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Juan Crespo
Juan Crespo, Tech Trainer
Category: Saab
Satisfied Customers: 1526
Experience:  A.S.E. Master Technician, Advanced Level, Emissions - Asian, Domestic, & European
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I just bought a 2004 saab93 from a friend. I hooked it up to

Customer Question

I just bought a 2004 saab93 from a friend. I hooked it up to a diagnostic tester and it threw 3 codes. P0300 random misfire, P0037 heater control circuit low bank 1 sensor 2, and P1312 this did not elaborate any further.. Where do I go from here? I know next to nothing about this vehicle!
Submitted: 1 year ago.
Category: Saab
Expert:  Juan Crespo replied 1 year ago.

Hi there.

Saabs sold in the US adhere to OBD-II protocols, which means that if you're familiar with those protocols, then you should be fine.

P0037 sets when Oxygen sensor heater circuit voltage is not detected by the onboard computer (PCM) - this is usually caused by a blown fuse #2, a bad O2 Heater relay, or shorted or open circuit/wires between the relay and the sensors.

P0300 sets when the PCM detects random misfires that cannot pinpoint to any specific cylinder - probably a result of P1312 in this particular case.

P1312 sets when the PCM detects more than one cylinder firing at the same time - this usually means bad coils.

I can guide you through a systematic diagnostic process to confirm all these faults. Just please be aware that you will have to use tools such as a Tech-II or equivalent scan tool and an automotive multimeter to execute some of the diagnostic procedures.