So I had a corroded connector (that prevented my car from starting) repaired at a shop and I'm pretty sure an SRS light came on after that (it could have gone off earlier I suppose during the car not starting issue and I just didn't notice it, but it definitely wasn't on earlier) and I took it back to them and they read and cleared the codes. It hasn't come back on, but I'm still wondering what the codes might mean and if there is an underlying problem. The codes are:

27 P-PT SQ TRBL2
56 D-PT DRI CIRL
66 D-PT SQ B1
1B FL IMP 5N5R2

Does anyone know what these could be or where to find out? My internet searching hasn't helped very much.

 

27 is drivers seat belt retractor, specifically an open circuit
56 is drivers seat belt retractor, specifically the voltage driver in the ecu
66 is drivers seat belt retractor, specifically the power supply to the driver in the ecu
1B is drivers impact sensor (over radiator), specifically an open circuit

I'd clear them out and see what returns after the repairs have now been made. If they come back, you will want to check your wiring at the radiator area for the impact sensor carefully. Also check the wiring in the drivers kick panel and bottom of the B pillar for corrosion/damage.
If all look well, I would send the ecu out for inspection/repair first since you have internal faults as well. The 66 will only occur if there is wiring shorted to 12V somewhere or there is internal issues in the ecu. So if you are sure the wiring is OK, the ecu needs to be sent out for check.
The impact sensor and the retractor are certainly possible to be bad, but given that you have recently had corrosion issues and you have several indications of ecu related issues, I would hesitate on replacing them as you may find that the ecu resolves those issues as well. If it is suspect, all functions of it are suspect as well. It will be much cheaper to send the ecu out for inspection (or install a used one) than it will be to replace the retractor and the impact sensor and find out that you may not have needed them.