54-4X: SRS Unit Internal Fault

Hardware fault

What 54-4X means

Control modules run a series of internal checks rather than one single test, and different failures inside the unit produce different codes. 54-4X sits in the same family as 53-2X and carries the same practical meaning: the SRS unit is reporting an internal fault, so it will not arm the system or make a deployment decision until the fault is gone.

Because the fault is inside the module, the usual wiring diagnosis does not apply. What does matter is everything feeding the module. A weak battery, a corroded ground, or a poor connection at the module can produce behavior the module reads as an internal problem, which is why supply and grounds get checked before the unit is condemned.

Common causes

• Water reaching the module housing from a cowl, windshield, or floor leak
• A weak battery or a bad module ground producing unstable supply voltage
• Electrical damage from a jump start done backward or from welding on the vehicle
• Internal component or solder joint failure after a long service life
• Corrosion at the module connector working into the board

Crash data or hardware fault?

This is the module describing its own hardware, not a crash record. Crash data is the separate, permanent entry written when airbags actually deploy. A module can carry an internal fault and a deployment record at the same time, and knowing which one you are dealing with decides whether the unit can be put back in service.

Does our reset clear it?

A mail-in reset clears stored data and stored faults from the module, and it is worth doing on a unit showing 54-4X when the condition is stored rather than an active hardware failure. If the internal fault is real and live, the reset will not resolve it and the module needs to be replaced. We run the process and report what the module does.

Which makes throw it

54-4X is carried in the Acura section of our code list, in the same block as 53-2X. Verify you are reading the Acura index for the car in front of you before treating the module as the problem.

What to do next

Measure battery voltage and check the module grounds before pulling anything apart, because a supply problem can imitate an internal fault convincingly. Inspect the module connector and its mounting area for moisture. When the electrical supply is confirmed good and the code stays, remove the SRS unit and send it to us at 501-988-0611, and we will run the reset and tell you whether the module can be reused. Related codes: 53-2X, B0016, B1044.