B0789 Seat Auto Trouble Code on vehicles with electronically controlled automatic transmissions, the 3-4 shift solenoid is responsible for actuating the hydraulic circuits to activate clutches or bands that change gears inside the automatic transmission.
The crank but won't start condition, along with the trouble codes may make you think you've got a PATS anti-theft system problem. However, Ford reports that these codes are all related to software bugs. The only way around the problem is to reprogram the PCM with the latest software.
Excessive air inflow can be caused by a vacuum leak, a dirty sensor or, an exhaust gas recirculation valve not closing properly. If the problem is not enough fuel, the culprit may be dirty injectors or fuel filters, a weak fuel pump or a leaky fuel pressure regulator. The lean fuel mix error may be accompanied by rough idling, engine misfires, hesitation during acceleration and overall poor engine performance.
B0789 meaning and repair processes are the same for all Seat models.
B0789 Seat Trouble Repair Process:
The sensors receive a 5 volt reference signal from the PCM. As pressure readings change, the sensor varies the voltage and the computer reads that to determine input. In the case of a broken wire, the sensor never sees the voltage and the computer assumes a major fault. So if you get this B0789 Seat code, first check to make sure you're getting a good 5 volt reference signal at the sensor.
It works by having a slightly higher than normal opening temperature, which still works the same way as regular ones, but it also has a heating coil, which means the ECU can open the thermostat earlier and keep the engine slightly cooler.