Faulty intake air temperature sensor on bank 2; Short to ground in the sensor signal circuit; Corroded, damaged, or disconnected electrical connector at the sensor; Damaged wiring harness between the sensor and the engine control module; Failed engine control module (less common); Intake air temperature sensor circuit shared with the mass airflow sensor (if combined) with an internal fault

DTC codes / P00xx · Fuel and air metering and auxiliary emission controls / P00AC

P00ACIntake Air Temperature Sensor 1 Circuit Low Bank 2

Q: What does code P00AC mean?

Intake Air Temperature Sensor 1 Circuit Low Bank 2. P00AC means the engine control module has detected an abnormally low voltage signal from the intake air temperature sensor on bank 2, which is the sensor that measures the temperature of the air entering that bank of the engine. The computer expects the sensor's signal voltage to stay within a calibrated range, and a low voltage typically indicates a short to ground, a faulty sensor, or a wiring problem.

P00AC means the engine control module has detected an abnormally low voltage signal from the intake air temperature sensor on bank 2, which is the sensor that measures the temperature of the air entering that bank of the engine. The computer expects the sensor's signal voltage to stay within a calibrated range, and a low voltage typically indicates a short to ground, a faulty sensor, or a wiring problem.

SystemPowertrain

Code typeGeneric (all makes)

SeverityLow

Fix difficultyIntermediate

AreaFuel and air metering and auxiliary emission controls

Symptoms you may notice

Illuminated check engine light, often with no other noticeable symptoms
Rough idle or poor engine performance when the engine is cold
Decreased fuel economy or black smoke from the exhaust if the engine runs rich
Hard starting or stalling shortly after startup in cold weather
In rare cases, a slight hesitation or surge during acceleration

Common causes, most likely first

Faulty intake air temperature sensor on bank 2
Short to ground in the sensor signal circuit
Corroded, damaged, or disconnected electrical connector at the sensor
Damaged wiring harness between the sensor and the engine control module
Failed engine control module (less common)
Intake air temperature sensor circuit shared with the mass airflow sensor (if combined) with an internal fault

How to diagnose and fix it

Scan all modules and record freeze-frame data to confirm the code and check for related codes
Visually inspect the bank 2 intake air temperature sensor and its connector for damage, corrosion, or loose pins
Measure the sensor's resistance with a multimeter and compare it to the manufacturer's temperature-resistance chart
Check the signal circuit for a short to ground using a multimeter or test light with the sensor disconnected
Repair or replace any damaged wiring or connector terminals as needed
Replace the intake air temperature sensor if it fails the resistance test or if the circuit tests good
Clear the codes and perform a road test to verify the repair and ensure the code does not return

Don't overlook the shared sensor circuit

Many vehicles combine the intake air temperature sensor with the mass airflow sensor in a single housing, so a low signal on bank 2 may actually be caused by a failing mass airflow sensor rather than a separate IAT sensor.
A short to ground in the signal wire can be intermittent and only set the code when the engine harness flexes, so wiggle-testing the harness while watching live data is a crucial step.
The code can set if the sensor is unplugged or if the connector is not fully seated after recent service, so always check for recent repairs before condemning parts.
On some engines, bank 2 intake air temperature is inferred from other sensors, and a faulty ambient temperature sensor or wiring can skew the calculated value and set this code.
Replacing the sensor without checking the reference voltage and ground at the connector can lead to a repeat failure if the underlying wiring fault remains.

Can I keep driving with P00AC?

The vehicle is generally safe to drive with this code because the engine control module substitutes a default intake air temperature value, but fuel economy and cold-start performance may suffer. Avoid extended driving if you notice rough running or black smoke, and have the fault diagnosed soon to prevent potential catalytic converter damage from a rich condition.

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.