The OBD2 code P0110 signifies an issue within the Intake Air Temperature (IAT) sensor circuit. This sensor measures the temperature of the air entering the engine and feeds data to the vehicle’s computer to optimize the air-fuel mixture. A malfunction in this circuit can lead to poor performance, increased emissions, or difficulty in starting the engine.
P0110 quick overview
| Meaning | P0110: Intake Air Temperature Sensor Circuit Malfunction |
| Is it serious? | Yes, this code can lead to engine performance issues and should be addressed. |
| Possible causes | – Faulty IAT sensor – Damaged wiring or connectors – Poor electrical connection – Faulty Engine Control Module (ECM) |
| How to diagnose? | Inspect the IAT sensor and its connector for damage or corrosion. Check the wiring for shorts, breaks, or burns approximately one foot from the sensor. Test the IAT sensor’s resistance and compare it with the manufacturer’s specifications. Verify proper grounding of the negative battery cable and body ground. Consider checking the engine’s computer (ECM) if other steps do not resolve the issue. |
P0110 Meaning
When the P0110 code appears, it means the car’s computer isn’t getting accurate air temperature readings, which can mess up the fuel mix. Think of it like baking without knowing if your ingredients are at the right temperature.
The engine might run rough, use more gas, or even have trouble starting. Mechanics often look at the sensor itself, the wires connected to it, and the car’s computer to fix the problem.
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How to fix P0110 – learn from mechanics
I looked into P0110 service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics. I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.
Case #1: Nissan
Vehicle Information 1998 Nissan Maxima GLE 3.0L
Issue + Repair History
- MIL lamp on with codes PO325 (knock sensor 1 circuit) and PO110 (IAT circuit)
- Black wire to the IAT sensor found melted, causing erroneous temperature readings
- Repaired damaged wires approximately one foot from the sensor
- Despite repairs, MIL lamp persisted
Other OBD2 Codes + Test Results
- No other OBD2 codes present
- IAT sensor ohms within normal range after repair
- No issues detected with the knock sensor circuit
Mechanic Suggestions
- Check for additional damage or shorts in the wiring harness
- Verify proper grounding of the negative battery cable and body ground
- Inspect for any signs of attempted splicing or tampering with wiring by previous users of the vehicle
- Consider installing additional grounding wires as a preventive measure
Final Fix
- Discovered cut end of the negative battery cable with a universal end installed, leaving the cable short and causing a disconnected body ground eyelet
- Installed an additional ground wire from the battery negative to the body
- Repaired negative battery cable and ensured proper grounding
- MIL lamp stays off after repair, indicating successful resolution of the issue
Case #2: Toyota
Vehicle Information 2002 Toyota Tundra 4.7L
Issue + Repair History
- Vehicle experiencing stalling issues
- MAF sensor registering low idle (2.5 grams per second; should be 4 to 7 grams per second)
- Error code for intake air temperature circuit fault (P110)
- Replaced MAF sensor with new one, but stalling issue persisted
- Vehicle runs fine with foot on the gas but will not idle on its own
Other OBD2 Codes + Test Results
- Error codes: P0100 (MAF/VAF circuit fault), P0110 (intake air circuit fault)
Mechanic Suggestions
- Clean throttle plate and throttle body housing
- Perform top engine clean with throttle body cleaning
- Clear learned PCM values by disconnecting the negative battery cable and shorting it to the positive cable end for several minutes
- Check for vacuum leaks and air inlet tube leaks
- Test operation of idle up valve
- Clean or replace the idle air control (IAC) motor
Final Fix
- Cleaned throttle plate and housing, which resolved stalling issue
- No further stalling was observed after cleaning
Case #3: Hyundai
Vehicle Information 1996 Hyundai Sonata GL 2.0L
Issue + Repair History
- Vehicle experienced a no-start problem
- Engine would only run with foot on gas pedal, RPM limited to 450
- MAF/IAT code detected, MAF sensor replaced
- PCM replaced due to lack of readings for O2 sensors and crank sensor
- Engine still would not idle normally or rev up when gas pedal depressed
Other OBD2 Codes + Test Results
- Error code: P0110 (IAT at -40 deg.)
- Fuel pressure: 49 psi
- Compression: 125 to 145 psi in all cylinders
Mechanic Suggestions
- Check cam timing and condition of catalytic converter
- Perform exhaust back pressure test to check for blocked converter
- Ensure timing belt condition and timing of camshafts are correct
- Consider checking for clogged catalytic converter by disconnecting exhaust at manifold and attempting to rev the engine
Final Fix
- Discovered PCM was not allowing fuel injectors to pulse
- Injectors found to be clogged with rust, not detected by injector flow balance test
- Removed injection system and pulse-tested injectors to confirm no fuel coming out while watching pulse width
- Cleaning or replacing injectors resolved the issue of engine not idling or revving up
How to diagnose P0110
I made you an overview of solving this DTC, based on all the advice that was suggested by certified mechanics to address this issue in previously mentioned service cases.
| Diagnostic Step | Brief Explanation |
|---|---|
| Inspect IAT sensor and connector | Look for any visible damage or corrosion that could disrupt the sensor’s function. |
| Check wiring for damage | Examine the wires near the IAT sensor for signs of wear, burns, or breaks. |
| Test IAT sensor resistance | Measure the sensor’s resistance to ensure it falls within the expected range. |
| Verify proper grounding | Ensure the negative battery cable and body ground are correctly connected and not damaged. |
| Clean throttle plate and housing (if applicable) | Remove any buildup that could be affecting airflow and sensor readings. |
| Check for vacuum leaks | A vacuum leak could cause incorrect air readings and should be addressed. |
| Perform top engine clean | Cleaning the top engine area can sometimes resolve issues causing the P0110 code. |
| Consider ECM check | If other steps fail, the issue might lie within the car’s computer system and needs professional diagnosis. |
Handling a P0110 code involves a thorough check of the IAT sensor, its wiring, and the vehicle’s computer system. Based on real service cases, fixes have ranged from simple wiring repairs to more complex solutions like cleaning or replacing parts of the fuel injection system. Given the potential complexity, seeking professional assistance is advisable for diagnosing and fixing issues related to this code.
Car Diagnostics Training
- Car Electrical basics
- OBD-II scanner basics
- How to use an OBD reader
- Introduction to a Bi-directional Scan tool
- OBD scanner buyer’s guide + discounts
I test OBD-II scanners and make DIY Engine diagnostics guides to help you solve your car problems without having to depend on the mechanic. A lot of them will try to scam you or are just no help at all. About Juraj Lukacko