Q: po598 code on bmw 335i 2007 cause

If the battery voltage is way out of range (low), yes it is possible. The complex electronic systems on modern vehicles work within narrow voltage ranges and so a faulty battery can cause malfunctions in devices that are electrically powered. If the battery is faulty, of course, it should be replaced anyway and once that is done you will surely have a definitive answer to whether the battery is, or was, a cause of the code. To obtain a load test of the battery, and replacement of the battery if warranted, please use Your Mechanic’s battery diagnostic and service page and the responding certified mechanic will get this taken care of for you. If the code (P0598) persists, even with a confirmed good battery, the usual causes of that code are a loose or corroded connector on the thermostat, a coolant leak, the thermostat itself has failed, there is a short or open in the wiring harness between the computer and the thermostat, or there is a fault in the control computer itself (rare). If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.