition in cold weather
Scan tool shows IAT reading frozen at −40 °F / −40 °C or a fixed default value (e.g. 101 °F)

How to diagnose P0113

A typical diagnostic flow when this code is present.

  1. 1
    Connect a scan tool and record live IAT sensor data; confirm the reading is stuck at −40 °F / −40 °C (or a fixed default) with the key on, engine off
  2. 2
    Visually inspect the IAT sensor connector and wiring harness for corrosion, spread terminals, chafing, or open breaks; clean or repair as needed before electrical testing
  3. 3
    With ignition on and sensor connector disconnected, measure voltage on the reference wire — expect approximately 4.6–5 V; a missing reference voltage points to a PCM or wiring fault upstream
  4. 4
    With the sensor disconnected and ignition on, use a jumper wire to briefly short the two sensor terminals together and verify the scan tool (or stored code) switches to P0112 (circuit low) — this confirms the circuit is intact to the PCM and isolates the fault to the sensor itself
  5. 5
    With ignition off, measure resistance across the sensor terminals and compare to the manufacturer's temperature–resistance chart (typical: ~37 kΩ at 20 °C / 68 °F); an out-of-range or open-circuit (OL) reading confirms sensor failure
  6. 6
    Test signal and ground wire continuity from the sensor connector back to the PCM connector (resistance should be under 1 Ω); also check for shorts to battery positive (should read no continuity)
  7. 7
    Replace the IAT sensor (or MAF/IAT assembly if integrated), clear codes, and perform a test drive covering both cold-start and warm operating conditions to verify the repair

Related powertrain codes

Frequently asked questions

Can I drive with a P0113 code?

Short-term driving is generally possible because most PCMs substitute a default air temperature value. However, in cold weather the substituted value can cause significant fuelling errors, leading to rough running, plug fouling, or a no-start. It is best to diagnose and repair the fault promptly rather than rely on the fail-safe.

Is P0113 always caused by a bad IAT sensor?

Not always. The sensor itself is one possible cause, but an open wire, a corroded connector terminal, or a missing ground are equally common culprits. Always inspect the wiring and connector before replacing the sensor, as these repairs are simpler and cheaper.

What is the difference between P0112 and P0113?

P0112 (circuit low) sets when the IAT signal voltage is abnormally low — indicating a short to ground or a shorted sensor. P0113 (circuit high) sets when the voltage is stuck high — indicating an open circuit, a short to power, or a failed-open sensor. Both codes mean the PCM cannot trust the IAT reading, but they point to opposite electrical fault types.

How do I confirm the IAT sensor is faulty and not the wiring?

Disconnect the sensor connector and briefly jumper the two sensor wires together with the ignition on. If a scan tool shows the temperature reading jump to maximum (or the PCM stores P0112), the circuit wiring to the PCM is intact and the sensor itself is the fault. If there is no change, suspect wiring or connector issues between the sensor and PCM.

Disabling P0113 in software

RaceTune can permanently disable P0113 — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.

Permanent
The monitor is disabled in the ECU itself — not just cleared. It cannot return.
Tailored to your file
Each patch is matched to your specific software version — never a one-size-fits-all file.
Reversible
The original file is always preserved. Reflash the stock to return the ECU to factory state.

Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.

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