Hi,
Interesting set of codes. If I had to guess, I'd say your service messed up some of the electrical connections because the codes do not point to anything related and they all indicate a short of some component. The codes are:
- P1124 - Fuel Pump Relay Output Stage - Short, No signal, Below Lean Mixture threshold, Above Rich Mixture Threshold
P1126 - OČ Sensor, Cyl. 1-3 - Implausible Signal, Short to Ground, Short to B+
P0150 - Pre-Catalyst OČ Sensor, Cyl. 1-3, Short to Ground, Short to B+, Implausible Signal
P1319 - Misfire, Emission Relevant
Now, 3 of these indicate a short. Either something wasn't reconnected or something was accidentally disconnected. You can try disconnecting the Battery for 5 min., reconnect it and see if the Codes return. If they do, I'd get it back to the Dealer and have them check it with the PST2. Hope this helps...
Happy Motoring!... Jim'99