P1105 MAP/BARO SWITCH

[vmullane]

Hello all,

I have a 99 Q45t. Been trying to diagnose this CEL. Car seems to drive just fine, plenty of power but this CEL keeps coming on. Always comes up as p1105 map/baro sol and sometimes a p0330 knock sensor which I am attributing to the p1105 code messing with the fuel when it happens. I can clear it and it doesn't come on for about a week. My OBD2 reports the MAP @ 12.1 inHG when the malfunction happens. I am going to clear it and monitor it again. I was thinking probably just a vacuum line needs replaced or is clogged. The valve is under the Plenum though isn't it? I don't have emissions testing in my state so not too concerned with it just the CEL on drives me nuts.

Just trying to figure out if the repair will be worth it or if I should wait. I get great pricing on parts being an employee of NAPA so that makes it a little easier on my decision of fixing it or not.

[paranoidjack]

Sounds like you're right on.

There are two vacuum lines that go under the plenum and connect to the map/baro switch.

fgy33-plenum-removal-56k-beware-adding- ... 20801.html

I'm betting the switch is fine and it's a vacuum leak of some kind.

[vmullane]

Alright thanks for the reply. I loving the Q just wanna keep it that way.