Faulty engine coolant temperature (ECT) sensor 2, which may be biased or slow to respond.; Faulty ambient air temperature (AAT) sensor, often due to contamination or damage.; Wiring issues such as an open circuit, short to ground, or high resistance in the ECT2 or AAT sensor circuits.; Corroded or loose electrical connectors at either sensor or at the PCM.; A PCM software calibration issue that misinterprets the sensor signals.; Extreme ambient conditions combined with a cold soak that falls outside the correlation window, though this is rare.; A stuck-open thermostat that prevents the engine from reaching normal operating temperature, affecting ECT2 readings.

DTC codes / P01xx · Fuel and air metering / P011F

P011FEngine Coolant Temperature 2 / Ambient Air Temperature Correlation

P011F indicates that the powertrain control module (PCM) has detected an implausible relationship between the engine coolant temperature (ECT) sensor 2 and the ambient air temperature (AAT) sensor. The PCM expects these two temperatures to be within a certain range of each other after a cold soak, and it sets this code when the correlation falls outside that expected window.

SystemPowertrain

Code typeGeneric (all makes)

SeverityLow

Fix difficultyIntermediate

AreaFuel and air metering

Symptoms you may notice

Illumination of the malfunction indicator lamp (MIL) on the dashboard.
Often no symptoms besides the warning light, especially if the fault is intermittent.
Poor fuel economy or slightly rough running when the engine is cold.
Incorrect temperature gauge readings or a gauge that behaves erratically.
Possible hard starting or stalling in extreme cases if the PCM mis-fuels based on faulty temperature data.
Remote start or climate control systems may not function correctly because they rely on ambient temperature data.

Common causes, most likely first

Faulty engine coolant temperature (ECT) sensor 2, which may be biased or slow to respond.
Faulty ambient air temperature (AAT) sensor, often due to contamination or damage.
Wiring issues such as an open circuit, short to ground, or high resistance in the ECT2 or AAT sensor circuits.
Corroded or loose electrical connectors at either sensor or at the PCM.
A PCM software calibration issue that misinterprets the sensor signals.
Extreme ambient conditions combined with a cold soak that falls outside the correlation window, though this is rare.
A stuck-open thermostat that prevents the engine from reaching normal operating temperature, affecting ECT2 readings.

How to diagnose and fix it

Verify the code with a scan tool and check for any related codes in the PCM.
Inspect the ECT2 and AAT sensors and their connectors for physical damage, corrosion, or loose pins.
Measure the resistance of both sensors with a multimeter and compare to the manufacturer's temperature-resistance chart.
Check the wiring harness for continuity and shorts between the sensors and the PCM.
Perform a cold soak test by leaving the vehicle overnight and comparing ECT2 and AAT readings with a scan tool before starting the engine.
If the sensors and wiring are good, reflash or update the PCM software if a calibration bulletin applies.
Replace the faulty sensor or repair the wiring as needed, then clear the code and verify the repair with a test drive.

Cold Soak Correlation and Sensor Biases

A common oversight is replacing the ECT sensor when the actual fault is a biased ambient air temperature sensor that reads several degrees off, which skews the correlation.
The code can be set by a thermostat that is stuck open, causing the engine coolant temperature to rise too slowly and fall outside the expected correlation with ambient temperature.
In some vehicles, the ambient air temperature sensor is shared with the outside temperature display, so a faulty sensor may also cause incorrect readings on the dashboard.
Intermittent wiring faults that only appear in cold or wet conditions can set this code without leaving a permanent sensor failure, so a wiggle test of the harness is essential.
The PCM may use a model-based strategy that compares ECT2 and AAT after a specific soak time, and a weak battery or poor ground can cause voltage drops that mimic sensor faults.

Can I keep driving with P011F?

The vehicle is generally safe to drive with this code because it primarily affects fuel economy and cold-start behavior, but avoid extended idling or heavy loads until the fault is repaired. Have the system diagnosed soon to prevent potential drivability issues and to ensure accurate temperature readings for other engine management functions.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.