PCS malfunction light on b/c I forgot to plug in the MAF sensor?

You're kidding, right? What could the mass air flow sensor on your engine possibly have to do with the pre-collision system? Go back to your manual and see if you have any of those conditions that might actually cause it to fail.

 

Was there something else you were checking besides the air filter? The MAF sensor doesn't need to be disconnected in order to look at or replace the air filter. Maybe you forgot to reconnect something else?

 

Because the two systems are so totally unrelated.

Leaving the MAF disconnected will for sure trigger some lights, but it won't affect the pre-collision system. I'm also curious if you disconnected something else. As @CooCooCaChoo said, there's no need to unplug the MAF to change the air filter. In fact, there's no need to disconnect anything, so I can't guess what you might have unplugged. If nothing is unplugged, then there is something broken and coincidences really do happen sometimes.

 

Since the car is 'new to you'; what's the history? Has it been in a front end collision? You may have an intermittent after-market replacement part in there, tripping the sensors or a bad sensor. What is the current voltage reading at the battery and at the 'jump-point' under the hood?

 

That's pretty amazing that there could be any correlation between those sensors and PCS, but sometimes there's no explaining the reasoning of programmers. LOL! I've unplugged both those sensors probably a hundred times at work and never got a PSC fault on the few times I forgot to plug them back in.

 

Are those wire harnesses anywhere near each other? Could unplugging one jiggle the other loose?

 

The MAF sensor is at the back of the top of the tube feeding air to the air filter box. What I assume is the intake temperature sensor is down by the drivers side of the throttle body. As for the PSC sensor cable, I don't know, but it's not close to the air filter box. If I remember right, that's routed in front of the radiator to where the sensor is.

BTW, turning off the PSC system will also turn on the light. So it's not necessarily indicating a problem when it's lit.

 

This works. Everything may be rectified, but the car will continue to show trouble lights. It’ll take 4 or 5 start up, and the the lights shut off, not all at the same time.

I had this happen after leaving an oil catch can hose disconnected.

 

So, on modern cars EVERYTHING is interconnected. Most of the Advanced Driver Assistance Systems (lane departure warning, collision avoidance, etc, etc) require that braking systems (duhh!) and powertrain (torque management) have no faults.

Since these systems are doing "active" interventions to keep you alive, the engineers designed things to shut down if something can't be relied on to do what's expected .

Posted via the PriusChat mobile app.

 

Case in point: The tail lights on the new NSX will prevent the car from starting if they are blown out

Acura NSX Recalled to Fix Faulty Fuel Tanks and Brake Lights