Necessity of the mod = SVS fix(wiring mod option B) "graphic" explanation

The SVS issue was explained many ways but never this way, i edited the internal diagram of the ABS modulator concentrating on the SVS module(SWO500040), i marked where IMO the problems usually are with orange but in case of oil ingress to the switches those resistances(with red) will be affected, also contacts within the modulator are getting weak and the fault is the same, with purple are the external wires of mod option B, blue is the switch pack(SWO500030), there are two important notes on the original scheme:
* TOTAL RESISTANCE INCLUDING CONTACT AND CRIMP RESISTANCE: R<0.017 OHMS for the connection which gives the main earth(that big earth connector below the multiplug
**TOTAL RESISTANCE INCLUDING CONTACT AND CRIMP RESISTANCE: R<0.04 OHMS on the refference earth(ground) circuit from SLABS to pin 8 of multiplug

so there will be SVS related fault code if the resistances of the switch pack are out of range(which from MY experience is rare) and if one or both of those two earth circuit resistances are out of that "tight" range or there's an internal bad contact on that circuit, so taking with external wires(purple in the scheme) the switch pack directly between earth and the SLABS ECU's SVS input the internal circuit of the modulator is bypassed and the only case in which the 3 amigos will come on again is if the switches will be ruined by fluid ingress ... that's why i'm saying that the brake fluid ingress is not the most common issue cos many of those who made option B didnt replace the valve seals, some of them nor the switch pack just made the wiring mod and they haven't seen the 3 amigos generated by SVS fault code again...i hope it makes sense

sierrafery said:

The SVS issue was explained many ways but never this way, i edited the internal diagram of the ABS modulator concentrating on the SVS module(SWO500040), i marked where IMO the problems usually are with orange but in case of oil ingress to the switches those resistances(with red) will be affected, also contacts within the modulator are getting weak and the fault is the same, with purple are the external wires of mod option B, blue is the switch pack(SWO500030), there are two important notes on the original scheme:
* TOTAL RESISTANCE INCLUDING CONTACT AND CRIMP RESISTANCE: R<0.017 OHMS for the connection which gives the main earth(that big earth connector below the multiplug
**TOTAL RESISTANCE INCLUDING CONTACT AND CRIMP RESISTANCE: R<0.04 OHMS on the refference earth(ground) circuit from SLABS to pin 8 of multiplug
View attachment 129656
so there will be SVS related fault code if the resistances of the switch pack are out of range(which from MY experience is rare) and if one or both of those two earth circuit resistances are out of that "tight" range(thats the most common IMO), so taking with external wires the switch pack in series between earth and the SLABS ECU's SVS input the internal circuit of the modulator is bypassed and the only case in which the 3 amigos will come on again is if the switches will be ruined by fluid ingress ... that's why i'm saying that the brake fluid ingress is not the most common issue cos many of those who made option B didnt replace the valve seals, some of them nor the switch pack just made the wiring mod and they haven't seen the 3 amigos generated by SVS fault code again...i hope it makes sense

Click to expand...

Thanks again. That makes sense and it also probably explains why (rarely) people still get the svs fault after doing the electrical mod if they had fluid leak and didn’t fix that too. Cheers guys.

It can be due to those earth resistances too where the **'s are

Cheers Ferry!