P0112: The intake air temperature sensor signal reads too low in voltage, which the computer interprets as extremely hot intake air
Intake air temperature sensor circuit low
Severity: Severity not verified — if the car runs badly, have it inspected
No source we read says how urgent this code is, so we have not set a severity; have it read and checked rather than assuming it is harmless.
P0112 in short
P0112 means the intake air temperature sensor circuit is sending a very low voltage, which the engine computer reads as extremely hot air. A shorted wire, a failed sensor or a poor connection are the usual causes. Check the wiring and connector first, then test the sensor.
The intake air temperature (IAT) sensor tells the engine computer how warm the incoming air is. The computer reads it as a voltage that changes with temperature.
TroubleCodes.net says P0112 sets when the signal drops to a very low voltage (under about 0.1 V), which the computer reads as air hotter than about 149 C. Real intake air is almost never that hot, so the fault is usually in the circuit rather than the air.
Because the Delaware DMV list and TroubleCodes.net both title the code as a low-input IAT circuit fault, the meaning is the same on any make that uses the generic definition.
Most likely causes
These are general causes for this code across vehicles. None is specific to one make or model.
Cause 1: Signal wire shorted to ground, or damaged wiring
Common general cause- Why it ranks here
- TroubleCodes.net lists shorts to ground and rodent or other harness damage; a grounded signal wire gives the very low voltage this code checks for.
- What would change this
- A wire that tests shorted to ground, or a chewed or chafed harness, confirms it. A clean harness lowers it.
Cause 2: Failed or contaminated intake air temperature sensor
Common general cause- Why it ranks here
- The page lists a defective sensor, and one contaminated by a dirty air filter or heavy crankcase blow-by.
- What would change this
- Sensor resistance far from the vehicle's temperature chart confirms it; a sensor that reads in range lowers it.
Cause 3: Corroded connector, poor electrical connection or low battery voltage
Possible — needs testing- Why it ranks here
- Poor connections and low battery voltage are on the same list of causes.
- What would change this
- Corrosion or a loose pin at the connector raises it; a healthy battery and clean pins lower it.
Cause 4: Engine computer fault (uncommon)
Possible — needs testing- Why it ranks here
- The page calls an engine computer fault less common, to be considered only after the sensor and circuit pass.
- What would change this
- Rises only if the 5 V reference and signal are bad at the computer connector with good wiring.
What to test first
Start at step 1. Each result tells you what it means and where to go next.
Step 1: Read the intake air temperature on a scan tool with the engine cold and compare it with the outside temperature.
IfThe reading is far too hot (such as 140 C or more) and does not change
It meansThe signal is low or shorted; inspect the wiring and connector.
IfThe reading is plausible
It meansThe fault may be intermittent; wiggle the harness while watching the reading.
Step 2: With the ignition off, inspect the sensor connector and harness for corrosion, chafing, rodent damage or a pinched wire.
IfDamage or corrosion is found
It meansRepair the wiring or connector.
IfThe wiring looks fine
It meansTest the sensor and circuit.
Step 3: Unplug the sensor and measure its resistance, then check the 5 V reference and signal at the connector with the key on.
Warning:Back-probing a live connector can short the pins and damage the sensor or computer; use the correct probes and keep the key off when connecting.
IfResistance does not match the temperature chart
It meansReplace the sensor.
Points to: Failed or contaminated intake air temperature sensor
IfThe reference is missing or the signal is grounded with a good sensor
It meansTrace the wiring back to the computer.
Symptoms
- Check engine light
- Possible hesitation when the engine is cold
- Possible pinging when hot
- Lower fuel economy
How to fix
Step 1: With the engine off, check that the intake air temperature sensor (or MAF sensor, if the sensor is built in) connector is fully latched.
Step 2: Look along the sensor wiring for chafing or breaks and at the connector for corrosion.
Parts and cost context
- Intake air temperature (IAT) sensor:Often a separate, inexpensive part, but on many engines it is built into the MAF sensor. Confirm the circuit before buying.
Labor varies by vehicle and shop; get a quote before you approve a repair.
Compare used part prices on PartPriceGuideOn your vehicle
ChevroletYour car
1997–2002 · Malibu
Supported by vehicle dataChevrolet bulletin 020603005 covers a Service Engine Soon light with stored codes P0112, P0113, P1111 or P1112. Whether it is still current is not verified.
020603005Status unverified
Chevrolet bulletin: Service Engine Soon light on with stored P0112, P0113, P1111 or P1112
1997–2002malibu · issued · NHTSA 634780
Chevrolet bulletin 020603005 for the 1997-2002 Malibu. The summary says customers may report the Service Engine Soon light on with P0112, P0113, P1111 or P1112 stored. Only the NHTSA summary was read, not the full bulletin; the summary does not give the repair.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
BuickYour car
2004 · Rainier
Supported by vehicle dataBuick bulletin 3192 covers a reduced engine power message or check engine light with any combination of a code list that includes P0112. Whether it is still current is not verified.
3192-buickStatus unverified
Buick bulletin: reduced engine power message or check engine light with a list of codes including P0112
2004rainier · NHTSA 10010867
Buick bulletin 3192 for the 2004 Rainier. The summary says a reduced engine power message and/or check engine light may appear with any combination of a list of codes that includes P0112, and mentions a repeat powertrain control module issue. Only the NHTSA summary was read, not the full bulletin; the summary does not give the repair.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
GMCYour car
2002–2004 · Envoy
Supported by vehicle dataGMC bulletin 3192 covers a reduced engine power message or check engine light with any combination of a code list that includes P0112. Whether it is still current is not verified.
3192-gmcStatus unverified
GMC bulletin: reduced engine power message or check engine light with a list of codes including P0112
2002–2004envoy · NHTSA 10010867
GMC bulletin 3192 for the 2002-2004 Envoy. The summary says a reduced engine power message and/or check engine light may appear with any combination of a list of codes that includes P0112, and mentions a repeat powertrain control module issue. Only the NHTSA summary was read, not the full bulletin; the summary does not give the repair.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
Related codes
No curated relationships for P0112 yet.
All Air metering (MAF, MAP and intake air temperature) codes
P0112 questions
What does P0112 mean?
The intake air temperature sensor circuit is sending a very low voltage, which the engine computer reads as extremely hot air.
Sources and review
- P0112 trouble code
- On-Board Diagnostic Trouble Codes (generic code title list)
- 020603005: Chevrolet bulletin: Service Engine Soon light on with stored P0112, P0113, P1111 or P1112
- 3192: Buick bulletin: reduced engine power message or check engine light with a list of codes including P0112
- 3192: GMC bulletin: reduced engine power message or check engine light with a list of codes including P0112
- Last reviewed
- Written by
- Saurabh K.
- Editorial review
- Pending
- Technician review
- Technician review pending
This page explains what a code usually means; it is not a substitute for a professional inspection. How we source and review · Report an error