P1117 — Intake Air Temperature (IAT) Sensor Circuit Intermittent Low Voltage

OBD2 code P1117 flags a problem with the throttle and intake air metering (intake air temperature (IAT) sensor circuit intermittent low voltage). Short, gentle driving to a shop is usually possible. Common culprits: faulty throttle position sensor or pedal sensor, intake air leaks after the MAF sensor, wiring or connector faults in the throttle circuit.

For Ford vehicles

engine coolant temperature sensor – intermittent fault

powertrain (engine/transmission)

Is it safe to drive?

Drive with caution Drive with caution. Many throttle faults put the car into limp mode with limited power — enough to reach a shop, not for highway trips. If the engine stalls or the pedal stops responding, do not drive.

How to diagnose with an OBD scanner

Read the code and freeze frame Connect an OBD2 scanner, confirm P1117 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
Check for companion codes and TSBs Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many P0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
Inspect wiring and connectors Visually inspect the wiring harness and connectors related to the throttle and intake air metering for damage, corrosion, chafing or poor contact.
Subsystem check Inspect and clean the throttle body; check that the plate moves freely.
Subsystem check Watch throttle position and MAF/MAP readings in live data while pressing the pedal — values should change smoothly.
Verify the repair Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm P1117 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for P1117 (parts and labor, USD, independent shop rates): Clean the throttle body: $80–$200; Replace the MAF or MAP sensor: $150–$400; Replace the throttle body assembly: $250–$700. Overall, fixing P1117 usually costs between $80 and $700. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.

Common questions

How much does it cost to fix P1117?

Clean the throttle body — $80–$200; Replace the MAF or MAP sensor — $150–$400; Replace the throttle body assembly — $250–$700. Exact cost depends on the root cause, your vehicle and local labor rates — a proper diagnosis is the cheapest first step.

Will P1117 clear itself?

Sometimes P1117 clears after a few drive cycles if the fault was intermittent — for example a loose connector or a tank of bad fuel. The underlying cause usually remains, so the code tends to return. Clear it once; if it comes back, diagnose rather than erase it repeatedly.

What is the most common cause of P1117?

The most common causes are: faulty throttle position sensor or pedal sensor, intake air leaks after the MAF sensor, wiring or connector faults in the throttle circuit.

How do I diagnose P1117 myself?

Start with a scan: confirm P1117, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the throttle and intake air metering, and verify the suspect component against live data before buying parts.

What does OBD2 code P1117 mean?

When your scanner pulls a P1117 code, it means the engine control unit has detected that the Intake Air Temperature sensor circuit is behaving erratically — specifically dropping to a low voltage intermittently. This isn't a one-time electrical hiccup that the computer will ignore. The module needs to see this fault pattern repeat under specific operating conditions before it decides to illuminate your Check Engine light and store the code.

The IAT sensor plays a straightforward but critical role: it tells your ECU how warm or cold the incoming intake air is, which affects fuel mixture calculations, ignition timing, and idle quality. When that signal starts flickering or dropping unexpectedly, the computer loses reliable data about what it's actually breathing into the cylinders. P1117 is the ECU's way of saying it caught this intermittent problem happening repeatedly, and the freeze frame data stored alongside the code gives you a snapshot of engine load, RPM, coolant temperature, and vehicle speed at the exact moment the fault was logged.

Understanding why P1117 triggers matters for effective diagnosis. The code won't set from a single bad reading — the powertrain control module watches for a pattern. This means the underlying issue can be subtle: a wire that's almost broken, a connector with corrosion that only acts up when things warm up, or a sensor that's mechanically intact but electrically intermittent.

Symptoms of P1117

The Check Engine light stays on or flickers
Throttle response feels sluggish or unpredictable
Engine stalls when decelerating or coming to a stop
Idle runs rough, bounces, or sits higher than normal
Vehicle enters limp-home mode with noticeably reduced power output
Inconsistent performance under varying temperature conditions

Common Causes

Most P1117 faults trace back to a handful of sources, ranked by how frequently they appear:

Loose, corroded, or damaged wiring connectors in the IAT or throttle circuit
Faulty throttle position sensor or accelerator pedal position sensor
Contaminated or worn MAF (Mass Air Flow) or MAP (Manifold Absolute Pressure) sensor
Intake air leaks located downstream of the MAF sensor
Failed IAT sensor itself (though less common as a standalone issue)
Poor ground connection affecting the sensor circuit

How to Diagnose P1117

Working through P1117 systematically keeps you from throwing parts at the problem:

Confirm the code with an OBD2 scanner, save the freeze frame data, and note any related codes. That freeze frame is your roadmap — it tells you exactly what conditions triggered the fault.
Check for manufacturer technical service bulletins (TSB) specific to your vehicle make and model. Many P0xxx codes have known factory fixes, software updates, or service campaigns. Search by VIN on the manufacturer's site or NHTSA.gov.
Perform a thorough visual inspection of the wiring harness and connectors feeding the IAT sensor and throttle body. Look for chafed wires, bent pins, moisture intrusion, or corrosion that could cause intermittent contact.
Test the throttle body's range of motion — the plate should move freely without binding. Carbon buildup is a common culprit that can affect both mechanical operation and sensor readings.
Monitor live data from the throttle position sensor, MAF sensor, and IAT sensor while gently operating the accelerator. All values should change smoothly and responsively. Erratic jumps or flatlines point toward the problem area.
Clear the code, complete a drive cycle that reproduces the freeze frame conditions (same load, speed, and temperature), and verify that P1117 does not return.

Repair Options and Costs

Address the simplest and cheapest possibilities before committing to major repairs:

Throttle body cleaning: $80–$200 (parts and labor)
MAF or MAP sensor replacement: $150–$400 (parts and labor)
Throttle body assembly replacement: $250–$700 (parts and labor)

The total bill for fixing P1117 typically lands between $80 and $700 depending on what component is actually at fault. An accurate diagnosis before purchasing parts will save you money in the long run — the most expensive repair scenario is rarely the first place you should look.

Driving Safety Verdict

Severity level: Caution. While your vehicle may still run, P1117 can trigger limp-home mode, which severely limits engine power. This reduced-power state is designed to get you off the road safely, not to serve as a long-term solution. If your car stalls unexpectedly or the accelerator pedal becomes unresponsive, stop driving immediately and have it towed. Under no circumstances should you attempt highway driving or aggressive maneuvers with an active throttle fault.