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

P0113 on a Cadillac is "Intake Air Temperature (IAT) Sensor Circuit High." For most of Cadillac's history that meant the IAT signal had gone to the top of its range — which the engine computer reads as impossibly cold air, the classic sign of an open circuit or unplugged sensor. But GM has defined this one code three different ways on Cadillac engines, and on the 2019-era ATS, CTS, CT6, XT4, XT5, XTS and Escalade, GM's tables define it the opposite way: a sensor reporting an impossibly hot temperature over a digital link. GM's only Cadillac bulletin for P0113 fixes it without a part — by reseating a connector.

What Does P0113 Mean on a Cadillac?

The intake air temperature sensor tells the engine control module (ECM) how warm the incoming air is. Cold air is denser, so the ECM uses IAT for fuel and spark corrections, cold-start calculations and as a cross-check on other sensors. GM's airflow diagnostics, for example, only run when intake air temperature is inside a set window.

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 gives low resistance and low voltage; cold air gives high resistance and high voltage. If the circuit opens, resistance becomes effectively infinite, the voltage goes to the top of the range, and the ECM reads arctic air. That is the classic P0113.

On many Cadillacs built since the early 2010s, the IAT is not a separate part. It is built into the MAF sensor housing, alongside humidity and barometric pressure sensing on some engines. GM's 2013–2014 PI for the ATS, CTS, SRX and XTS V6 groups P0113 with exactly those other sensors.

Three Versions of the Same Code

GM's own diagnostic tables show how the definition has changed on Cadillac engines:

The first two are the same idea — voltage or resistance too high, read as extreme cold. The third is new. On a LIN-type MAF, the sensor converts temperature itself and sends a digital number. If that number is above 150 °C — hotter than any intake air could be — the ECM sets P0113. Those two 2019 table groups list P0113 only in its LIN form, which suggests the engines they cover use a LIN MAF, but GM does not say so engine by engine, and we could not confirm it for every model. A dealer's service information will tell you for your VIN.

There is even a fourth test. GM's 2019 table for the 4.2L twin turbo (LTA) in the CT6-V describes P0113 as a physical range check that fails when the filtered intake air temperature is above 122.76 °C for 2 seconds, as a two-trip code.

Which Cadillacs Set P0113

GM-designed Cadillac engines from the OBD-II era list P0113 in GM's tables: the Northstar V8s, the 3.2L and 3.6L V6s, the 2.8T and 3.0L V6s, the 2.0T, 2.5L and 2.7L four-cylinders, the turbo V6s, and the Escalade and V-series V8s.

The exception is the Catera. GM's 1997–2000 tables for the Opel-built 3.0L V6 report intake air temperature faults as P0110, a single code with a high range check (above roughly 140 °C) and a low range check (below about −43 °C). A Catera will not normally show P0113.

Many turbocharged and supercharged Cadillacs measure intake temperature in more than one place, so you may also see second- or third-sensor codes such as P0097 or P00EA. P0113 is the sensor at the MAF.

The only GM bulletin we found naming P0113 on a Cadillac is PI1009, for the 2013–2014 ATS, CTS, SRX and XTS.

GM's ATS, CTS, SRX and XTS PI

PI1009 (June 2013) covers the 2013–2014 Cadillac ATS, CTS, SRX and XTS with the 3.0L and 3.6L V6 (RPO LFW, LLT or LFX), along with their Buick, Chevrolet and GMC cousins. The complaint is a service engine soon light with any of P0097, P00F4, P0113, P2229 and/or P0102.

That list tells the story. Each of those codes belongs to a sensor in the multifunction MAF housing — intake temperature, humidity, barometric pressure and the MAF itself. 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 — potentially on the first trip on a late-1990s Northstar
• Often no noticeable driveability change, because the ECM substitutes a default temperature
• 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 — around −40 on a thermistor circuit, or an impossible high value on a LIN MAF

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 near −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. On a thermistor circuit, unplug and test. Briefly jumpering the 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, and on a LIN MAF its power, ground and data wire.
6. Replace the sensor or MAF assembly only once the circuit is proven good.
7. Clear and drive. Most modern Cadillac tables list it as a two-trip code.

Parts and Cost

Order by VIN. Integrated Cadillac MAF sensors differ in which functions they include and in how they talk to the ECM.

GM Documents That Name P0113 on Cadillacs

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 many recent Cadillacs it is inside the MAF housing and comes as one assembly.
• "High means hot." On a thermistor circuit, "circuit high" reads as extreme cold. Only GM's LIN MAF version — and the CT6-V's separate test — define P0113 as an erroneously high temperature.
• "Replace the sensor." GM's only Cadillac bulletin for this code fixes it by reseating the connector.
• "Every Cadillac uses P0113." The Catera reports intake temperature faults as P0110.
• "It's always a one-trip code." The late-1990s Northstar table makes it one trip; most modern Cadillac tables make it two.

Frequently Asked Questions

Is P0113 serious?

Usually not urgent. The ECM substitutes a default temperature, and many cars drive normally. Cold starts and fuel economy can suffer, and the car will fail an emissions inspection with the light on, so fix it soon.

Can an air filter change cause P0113?

Yes. GM's PI1009 says unplugging the MAF with the ignition on — during air filter or A/C service — can set P0113 and its companion codes on 2013–2014 ATS, CTS, SRX and XTS V6 models. Reseat the connector and clear the codes. Our Cadillac air filter fitment guide covers the filter itself.

What should IAT read on a cold engine?

After an overnight soak, close to the outside air temperature and to coolant temperature. A reading around −40 suggests an open circuit; a reading of 150 °C or more on a cold car suggests a LIN sensor reporting a bad value.

Do I need a new MAF sensor for P0113?

Only if the IAT is integrated into the MAF on your engine and the circuit has tested good. Check the connector and wiring first, and order by VIN.

Why does my Catera show P0110 instead?

GM's tables for the Opel-built 3.0L Catera use P0110 for intake air temperature faults, with both the high and low range checks under one code.

Can P0113 cause other problems?

It can affect cold-start fueling and disable other diagnostics that need a valid intake temperature. That is one reason the light should not be ignored.