P0113: P0113 Diagnostic Guide

What this code means

P0113 often means the PCM is seeing an intake air temperature sensor signal that is higher than expected for its self-check logic.

What the vehicle may do

The vehicle may turn on the check engine light.
It can sometimes have driveability, fueling, or starting complaints.
It may also appear to run normally while the fault is stored.

Possible fault areas

A possible IAT sensor circuit concern may be involved.
The IAT sensor may be involved.
A PCM-related concern is possible after the circuit and sensor checks are proven out.

Diagnostic path

What P0113 is telling you

On this 2015-2025 Ford F-150 with the 2.7 EcoBoost, P0113 is an intake air temperature signal-high fault. In plain language, the PCM is seeing the IAT sensor signal higher than its self-test maximum. The truck may have a check engine light, and it can have driveability or fueling complaints depending on when the fault shows up, but the diagnostic path here is electrical first. The broad possible fault areas are the IAT sensor circuit, the IAT sensor itself, and, after the circuit and sensor checks are proven out, the PCM. Treat this like technician-level circuit testing: start with the basic system checks, then follow a structured diagnostic approach instead of jumping straight to parts.

Start the target-code path

Begin by confirming the code picture. If other codes are present, check what they mean first so you do not chase the wrong branch. For the P0113 path, continue into the IAT circuit checks. If P0113 is not present and you are working from a symptom instead, use the symptom direction rather than forcing this pinpoint path.

Check the IAT circuit for an open

With the ignition off, disconnect the PCM connector. On the 2.7L EcoBoost, disconnect the IAT sensor connector and only measure the circuits that apply to this vehicle. Check resistance between C129 Pin 1 and C1232B Pin 35, and between C129 Pin 2 and C1232B Pin 40. Both readings need to be less than 5 ohms. If they are, move on to the short checks. If they are not less than 5 ohms, repair the open circuit, clear the PCM DTCs, and repeat the self-test.

Check for shorts before blaming the sensor

Next is the short-to-ground check on the IAT circuit. The test point shown clearly for this engine is C129 Pin 1, but the other meter-lead location is not clear here. Do not guess at that connection; stop and confirm the correct circuit point before testing. The decision point is still clear: resistance greater than 10000 Ω lets you continue to the short-to-voltage check. If it is not greater than 10000 Ω, repair the short circuit, clear the PCM DTCs, and repeat the self-test. Then turn the ignition on for the short-to-voltage check. Again, C129 Pin 1 is the clear IAT-side test point, but the other lead location is not clear here, so confirm it before applying the test. If any voltage is present, repair the short circuit, clear the PCM DTCs, and repeat the self-test. If no voltage is present, continue to the intermittent check.

Work the harness and watch the PID

For the intermittent check, turn the ignition off, reconnect the PCM connector, and reconnect the IAT sensor connector. Turn the ignition on, access the PCM, and monitor the IAT (Deg C) PID, IAT11 (Deg C) PID, and IAT21 (Deg C) PID. Not every PID may be available on every vehicle. While watching the PID, wiggle, shake, and bend small sections of the harness from the sensor back toward the PCM. Lightly tap near the sensor housing and move the connector to simulate road shock. If the IAT PID reading changes, repair as necessary, reset the keep alive memory, and repeat the self-test. If the reading does not change, continue to the circuit voltage cycling check.

Simulate the circuit response

Now check whether the PCM can see the IAT circuit change state. With the ignition off, disconnect the IAT sensor connector. Turn the ignition on, access the PCM, monitor the IAT1_V (V) PID, and record the IAT PID value. The next step uses a 5 amp fused jumper wire from C129 Pin 1 to the second lead location, but that second jumper point is not clear here. Confirm the correct second connection before installing the jumper. Once the jumper is connected, the IAT PID should change from greater than 3.0 volts to less than 0.20 volt. If it does, install a new IAT sensor, reset the keep alive memory, and repeat the self-test. If it does not make that voltage change, move on to the PCM connector and operation check.

Use the temperature correlation branch when the code picture calls for it

The same IAT pinpoint test also has a temperature-correlation branch that feeds into the final PCM check. Use it when the initial code picture points that way, rather than forcing it into every P0113-only diagnosis. The temperature values need to be checked with the engine at ambient temperature. If needed, cold soak the engine for a minimum of 8 hours while it is not in direct sunlight. With the ignition off, connect the IAT sensor connector. Turn the ignition on, access the PCM, and compare the available ambient, charge-air, coolant, cylinder-head, and IAT temperature PIDs. Not every PID may be available on every vehicle. The readings should be within 17°C (30°F) of each other. If they are within that range, continue to the PCM operation check. If they are not, install the sensor in question — IAT, MAF/IAT, or MAPT — reset the keep alive memory, and repeat the self-test.

PCM connector check and repair verification

Before condemning the PCM, disconnect all PCM connectors and inspect them for pushed-out pins and corrosion. Reconnect all of the PCM connectors and make sure they seat correctly, then verify whether the concern is still present. If the concern is still present after the circuit, intermittent, sensor-response, and connector checks, install a new Powertrain Control Module. If the concern is gone, the system is operating correctly at this time, and the fault may have been caused by a loose or corroded connector. After any repair, keep verification separate from testing: clear the PCM DTCs, reset keep alive memory when the path calls for it, repeat the self-test, and confirm P0113 stays gone. Takeaway: prove the wiring first, use the PID response to separate sensor from circuit, and only move to the PCM after the connector check supports it. For more diagnostic training, visit stepdiagnostics.com.