service engine soon (p0128) on 2004 BMW X5

service engine soon came up and i use my scantool to read and get p0128 and clear it and it cameup again a week after. Please what do i do?

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5 answers 2 comments
I would make sure your thermostat is working correctly before jumping to any conclusions. it is the most common failure for the 128 code.

Roy
mastertch6371 your correct i forgot to add that
Change thermostat.
this is obd2 trouble code table,http://www.chinasinoy.com/service/how-to-understand-trouble-codes-37.html
it can help you understand the meaning of the code, for this code, you can try this,
Verify coolant strength & level.
Verify proper cooling fan operation (check if it's running more than it should). Replace if necessary.
Verify proper engine coolant temperature (ECT) sensor operation, replace if necessary.
Verify proper intake air temperature (IAT) sensor operation, replace if necessary.
If the above items check out good, replace the thermostat.
P0128 Engine coolant temp sensor
Yep! BMW, thermostat issue.
yep, what a surprize.

roy