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

03:02-03

Issue 2 en

EDC MS5 in-line injection pump

Fault diagnosis

1 585 749

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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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

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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