45-2X: Second Left Side Sensor Failure

Hardware fault

What 45-2X means

Side impact protection can depend on more than one sensor per side, placed at different points in the body so the module can tell a real impact from a door slam or a pothole. The second left side sensor runs a self test like the others and reports what it finds. A failure report puts 45-2X in memory and takes the system offline.

Since the sensor is still communicating, the wiring and the connector are working. The fault is inside the device. Sensors mounted in the lower body or rear structure see moisture from drains and seals, along with the vibration and temperature swings that come with a long service life, and eventually the electronics inside stop passing their own test.

Common causes

• Moisture past the housing seal corroding the sensor internals
• Long-term vibration and heat cycling wearing out the internal electronics
• A sensor carried over from a previous collision repair instead of being replaced
• Shock transmitted through the bracket during body or trim work
• A loose or angled mount putting the sensor out of its intended orientation

Crash data or hardware fault?

45-2X reports the sensor's own condition at the time of the test, so it is a live hardware fault rather than a locked crash record. Install a working sensor and the report changes. Crash data cannot be handled that way, since the control module writes it during a deployment and holds it until the module itself is reset.

Does our reset clear it?

No reset changes what has failed inside the sensor, and the code comes back on the next self test. Replacement is the repair. Our mail-in reset applies to a control module that has deployment data stored in it, and on a car that took a side impact both things may need attention in the right order.

Which makes throw it

This code sits in our Acura index. Confirm which sensor position the code names on the vehicle in front of you before ordering, since the left side can carry more than one and they are not interchangeable by position.

What to do next

Verify the location first, because buying the wrong side or the wrong position is the most expensive mistake on this code. Inspect the sensor body and connector for corrosion and cracks, then check the mount is flat and tight. With the mounting confirmed and the failure report still present, fit a genuine OEM Acura side impact sensor for that position. Related codes: 44-1X, 46-1X, U1100.