VOLVO
ECM-21FB - Long-term fuel trim, bank 2. Signal missing
System
Engine Control Module (ECM)
Volvo models this fault code applies to
Applies to the following models:
2 modelsS80 (1999–2006), XC90 (2003–)
Show models by year and engine (2)
What does this fault code mean?
The fault concerns fuel adaptation on bank 2, even though the code is named signal missing. It is only set once an underlying adaptation code has been stored in two consecutive driving cycles, and it is always present together with one of them.
Possible causes
- Consequential fault from an underlying fault code for adaptive lambda regulation on bank 2
What you can do
- 1Start by fixing the root fault among the bank 2 adaptation codes, since this code has no fault-tracing of its own
- 2Have a diagnostic tool? Read the codes and see which bank 2 adaptation codes are stored next to this one
- 3Clear the code only after the underlying faults are fixed, and road test to check that it does not return
Symptoms you may notice1
- The engine warning lamp comes on or behaves abnormally
General guidance for car owners. Diagnosis on the car can point to a different cause.