What does Ford fault code P0073:00 mean and how to fix it UK?

Ford fault code P0073:00 indicates a high circuit voltage in the ambient air temperature sensor, which measures outside air temperature to help your Ford's ECU optimise engine performance. This common issue affects Ford models like the Focus, Fiesta and Kuga, and requires proper diagnosis and code clearing procedures to avoid potential electrical system problems. The ambient air temperature sensor works alongside other temperature sensors in your Ford - including the coolant temperature sensor (typically located near the thermostat housing) and intake air temperature sensor (often found in the air intake system). When dealing with P0073 in UK Ford vehicles, never attempt to clear the code by disconnecting the battery, as this can reset your ECU's adaptive memory and potentially lock systems like your Ford Sync audio unit. Instead, use an OBD-II scanner specifically compatible with Ford systems after addressing the underlying issue, which could range from a faulty sensor (common in older Ford models exposed to British weather) to wiring damage or connector problems. For accurate diagnosis on modern Fords like the Puma or Transit Custom, a professional diagnostic tool such as Ford's own IDS system may be necessary to properly interrogate the vehicle's systems.

Ford fault code P0073:00 indicates an issue with the ambient air temperature sensor circuit, specifically a high input voltage. This sensor, usually located near the front grille or windscreen, helps the engine control unit (ECU) adjust performance based on outside temperatures. A fault can affect fuel efficiency and climate control accuracy.

To diagnose and fix:

1. Check the sensor wiring for damage or corrosion. Look for frayed wires or loose connections near the sensor.
2. Test the sensor’s resistance with a multimeter. Compare readings to Ford’s specified values (typically 2-3k ohms at 20°C).
3. Inspect the sensor for physical damage. If cracked or corroded, replacement is needed (costs around £20-£50 for parts).
4. Clear the fault code with an OBD-II scanner after repairs. If the code returns, consult a mechanic to check the ECU or wiring loom.

Common models affected include the Ford Focus and Fiesta. Ignoring the issue may lead to incorrect climate control operation but won’t typically cause engine damage.