Volkswagen Golf / Golf GTI / Jetta. Manual — part 105

01-1

On Board Diagnostic (OBD)

On Board Diagnostic (OBD) features

The Motronic Engine Control Module (ECM)

-J220- is equipped with a DTC memory.

If Diagnostic Trouble Codes (DTCs) occur in

the sensors and components being
monitored, they will be stored in the DTC
memory together with an indication of the
type of malfunction.

After evaluating the information the Motronic

Engine Control Module (ECM) -J220-
decides between the different Diagnostic
Trouble Codes (DTCs)

DTC table from

Page 01-30

and stores these until the

contents of the DTC memory are erased.

Diagnostic Trouble Codes (DTCs) which

only occur sporadically will have the
addendum "sporadic fault" on the print out.
These Diagnostic Trouble Codes (DTCs) will
be indicated on the display by the
addendum "/SP". The cause of sporadic
Diagnostic Trouble Codes (DTCs) can be
e.g. a loose terminal or a brief open circuit. If
a "sporadic malfunction" does not occur
again within 40 warm-up phases (engine
start below 50 C coolant temperature -
switched off above 72 C), it will be erased
from the DTC memory.

The Diagnostic Trouble Codes (DTCs)

stored can be read-out with the VAG 1551
scan tool, the vehicle system tester VAG
1552 or the vehicle diagnostic, testing and
information system VAS 5051

Page 01-

23

.

On Board Diagnostic (OBD)

01-2

The DTC memory must be erased after the

malfunction(s) have been repaired

Page

01-23

and the readiness code must be

regenerated

Page 01-149

.

All Motronic Engine Control Module (ECM) -

J220- learned values will be erased when
the Motronic Engine Control Module (ECM)
-J220- connector is pulled off or the battery
is disconnected. However the contents of
the DTC memory are retained. When the
engine is subsequently started the idling
could be rough for a brief period. In this
case leave the engine running for a few
minutes at idle or perform a longer road test,
until the learning process is completed.
Procedure after voltage supply has been
interrupted

Page 24-170

.

Note:

General information for On Board Diagnosis

(OBD) can be found in the instruction
manuals for the VAG 1551 scan tool,
vehicle system tester VAG 1552 or VAS
5051.

On Board Diagnostic (OBD)

01-3

Electronic Power Control
(EPC) Warning Light -K132-

"EPC" is the abbreviation for
Electronic Power Control.

Location of Electronic Power Control

(EPC) Warning Light -K132-

When the ignition is switched on the
Motronic Engine Control Module
(ECM) -J220- checks all components
which are important for the correct
functioning of the Electronic Power
Control.

If malfunctions are detected in
Electronic Power Control system
when the engine is running, the
Motronic Engine Control Module
(ECM) -J220- will switch on the
Electronic Power Control (EPC)
Warning Light -K132-. (Diagnostic
Trouble Codes (DTCs) are identified
accordingly in the DTC table).
Simultaneously an entry is made in
the Motronic Engine Control Module
(ECM) -J220- DTC memory.

Functional check:

If the Electronic Power Control
(EPC) Warning Light -K132- does
not light-up with ignition switched
on:

Repair Manual, Electrical

Equipment On Board Diagnostic
(OBD),Repair Group 01

- Switch on ignition:

Electronic Power Control (EPC)

Warning Light -K132- must light-
up.

- Check instrument cluster and

Electronic Power Control (EPC)
Warning Light -K132-:

On Board Diagnostic (OBD)

01-4

If the Electronic Power Control (EPC) Warning

Light -K132- lights up with ignition switched on:

- Start engine and run at idle:

The Electronic Power Control (EPC) Warning

Light -K132- must go out after several seconds.

If the Electronic Power Control (EPC) Warning

Light -K132- does not go out:

- Check DTC memory, repair Diagnostic Trouble

Codes (DTCs) if necessary and then erase DTC
memory

Page 01-23

, DTC memory, checking

and erasing.

- Read off readiness code

Page 01-146

. If the

DTC memory has been erased or the Motronic
Engine Control Module (ECM) -J220- was
disconnected from battery (B+) positive, the
readiness code must be generated again

Page 01-149

.

On Board Diagnostic (OBD)