33: Right Front Sub Sensor Failure

Hardware fault

What 33 means

Sub sensors are satellite crash sensors mounted ahead of the passenger compartment, where they feel an impact before the main control unit does. The right front unit covers the passenger side of the front end. When it fails, the control unit loses its early read on that corner and stores code 33 against the sensor.

The mounting location is what drives most failures. A sensor at the front of the car lives with road spray, salt, heat from the engine bay, and the occasional parking lot tap. Its connector sits in the same environment, which is why corrosion shows up as often as an electrically dead sensor.

Common causes

• A failed sensing element inside the right front sub sensor
• Corrosion in the sensor connector from road salt and standing water
• Impact damage to the sensor or its bracket from a front end collision
• A loose mounting bolt allowing the sensor to move in its bracket
• A used sensor installed in a previous repair that had already taken a hit
• Harness damage at the front of the car from rodent activity or road debris

Crash data or hardware fault?

Code 33 reports a component in its present condition rather than a crash record. The control unit checks the sub sensor at every key cycle and the code comes back until the part is right. Crash data is the other type of entry: locked in when airbags fire, untouchable at the vehicle, and cleared only by a module reset.

Does our reset clear it?

Mailing the control unit in will not repair a sub sensor. Our reset service removes stored deployment data, so it belongs in this job only if the car was in a frontal crash and the module carries that record too. Replace the failed sub sensor with a genuine OEM part, then confirm the light goes out before deciding anything about the module.

Which makes throw it

Subaru assigns code 33 to a right front sub sensor failure. Sub sensor is Subaru's own name for these satellite crash sensors, so parts listings and repair information may also call them front impact sensors.

What to do next

Get the sensor connector into good light and check it for corrosion before ordering the part, since a green connector at the front of a Subaru is common in salted climates. Make sure the sensor is tight in its bracket and the bracket is not bent. Inspect the harness for rodent damage while you are in there. If the sensor is genuinely dead, we sell genuine OEM Subaru front sensors matched by VIN at 501-988-0611. Related codes: 2C, 41, B1B71.