I have an 07 Accord 4cyl SULEV 5 spd. Lately I've been getting an airbag warning lamp come on after starting when cold, below 20F. The light will stay on until re-starting and it needs to be driven 2-3 miles before the light will stay off. I borrowed a Solus scan tool and found a stored 53-33 code, which translates to internal failure of SRS unit. Of course it wasn't cold enough while I had the tool to replicate the problem. So my question is is there anything external to the SRS unit that can cause a 53-33 code and, if so, what should I test before replacing the SRS unit?

 

An internal failure of the SRS unit would require replacement of the unit. External wiring will have little to do with this code unless the power and ground circuits were interrupted.

The SRS unit charges capacitors to ensure the airbag can deploy even with a battery disconnect for a specified amount of time.

A frozen capacitor may prevent that capacitor from fully charging until the circuit warms up, which could explain the code.

I do not have access to that particular code right now, or any service bulletins that may apply. Those need to be checked as well.

 

Clean your battery terminals and check the cables for corrosion in the wire itself. I have seen dirty terminals, corroded power/ground wires, bad batteries, and anything causing low voltage situation including excessive draw from starter cause this fault several times. Put a voltmeter at SRS unit constant power and observe voltage when cranking. Cold weather will affect this issue. If all checks out replace SRS module. When first powering up new SRS unit have zero weight on pass. Seat and have pass seat in full rear and upright position to ensure OPDS and SWS initialization

 

I'm not thinking it's voltage, though I didn't measure it at the unit yet. I went out to check voltage and found the light was on. I had the scan tool, so I hooked it up. After trying to get some useful info out for a short bit, the light went out. I never started the engine. It seems it is heating, but electrical heating of the unit and not engine heating. Huh.