VOLVO
ECM-5840 - Engine control module (ECM). Faulty check sum
System
Engine Control Module (ECM)
Volvo models this fault code applies to
Applies to the following models:
3 modelsC30 (2007–2013), S40 (2004–2013), V50 (2004–2013)
What does this fault code mean?
The code is set when the engine control module (ECM) finds a fault while the optimisation parameters for the injectors are being programmed, for example an interrupted communication, a wrong checksum or an invalid value. Engine torque may then be limited, and a message is shown in the display. Correcting the fault is a workshop task.
Possible causes
- Communication fault during programming
- Fault while programming the optimisation parameters
- Wrong checksum
- Invalid value entered during programming
What you can do
- 1Have a workshop reprogram the optimisation parameters for the injectors
- 2Clear the code only once it has been fixed, then road test to confirm the engine runs normally
Symptoms you may notice2
- The car may lack power, hesitate or surge, for example when accelerating or pulling away
- A message and a warning symbol are shown in the display
What the fault can affect1
- Engine torque may be limited
General guidance for car owners. Diagnosis on the car can point to a different cause.