I've recently had OBD codes P0130 and P1237. The cause was just a bad vacuum line, and I'd like to pass the info on.

The check engine light came on, stayed on for about 3 drive cycles, then went off. A few days later the same thing happened, and then a few days after that it happened again. An OBD reader showed code P0130 O2 Sensor Circuit Malfunction (Bank 1 Sensor 1). After about 4 of these cycles, the engine began to run poorly: sometimes idle would dip to too low an RPM, and sometimes the engine would bog down when pressing the gas pedal. At this point the OBD reader showed 2 codes: P0130 and P1237 Secondary Upstream Manifold Air Pressure Sensor Low.

Several posts in this forum suggested the problem could be a bad O2 sensor or bad wiring to it, and one or two suggested a vacuum leak. One post had a link to www.obd-codes.com/p0130, which suggested several possible causes to the P0130.

Checking it out under the hood, I found a vacuum hose disconnected from a nipple on the intake manifold. I re-connected it, erased the two OBD codes, and ran the car. It ran normal again, and after several drive cycles the two codes have not returned. So, it seems that the disconnected hose caused the two OBD codes and the rough running.

I don't know how the hose became disconnected. It wasn't cracked or hard, and its in an area that seems like nothing would pull on it. Facing the car from the front, the hose is on the top of the engine, at the left side intercooler bell. There's a tee in it, and I think it connects to the bypass valve, and maybe the fuel pressure regulator. I imagine the intake manifold experiences both vacuum and positive pressure, but the positive pressure shouldn't be enough to blow off the hose. So ???

Anyway, its working fine now, and cost only research time to fix it...thanks to posters here.

 

Sounds like a good result, and yes that network of vacuum lines does connect to the by-pass valve, P1237 is a BPV code. Glad the fix as pretty cheap! It's amazing how many little details can bring such a complex piece of machinery to a crippling halt so quickly. I know a fw people that have zip-tied the vacuum lines in place to prevent recurrence of such slippage.

 

Had same issue on my Mini p1237 save me going to dealer found vacuum line of that goes to intercoolernon left sisde of car