Faulty bank 2 intake air temperature sensor with an internal short; Signal wire shorted to ground or chafed against bodywork or the engine; Water, corrosion or damaged pins in the sensor connector; Signal wire shorted to the sensor ground wire inside the loom; Damaged or heat-affected wiring near the intake or turbocharger pipework; Fault inside the engine control unit's sensor input circuit.

P00AC

Intake Air Temperature Sensor 1 Circuit Low Bank 2.

Generic
Powertrain
Generic code
Low severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
0: AreaFuel and air metering, auxiliary emission controls
AC: FaultThe specific fault in that area

What it means

P00AC means the engine control unit has seen the signal from intake air temperature sensor 1 on bank 2 fall below the expected range. A low signal voltage usually means a short to ground or a sensor fault, because the unit reads it as an implausibly high air temperature. The sensor's position and the way bank 2 is defined depend on the engine, so check the layout for the specific model.

Symptoms

Engine warning light on
Poor cold starting or rough running when cold
Reduced power or hesitation under load
Slightly higher fuel consumption
Rough idle
Other intake or boost related codes stored alongside it

Possible causes

Faulty bank 2 intake air temperature sensor with an internal shortlikely
Signal wire shorted to ground or chafed against bodywork or the enginelikely
Water, corrosion or damaged pins in the sensor connectorpossible
Signal wire shorted to the sensor ground wire inside the loompossible
Damaged or heat-affected wiring near the intake or turbocharger pipeworkpossible
Fault inside the engine control unit's sensor input circuitrare

How to diagnose

Read all stored codes and freeze frame data, noting engine temperature, intake air temperature reading and whether the fault is current or intermittent.
Compare the live bank 2 intake air temperature value with the bank 1 sensor (if fitted) and the coolant temperature on a cold engine; they should be close.
Check the live reading while wiggling the connector and wiring to see whether it jumps or drops out.
Inspect the sensor, connector and loom for damage, water ingress, corrosion, chafing and heat damage.
Unplug the sensor with the ignition on: the reading should move towards a very cold value. If the fault stays, suspect the wiring or control unit.
Measure the sensor resistance and compare it with the manufacturer's temperature table for the specific engine.
Check the signal and ground wires for continuity and for shorts to ground, following the wiring diagram for that model.
Check the 5 volt reference and ground at the connector, and only then consider the control unit.

How to fix

Replace the bank 2 intake air temperature sensor if its resistance is out of specification.
Repair or replace shorted, chafed or damaged wiring and secure it clear of sharp edges and heat sources.
Clean or replace corroded or damaged connectors and terminals, and refit seals correctly.
Repair the loom fault causing a short between signal and ground.
Repair or replace the control unit only after the wiring and sensor are confirmed good, following the manufacturer's procedure.

Can I keep driving?

Low severity

The car can normally be driven, as the control unit will use a default air temperature value. Book it in soon, because poor running or higher fuel use may continue and a wiring fault could get worse.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.