I've just recently discovered this misfortune to my 911, and to the wife's Transit Connect.
We believe it's a squirrel (or worse, a pair of them). The Transit Connect got it's #2 fuel injector wires chewed right through, and that was simple enough to fix. I learnt that a soldering iron that runs on 4 AA batteries actually is worth having, and the biggest frustration was my own old person eyesight. It seems that 55 years of being short sighted makes one used to having good close in vision, and cataract surgery taking that away isn't always as great as it seems. Why can we have auto-focus cameras, but not auto-focus glasses.
Anyway, the first thing I noticed on the 911 (2002 Carrera, manual transmission) was after it moved a few feet, the ABS and PSM announced itself as being disabled. After a few more feet, there was a check engine light, which turned out to be a MAF fault.
Closer inspection revealed that the squirrel had climbed up between the catalytic converters, and gone to the right rear side of the engine compartment, and chewed on 4 wire bundles.
The 4 wires in the MAF sensor bundle were all severed
both O2 sensor wire bundles were chewed on, but apparently non severed (by inspecting after taking off the car). I haven't yet tested the heater continuity on these, but I will.
The 4th wire bundle contained 3 wires, and all were severed. I don't know the function of this 4th bundle, I'm hoping somebody here might.
The O2 sensors each have plug and socket disconnects, and these physically mount to plastic clips that are part of a plate attached to the body of the car. this plate also retains a 5 wire connector
containing 3 pins with wires attached (and these 3 wires are severed) However, it looks like in the case of this connector, the plug is merely retained by the plastic plate, but there is no electrical connection to anything, at least on my car. Does anyone know what this connector would be for?
I imagine that when I repair the MAF wires, I'll be able to clear that code, but I still need to find the cause of the ABS/PSM failures.
The speed sensor wires have all been checked, and have NOT been chewed on. An Autel scanner that I have can display wheel speed on all 4 wheels, so that seems good.
As far as I know, all the other sensors for ABS and PSM are inside the car, and there are no signs that the squirrels have been inside.
I have not yet checked fuses, but but I intend doing that.
I believe that if ABS goes out, then PSM will always disable, but I don't know if the reverse is true.
Does anyone know if a MAF fault would also disable ABS? It doesn't seem unreasonable, but I don't know if it's actually the case. When I drove the car slowly, the short distance to my lift, it behaved fine despite having no MAF sensor, but that's not much of a surprise; reversion to an Alpha-N mode can work quite well. But I would think that Traction Control mode would want the airflow system to be fully operational. Clearly this IS wishful thinking, but I don't know if that's all it is.
I see, further forward on the right side of the engine compartment what appear to be 2 large round wire bundle connectors, which don't look or feel chewed, but they are going to be much harder to inspect. I hope I don't have to.
Thanks,
Michael