Volvo Symptom D12D US02 Service Manual page 54

Group 20
Engine Does Not Reach Rated Speed
Difficulty reaching rated engine speed may be caused by:
•
Problems in the fuel or intake system.
•
Specific fault codes generating a response by the
engine control system.
The following checks should be performed in order until
the fault is found. These checks also can help exclude
components with no faults or malfunctions. The amount
and sequence of checks depend on results from Basic
Checks (including active or inactive fault codes noted),
vehicle conditions, vehicle service and repair history,
other symptoms, and information from the driver.
Low Power After Vehicle Repair
In case of sudden low power after a vehicle is repaired
or rebuilt, it should be determined whether the cause
is related to an engine component or a fault in another
vehicle component. Low power can also be caused by:
•
Incorrect (unauthorized) or improperly installed engine
components.
•
Engine ECU limiting engine speed or torque because
of a fault code generated by faulty or improperly
installed electrical components.
The following checks should be performed in order until
the fault is found. These checks also can help exclude
components with no faults or malfunctions. The amount
and sequence of checks depend on results from Basic
50
D
•
"Step 1: Fault Code Readings" page 59
•
"Step 2: Visual Inspection (System Checks)" page 59
•
"Step 3: VCADS Pro Tests" page 59
•
"Step 4: Component and Function Checks" page 61
"Low Power Output, Fault Tracing" page 47
Checks (including active or inactive fault codes noted),
vehicle conditions, vehicle service and repair history,
other symptoms, and information from the driver.
•
"Step 1: Fault Code Readings" page 61
•
"Step 2: Visual Inspection (System Checks)" page 62
•
"Step 3: VCADS Pro Tests" page 63
•
"Step 4: Component and Function Checks" page 64
"Low Power Output, Fault Tracing" page 47