Scania EDC MS5 in-line injection pump Fault diagnosis(1).pdf

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EDC MS5 in-line injection pump
Fault diagnosis
1 585 749
© Scania CV AB 1998-03, Sweden
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Contents
Diagnosing faults with the
diagnostics lamp
General............................................................ 3
Interviewing the driver ................................... 4
Fault codes ...................................................... 4
Wiring diagrams ............................................. 4
Faults that do not generate fault codes ........... 4
Accessing the fault codes................................ 5
Erasing the fault codes.................................... 6
List of fault codes
........................................................................ 7
Control unit connections
...................................................................... 37
Wiring diagrams
Current circuit diagrams, 12 engine.............. 42
Current circuit diagrams, 14 engine.............. 49
Location of electrical components Location of components, 12 engine.............. 41
Location of components, 14 engine.............. 48
Faults that do not generate fault
codes
...................................................................... 56
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© Scania CV AB 1998, Sweden
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General
EDC
Diagnosing faults with the
diagnostics lamp
• The fault code texts have been taken directly from the PC program Scania Diagnos
and are given here in their original form to avoid confusion.
• Suggestions are made in the text as to how each fault may be dealt with.
• The fault code texts conclude with references to the current circuit diagrams in the
”Wiring diagrams” section. This section also contains diagrams showing the loca-
tions of the electrical components.
• Further information on how the EDC system is connected to the various electrical
systems in the vehicle is given in the connection diagrams in Group 16.
• Faults that do not cause fault codes to be generated are included in the section
headed ”Faults that do not generate fault codes”.
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Fault diagnosis
Interviewing the driver
Wiring diagrams
Begin fault diagnosis by interviewing the
driver. Try to get an overall picture of the
problem. Ask about the following:
The fault code texts conclude with references
to current circuits. These current circuits refer
to the current circuit diagrams in the ”Wiring
diagrams” section.
- Fault symptoms
- Under what conditions the fault arose
- How often the fault has arisen
- If the warning lamp came on
- If the warning lamp went out by itself
- If the driver has erased fault codes
The diagrams for the 12 and 14 engines are
shown individually and in unbroken sequence.
Each section starts with a drawing which
shows the location of components.
Further information as to how the EDC system
is connected to the vehicle’s electrical system is
shown in the connection diagrams in Group 16.
Fault codes
Faults that do not generate
fault codes
Access all the fault codes stored in the mem-
ory. Compare them and attempt to reach a con-
clusion as to the probable cause of the fault
before taking any further action. Fault codes
are stored in the order in which they were
registered.
Although the control unit software is advanced
and anticipatory, a fault may arise which the
control unit cannot distinguish from something
that can occur during the course of normal
operation. In such case, no fault code will be
generated; there is always a limit to how exten-
sively a function can be monitored. A table of
various faults with their symptoms and causes
is given in the section headed ”Faults that do
not generate fault codes”.
Remember that the kind of faults which can arise
in a fuel system without EDC, such as defective
injectors, can also arise in EDC vehicles.
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Accessing the fault codes
Accessing the fault codes
The power should be switched on with the
starter key.
1 Press the diagnostics switch and count the
number of flashes.
2 Press the switch again and count the number
of flashes. If the same code is repeated,
there is only one fault in the system. If more
than one code is shown, continue to press
the button until the first code is displayed
again. Note all the fault codes.
1 2
1 Diagnostics switch
2 Diagnostics lamp
The long flashes (1 second) that appear first rep-
resent tens, the short flashes (0.3 second) that
follow are units.
The example to the right displays fault code 25.
A single long flash (4 seconds) means that there
are no fault codes in the memory.
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