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  1. Code P0128 *replaced Thermostat* Code P0128 AGAIN!

    General E46 Forum
    Hey guys, I'm having a bit of a strange issue with my 2001 325xi. I first started getting this P0128 code that suggests that my thermostat might be stuck open. I looked it up on the forums and then found that i should probably replace the Thermostat, so I got myself an eBay thermostat (no...
  2. Non-M thermostats, poll

    General E46 Forum
    How many thermostats have failed in your car or cars? M52TU and M54 thermostats are a well known weak spot in BMW cooling systems. They usually fail open causing the car to run cold, usually throwing a check engine light. An OBDII code reader will show a P0128 (Coolant below regulating...
  3. Check Engine Light

    General E46 Forum
    My check engine light came on a few days ago and came back with a P0128 code (something about the coolant temperature being too low). It did this once about 6 weeks ago, but the guy told me not to worry about it if the light didn't come back on soon. Should I be concerned about it? If so, how...