I am having the same problem with my 2002 525I. Its in the shop as we speak and the two codes are 500-speed sensor and the 128-Thermostat coolant temp. I was informed that the ABS Module has to be replaced and could range from 1,000. to 3,000. new or refurbished. i dont know what to do.

128-coolant thermostat,137 bank 1 sensor 2 after catalytic conv.exhaust gas temp.sensor 545 bank 1 sensor 1.

code p 128 refers to coolant thermostat---coolant temp below thermostat regulating temperature ====causes --mechanical fault
you say that you have replaced the thermostat and it is just under 210 F which is 99 c or almost boiling point
you will have to investigate why it is running so hot.
check that you put the thermostat in correctly ( bulb section to block/head water
Next point --the codes are originated by the coolant temperature sensor ( puts the fans on and sets the ECM fuel/air ratio for the engine ) so to get it off you will need to reset with a scan tool

P0038 - HO2S Heater Control Circuit High Bank 1 Sensor 2
P0128 - Coolant Thermostat (Coolant Temp Below Thermostat Regulating Temperature)
P0336 - Crankshaft Position Sensor Circuit A Range/Performance
P0386 - CKP Sensor B Circuit Performance.
your most likely need to replace the crankshaft sensor and probably will take care of the 0336 and 0338 codes.
you then need to check your coolant level, if low fill and look for leaks, if not low, most likely replacing the thermostat will correct other two codes

We are assuming that you are talking about P0128 code.

P0128 OBD-II - Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)

This means that the engine's PCM detected that the engine has not reached the required temperature level within a specified amount of time after starting the engine. The intent of the P0128 code is to indicate a faulty thermostat. Similar codes: P0125

In determining the engine did not reach a "normal" temperature, it takes into account the length of time the vehicle has been running, the intake air temperature (IAT) sensor reading, the engine coolant temperature (ECT) sensor reading, and the speed of the vehicle.

Contact us if need additional details.

P0128 is a temperature error code indicating: ECT Sensor Below Thermostat Regulating Temperature

Possible causes are:

1. Check the operation of the thermostat (it may be stuck open)
   
2. Coolant level is too low, or the coolant mixture is incorrect
   
3. ECT sensor signal circuit has a high resistance condition
   
4. ECT sensor is damaged or it has failed
   

In most cases, assuming the coolant level is full, changing the thermostat will correct your problem.
Thank you for using Fixya!

p0116 is-- engine coolant tempurature ckt/range performance----- p0 128 is--coolant temp below thermostat regulating temperature. to fix these 2 codes are similar, change coolant tempurature sensor and thermotat all should be ok. make sure coolant in radiater is full. hope this helps you.

A code P0128 may mean that one or more of the following has happened:

• Low engine coolant level
• Leaking or stuck open thermostat
• Faulty cooling fan (running too much)
• Faulty coolant temperature (ECT) sensor
• Faulty intake air temperature (IAT) sensor

PO-128 Coolant Thermostat, Temp Below Regulating Temperature

Leaking or stuck open thermostat
Coolant temp sensor
Cylinder head temp sensor
Engine coolant level

You could have more than one issue

The only way to answer your questions,is to put a scanner on your vehicle,and see what codes you have.
The codes you get,do not indicate a failure,necessarily
You have to follow a diagnostic process,to find any problems.
If you have been going to auto parts stores,to have codes read,and have no knowledge or intension of doing your own work,you need to find a good repair shop, and just have it repaired,fairly soon

YOU FAULTY COOLANT SENSOR OR PCM.

P0128: 'Coolant Thermostat (Coolant Temperature below Thermostat Regulation Temperature)'
P0334: 'Crankshaft Position Sensor Circuit, Electrical fault'
P0002: ??
P0100: 'Mass Air Flow Circuit, Range/Performance'

The Mass air flow sensor creates all the other problems. This is a very common problem with S60 this old.

It is very likely your thermostat is stuck open. Replace the thermostat and it should be fine.

P0128 Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)