Outputs of this test mode are displayed as 2-digit ATM codes which identify malfunctions to a specĪCTUATOR – A device that moves or controls another device in response to a mechanical, hydraulic, pneumatic, or electrical input.Ī-D (ANALOG-DIGITAL) CONVERTER – An electronic circuit which converts an analog input to a digital output.ĪFTER TOP DEAD CENTER – Refers to crankshaft position relative to the ignition timing in degrees.ĪICV (AIR INJECTION CHECK VALVE) – One-way check valve which prevents hot exhaust gases from backing up in the hose and air pump in the event of air pump belt failure, abnormally high exhaust system pressure, or if the air hose ruptures.ĪIR – Secondary air injection (formerly thermactor).ĪIR CHARGE TEMPERATURE SENSOR – A thermistor (temperature-controlled variable resistor) located in the intake manifold.ĪIR CLEANER VACUUM DIAPHRAGM – A diaphragm, controlled by the air temperature sensor, which controls the position of the door in the air cleaner duct to allow warm or cold air into the carburetor.Īir Conditioning Clutch – Sends signal input to computer relating status of air conditioning clutch.ĪIR GAP – The space between the spark plug electrodes, motor and generator armatures, field shoes, etc.ĪIR RELIEF VALVE (ARV) – Device which vents excess air pump output into the engine compartment when a specified discharge pressure is reached.ĪIR SWITCHING/RELIEF VALVE (ASRV) – The ASRV directs air injection to the exhaust port or downstream injection port, depending on engine operating temperature, and regulates system pressure by controlling air pump output at high engine speeds (when pressure reaches a predetermined level, soĪIR/FUEL (AF) MIXTURE – A ratio of the amount of air that is mixed with fuel before it is burned in the combustion chamber.ĪIS (AUTOMATIC IDLE SPEED) MOTOR – Increases or decreases the size of an idle air bypass to raise or lower idle speed. (This signal was not used on 1984-85 EFI models).Ī/CL DV – Air Cleaner Duct and Valve Vacuum MotorĪ4LD – Ford automatic 4 speed lock-up converter drive.Ī4R70W – Automatic Overdrive Electronic Wide Ration TransmissionĪCR4 – Air Conditioning Refrigerant, Recovery, Recycling, RechargingĪCT – Air Charge Temperature sensor or signal circuit.ĪCTUATION TEST MODE (ATM) – The diagnostic mode used by the vehicle’s on-board computer to activate and deactivate specific output circuits to determine if they are operating properly. The computer increases engine speed to compensate for the additional load.
The computer activates the AIS motor to give a one-time increase in engine speed when the A/C clutch engages.Ī/C CUT-OUT RELAY – Device which operates under control of the vehicle’s on-board computer to prevent compressor clutch engagement under wide open throttle conditions.Ī/C SWITCH – Device which sends a signal to the vehicle’s on-board computer to indicate the air conditioner is operating.
4EAT – Ford electronic automatic 4 speed transaxle.Ī/C CLUTCH SWITCH – Device which sends a signal to the vehicle’s on-board computer to prevent engine idle speed from varying when the compressor clutch cycles.