Control Functions - Volvo 240 1989 Service Manual

Fault tracing
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Fuel sysrem LH2.4 - 240
Control function 1
The diagnostic system carries out continuous ctlecks
of the fuel system during engine operation.
Any fuet system fau lts are stored in the diagnostic
system's memory as a fault code. The system can
identify and store seventeen different fa ult codes.
There is also a code to indicate that the fuel system
is co mpletely OK.
Up to three fault codes can be stored in the memory
simultaneo usly .
Once the engine stops, the fault codes can be read by
counting the flash series at the diagnostic socket
diode.
Control function 2
This tunction tests the various fuel system breakers .
As each one is activ ted. functions information is
provided by the diagnostic socket diode in the form of
ftash series.
The functions test is generally used aHer such activi ­
ties as repairs to check that certain controls are
connected and operating correctly .
Control function 3
This test is carried with the engine off . It tes ts the
adjustment functions of the fuel system.
In this case, the test consists of initiating an functions
cycle whereby the diagnostic system activates cer ­
tain control components .
You find out
if
the component is operating correctly
either by placing YOtI, hand on the component or by
listening for the click which occurs when the compo­
nent is activated.
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