VOLVO
ECM-21AC - Long-term fuel trim load, bank1. Upper limit
System
Engine Control Module (ECM)
Volvo models this fault code applies to
Applies to the following models:
4 modelsC30 (2007–2013), C70 (2006–2013), S40 (2004–2013), V50 (2004–2013)
Show models by year and engine (9)
- Volvo C30 (2007–2013)2007Engine B5254T3 only
- Volvo C30 (2007–2013)2008–2013Engine B5254T7 only
- Volvo C70 (2006–2013)2006–2007Engine B5254T3 only
- Volvo C70 (2006–2013)2008–2013Engine B5254T7 only
- Volvo S40 (2004–2013)2005–2007Engine B5254T3 only
- Volvo S40 (2004–2013)2008Engine B5254T3, B5254T7 only
- Volvo S40 (2004–2013)2009–2012Engine B5254T7 only
- Volvo V50 (2004–2013)2005–2007Engine B5254T3 only
- Volvo V50 (2004–2013)2008–2012Engine B5254T7 only
What does this fault code mean?
The long-term fuel trim in the lower and upper part-load ranges has reached its upper limit, so the engine control module has had to add a lot of extra fuel. The fault can come from too high an ethanol content in the fuel, an air leak in the exhaust, low fuel pressure or a damaged oxygen sensor. The code is set only under certain driving conditions.
Possible causes
- Too high an ethanol content in the fuel
- Air leakage in the exhaust system
- Low fuel pressure
- Damaged oxygen sensor
What you can do
- 1Ask whether the car has recently been refuelled, and whether the fuel may have been wrong for it, since too high an ethanol content can cause the code
- 2Check the exhaust system for leaks at joints and seams
- 3Have a workshop measure the ethanol content of the fuel and the fuel pressure, as this needs measuring equipment
- 4Have a diagnostic tool? Read the long-term fuel trim in live data during a test drive and see whether it sits close to its upper position
- 5If no sign of wrong fuel is found and the fault remains, have a workshop replace the oxygen sensor
Symptoms you may notice1
- The malfunction indicator lamp (MIL) comes on
General guidance for car owners. Diagnosis on the car can point to a different cause.