P0113 Code on a Buick: Intake Air Temperature Sensor Circuit High (Buick Guide)

P0113 on a Buick is "Intake Air Temperature (IAT) Sensor Circuit High." On older Buicks that means the IAT signal voltage went to the top of its range — which the computer reads as impossibly cold air, the classic sign of an open circuit or unplugged sensor. On most recent Buicks the IAT is not a separate part at all: it lives inside the MAF sensor housing. And on the newest GM engines whose MAF reports over a digital LIN link, GM redefines P0113 as an erroneously high temperature — the opposite of the old meaning. Knowing which kind your Buick has decides what you test.

What Does P0113 Mean on a Buick?

The intake air temperature sensor tells the ECM how warm the incoming air is. Colder air is denser, so the ECM uses IAT for fuel and spark corrections, for cold-start calculations and as a cross-check on other sensors — GM's P0128 thermostat test, for example, uses intake air temperature as one of its inputs.

A traditional IAT sensor is a thermistor: its resistance falls as temperature rises. The ECM feeds it a reference voltage through a resistor and reads the voltage on the signal wire. Hot air means low resistance and low voltage; cold air means high resistance and high voltage. If the circuit opens, resistance is effectively infinite, the voltage goes to the top of the range, and the ECM reads arctic air.

That is the classic P0113: a signal so high it can only be electrical.

Three Versions of the Same Code

GM's own diagnostic tables show how the definition has changed across Buick generations:

The first two are the same idea — resistance or voltage too high, read as extreme cold. The third is new: on a LIN-type MAF, the sensor does its own temperature conversion and sends a digital number. If that number is above 150 °C — hotter than any intake air — the ECM sets P0113.

GM's documents do not list which Buick engines use the LIN version, and we could not confirm it from GM sources. Your service information or a dealer can tell you for your VIN.

All three are two-trip (Type B) codes in GM's tables.

Which Buicks Set P0113

Every Buick from the OBD-II era has an IAT sensor and can set P0113. Where it lives depends on the generation:

• 3800 V6 Buicks (Regal, LeSabre, Park Avenue, LaCrosse, Allure and Lucerne) — GM's 1997–2006 parameter tables all list P0113 for the 3.8L.
• 3.6L V6 Enclave, LaCrosse and Regal — on 2013–2014 models GM's PI1009 shows the IAT is part of a multifunction MAF that also measures humidity and a second intake temperature.
• Ecotec four-cylinders and turbo Buicks — Regal, Verano, Encore, Envision, Encore GX, Envista. Many newer engines measure intake temperature in more than one place, which is why GM also uses IAT sensor 2 codes such as P0097 — the 3.6L PI below lists both. P0113 is IAT sensor 1.

The only GM bulletin we found naming P0113 on a Buick is PI1009, for the 2013–2014 Enclave and LaCrosse.

GM's Enclave and LaCrosse PI

PI1009 (June 2013) covers 2013–2014 Enclave and LaCrosse with the 3.6L (LLT/LFX), plus the Chevrolet, GMC and Cadillac cousins. The complaint is a service engine soon light with any of P0097, P00F4, P0113, P2229 and/or P0102.

That list is telling: P0097 is a second IAT circuit, P00F4 is the humidity sensor, P2229 is barometric pressure and P0102 is the MAF itself — every sensor in the multifunction housing. GM's explanation is that the codes "may be caused by disconnecting the mass air flow (MAF) sensor with the ignition key on and/or the engine running" during service — topping up A/C refrigerant, changing the air filter, or working on other underhood parts.

GM's fix is not a part. Recheck the connector for proper click engagement and clear all the codes. If P0113 turned up right after someone had the hood open, start there.

Symptoms of P0113

• Check engine light
• Often no noticeable driveability change — the ECM substitutes a default value
• Possible hard starting or rough running when cold, since cold-start fueling uses intake temperature
• Companion codes from the same MAF housing: P0097, P00F4, P2229, P0102
• Scan tool showing intake air temperature stuck at an extreme, such as −40 °F/°C

Causes and How to Confirm Each

How Is P0113 Diagnosed?

1. Read IAT on a scan tool after the car has sat overnight. Cold-soaked, IAT should be close to coolant temperature and outside air temperature. A reading of −40 points to an open circuit; an impossible high reading points to a LIN sensor fault.
2. Note the companion codes. A cluster from the same MAF housing points at its connector or shared wiring.
3. Reseat the connector and clear the codes, as GM's PI1009 instructs.
4. Unplug and test. On a thermistor-type circuit, briefly jumpering signal to low reference should make the scan reading jump to a very hot value — that proves the wiring and ECM, leaving the sensor.
5. Check the low reference and signal circuits back to the ECM.
6. Replace the sensor or MAF assembly only once the circuit is proven good.
7. Clear and drive twice. It is a two-trip code in GM's tables.

Parts and Cost

Order by VIN. Integrated MAF sensors differ in which functions they include.

GM Documents That Name P0113 on Buicks

Have a dealer check your VIN against current bulletins and campaigns rather than relying on any article, including this one.

What Other P0113 Pages Get Wrong

• "The IAT sensor is in the air box — just swap it." On most recent Buicks it is inside the MAF housing and comes as one assembly.
• "High means hot." On a thermistor-type circuit, "circuit high" reads as extreme cold. Only GM's LIN MAF version defines P0113 as an erroneously high temperature.
• Replacing parts after an air filter change. GM's PI for the Enclave and LaCrosse says the codes are often caused by unplugging the MAF with the key on.
• Ignoring the companion codes. P0113 with P0097, P00F4 and P2229 is one connector, not four bad sensors.
• Calling it harmless. It rarely affects driving, but IAT feeds other GM diagnostics — including the P0128 thermostat test — and can stop monitors from running.

For how the MAF and its built-in sensors fit with MAP and oxygen sensors, see GM MAF vs MAP vs O2 sensor: which to replace.

Frequently Asked Questions

Can I drive with P0113?

Usually yes. The ECM uses a default air temperature and most Buicks drive normally. Fix it before an emissions test, because other monitors may not run with it set.

Where is the IAT sensor on my Buick?

On older 3800 Buicks it is a separate plug-in sensor in the intake duct or air box. On most recent Buicks it is built into the MAF sensor between the air box and the throttle body. Confirm in the service information for your VIN.

Why does my scanner show −40 degrees intake air temperature?

That is the classic reading of an open IAT circuit — an unplugged connector, broken wire or failed sensor. The ECM sees infinite resistance and reports the coldest value it can.

Can P0113 cause hard starting?

It can make cold starts less smooth on some engines, because the ECM uses intake temperature in its starting calculations. Many owners notice nothing.

Does P0113 mean I need a new MAF sensor?

Not until the connector and wiring check out. GM's own Buick PI for this code fixes it by reseating the connector.

Is P0113 the same as P0112?

No. P0112 is IAT circuit low — usually a short to ground, read as extreme heat. P0113 is circuit high, usually an open.