The PCM has detected an abnormal input voltage reading from the intake air heater circuit.
Voltage variations that exceed the manufacturer’s stipulated level will result in a stored code and an illuminated service engine soon lamp. Some models require multiple drive cycles (usually 3) with a failure to illuminate the service engine soon lamp.
Symptoms accompanying this code are likely to be only the stored code and a service engine soon lamp.
Technicians report the most common cause of this code being a faulty intake air heater relay. Other causes may include shorted or open wiring or connectors, a burnt out heater element, a bad intake air heater blower, a faulty or disconnected intake air temperature sensor, or a faulty PCM. PCM failure is rare.
Intake air temperature sensors are frequently not reconnected after replacing the air filter or removing the air cleaner box for repairs. This may cause an intake air heater code to be stored.