P0113 Code: Intake Air Temperature Sensor 1 Circuit High, Explained and Fixed
It's a warm afternoon, the check engine light is on, and your scanner says the air going into the engine is 40 below zero. That reading is your first clue. P0113 means the intake air temperature (IAT) sensor signal is stuck near the top of its voltage range, and the engine computer translates that into air colder than anything the weather could produce.
The good news: P0113 is almost always an electrical problem you can find in your driveway with a scan tool, and the parts involved are usually inexpensive.
P0113 Intake Air Temperature Sensor 1 Circuit High (Bank 1): What It Means
P0113 means the IAT sensor 1 signal voltage is too high, which the engine computer reads as extremely cold air. That's why a scan tool so often shows about −40°F (−40°C) with this code: SAE J1979 starts the intake air temperature scale at −40°C, so a signal pinned at the top of its voltage range lands at the bottom of the temperature scale.
The IAT sensor is a small thermistor whose resistance falls as air gets warmer. The computer sends it a reference voltage and reads what comes back: warm air pulls the signal down, cold air lets it rise. Like every diagnostic trouble code, P0113 names a failed check ("signal voltage too high"), not a failed part.
Tech Note: The "Bank 1" in some code lists isn't tied to a cylinder bank. "Sensor 1" is what matters: the primary IAT, usually in the air box or inside the MAF. Many turbocharged engines add an IAT 2 after the intercooler, which sets its own codes.
What Can Cause a P0113 Code?
Most P0113 codes come from the connector or the wiring, often right after an air filter change. A failed sensor is next, and the computer is rarely at fault. Check in this order:
- Unplugged or loose connector (most common after an air filter change). Air box lids and intake ducts get moved, and the plug gets left half on.
- Corroded or spread terminals (common in wet climates). Corrosion adds resistance, and added resistance raises the signal voltage.
- Open signal or ground wire (watch for rodent damage). A broken circuit reads exactly like freezing air.
- Failed IAT sensor (common once wiring checks out). The thermistor can open internally.
- Engine computer fault (rare). Consider it only after the sensor, wiring and ground all pass.
Can a Dirty Air Filter Cause P0113?
Not directly. A clogged filter restricts airflow, but it doesn't change the IAT circuit voltage, so it won't set P0113 on its own. Where filters do get involved:
- A filter change that left the sensor unplugged or the wiring pinched under the air box lid → very common P0113 trigger.
- An over-oiled aftermarket filter that coats a MAF-mounted IAT element → usually skews airflow readings first, but can contaminate the sensor.
- Water pulled in through a damaged air box → corrosion at the connector over time.
Can I Still Drive With a P0113 Code?
Short answer: yes, for normal driving, but don't put it off for months. When the computer stops trusting the IAT signal, most engines swap in a substitute value and carry on. You may notice harder cold starts, slightly rough running or worse fuel economy, because air temperature helps decide how much fuel to add.
Factory information backs this up: the service information for the 2005 Saab 9-2X 2.5i (Saab WIS) sets P0113 immediately when the fault is recognized and lists erratic idle and poor driving performance as the symptoms.
Red Flag: If P0113 shows up together with other sensor codes, stalling or limp mode, look for a shared problem such as a damaged harness or a ground fault, and have it checked before a long trip.
Can P0113 Cause a Misfire?
Rarely on its own. A wrong air temperature reading shifts the fuel mixture a little, which can make a cold engine stumble, but most engines limit the damage with a backup value. If you also have P0300–P0308, treat them as a separate problem first. Our guide to the P0300 engine code walks through the misfire side.
How Do I Fix Trouble Code P0113?
Check the IAT reading, the connector and the circuit before you buy a sensor. The cheapest fix, a plug pushed back on, turns up early in this sequence.
STEP 1Save the Evidence
Read all codes and save the freeze frame data before clearing anything. Note any other sensor or reference-voltage codes; several at once point to a shared circuit.
STEP 2Check the IAT Reading
- About −40°F with the engine warm → the signal is open or high. Go to Step 3.
- A believable reading that drops out now and then → it's intermittent. Wiggle the harness while watching the graph.
- After an overnight soak, IAT and coolant temperature should read close to each other and to the outside temperature. IAT at −40°F while coolant reads 60°F → circuit problem confirmed. Our guide to reading OBD2 live data shows how to put both on one graph.
STEP 3Find the Sensor
On most engines, IAT sensor 1 is in the air box, the intake duct, or built into the MAF sensor. Match the location to your engine's repair information, especially on turbo engines with a second IAT.
STEP 4Inspect the Connector and Harness
Unplug it and look inside. Green crust, a pushed-back pin or a wire chafed against the air box all count. Reseat the plug until it clicks, clear the code, and recheck the reading.
STEP 5Test the Circuit
- Reference: key on, sensor unplugged, the signal wire should show the reference voltage set by your service manual.
- Ground: resistance to engine ground should be very low. The Saab procedure above, for example, calls for less than 5 Ω.
- Sensor: if reference and ground pass but the reading stays at −40°F with the sensor plugged in, the sensor is the likely culprit.
STEP 6Repair, Clear and Verify
Repair the wiring or replace the sensor. If it shares a housing with the MAF, replace the assembly with a quality part matched to your engine. Then follow our steps to reset the check engine light with an OBDII scanner, and confirm the IAT reading tracks outside temperature on the next cold start.
Rule of thumb: If a brand-new sensor still reads −40°F, the part isn't the problem. The wiring is.
What a P0113 Repair Costs
Fixing P0113 usually costs $20–$295, from reseating a connector to repairing a wire. A new sensor runs $40–$145, or $115–$435 when the IAT is built into the MAF. No national repair survey tracks P0113 by itself, so these are our estimates for U.S. independent shops at an assumed $110–$170 per labor hour:
| Repair | Part Cost | Labor Time | Estimated Total |
|---|---|---|---|
| Diagnosis | None | 0.5–1 hr | $55–$170 |
| Reconnect or clean connector | None | 0.2–0.5 hr | $20–$85 |
| Connector pigtail or wire repair | $15–$40 | 0.5–1.5 hr | $70–$295 |
| Standalone IAT sensor | $15–$60 | 0.2–0.5 hr | $40–$145 |
| MAF sensor with built-in IAT | $80–$350 | 0.3–0.5 hr | $115–$435 |
Bottom line: the cheapest fix on this list is a connector you push back on. A scanner that shows the IAT reading tells you in minutes whether that's all you need, which is exactly what a car scanner actually puts back in your pocket.
LAUNCH Scanners for Diagnosing P0113
P0113 diagnosis starts with the IAT reading in live data, ideally next to coolant temperature, and all three of these LAUNCH scanners show it: the LAUNCH CRP129X V3.0 for a budget check, the LAUNCH X431 CRP919X when you also want freeze frame and an I/M readiness check, and the LAUNCH X431 CRP919X BT for MAF-housed or second IAT sensors.
| What You Need to Do | Features Required | Fits Best |
|---|---|---|
| Confirm the code and the −40°F reading | Engine codes, IAT and coolant graph | CRP129X V3.0 |
| Full check plus post-repair readiness | All-system scan, freeze frame, I/M readiness, 8-in-1 graph | CRP919X |
| MAF-housed or second IAT sensors | Manufacturer-level engine data, Bluetooth VCI | CRP919X BT |
LAUNCH CRP129X V3.0: Budget Confirmation
- Covers: it pulls the P0113 code and plots IAT next to coolant temperature on one screen, on supported vehicles. It also checks transmission, ABS and SRS.
- Who it fits: budget DIY work; software updates stay free for life.
LAUNCH X431 CRP919X: Full Check and Readiness
- Covers: it adds an all-system scan, freeze frame, an I/M readiness check and 8-in-1 live data graphs on a 7-inch screen.
- Who it fits: serious DIYers who want the whole check in one handheld; updates are free for the first 2 years.
LAUNCH X431 CRP919X BT: For MAF-Housed and Second IAT Sensors
- Covers: it reads manufacturer-level engine data through a Bluetooth VCI and its own 7-inch tablet, with freeze frame and active tests on supported vehicles.
- Who it fits: home mechanics who go past code reading, and small shops; 2-year free update period.
Keeping P0113 From Coming Back
- Check the plug after every air filter change. It's the single easiest way to prevent this code.
- Route the harness away from the air box lid clips so it can't get pinched.
- Go easy on oiled filters. Follow the oiling instructions so excess oil doesn't reach the sensor.
- Seal a cracked air box before water reaches the connector.
P0113 is a signal problem, and the signal tells you where to look.
Read the IAT value, check the plug, test the circuit, and only then buy parts. If the same "circuit high" logic sounds familiar, our P0193 fuel rail pressure sensor guide applies it to the fuel system. Still deciding on a tool? Our guide to professional vs. DIY diagnostic scan tools helps you choose.
FAQ
What can cause a P0113 code?
Usually an unplugged or corroded IAT connector, a broken signal or ground wire, or a failed sensor. An engine computer fault is rare.
How do I fix trouble code P0113?
Check the IAT reading with a scanner, inspect and reseat the connector, test the reference and ground, then repair the wiring or replace the sensor. Clear the code and confirm the reading is believable.
Can a dirty air filter cause P0113?
Not by itself. But a filter change that leaves the sensor unplugged or pinches its wiring is one of the most common triggers.
Can I still drive with a P0113 code?
Usually yes. The engine runs on a backup air temperature value, though cold starts and fuel economy may suffer. Fix it soon.
Can P0113 cause a misfire?
Rarely. It can make a cold engine run a little rough, but misfire codes alongside P0113 usually have a separate cause.
