W140 SRS light on after battery drain

[1998S280]

Morning all,
I only use my W140 once a month for a 300 mile round trip to my work office and when I moved at the weekend to give it a wash before this months journey the battery was completely flat. I tried a power pack and also tried jumping from a spare battery but neither worked so I put the battery on charge.
The battery was new in 2023 so I dont expect it to be the battery but did notice that when recharging it never reached "full". After 3 or 4 hours I gave it a go and it started OK but with the SRS light on.
I went to move the car yesterday to go for fuel as I intended to use the car tomorrow for the work journey but the battery was flat again, luckily I have a spare identical battery so I swapped them over and it started up but again the SRS light is and and doesnt go away even after 5 minutes of running.
I suspect a parasitic drain on the battery from somewhere causing the flat battery, any thoughts on this and the SRS light please?

thank you

 

[1998S280]

no thoughts on the SRS light coming on and remaining on after a flat / disconnected battery?
can codes be removed with the cheap OBD diagnostics boxes and phone app?

 

[RichardF]

For SRS codes you'll need STAR or professional equivalent. My local indy does it in exchange for a few beer tokens.

 

[1998S280]

thanks Richard

 

[1998S280]

should the OBD port be behind the flap in the drivers side footwell?

 

[grober]

FAULTY ALTERNATOR?

 

[Wearsthefoxhat]

Wouldn’t this use the 38 pin HHT diagnosics port in the engine bay as might be too early for obd 16 pin ?? but I am no expert.

 

[DSM10000]

FAULTY ALTERNATOR?

Faulty keyboard?

 

[1998S280]

where is the 38pin port located please?

 

[grober]

where is the 38pin port located please?

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