Subaru B9 Tribeca 2011–2013 — technical service bulletin
Bulletin 1111112R · NHTSA communication 10234269 · issued Dec 6, 2012
Technical service bulletin
communication type
Engine and Engine Cooling
component
2011–2013
model years
9
vehicle entries
Official summary
If you encounter a vehicle which has P0128 stored in memory, it may be caused by a very slight variation in coolant temperature between the left and right cylinder bank.
Vehicles covered
What a TSB means. Technical service bulletins are repair guidance manufacturers send to dealers — they are not recalls, and repairs are not automatically free (warranty extensions are an exception worth checking). The full document is available via NHTSA’s vehicle lookup.