Volkswagen Golf / Golf GTI / Jetta. Manual — part 251

28-24

Test requirements

Electrical Wiring Diagrams,

Electrical troubleshooting and
Component locations

The fuses must be OK.

The battery voltage must be at

least 11.5 V.

All electrical accessories, e.g.

lights and rear window defroster
must be switched off.

If the vehicle is equipped with air

conditioning, this must be
switched off.

Motronic Engine Control Module

(ECM) Power Supply Relay -
J271- must be OK., checking:

Engine speed sensor must be

OK, checking

Page 24-93

.

Camshaft Position (CMP)

Sensor must be OK, checking

Page 28-16

.

Ignition system, servicing

28-25

Test sequence

Note:

Removing fuse 29 interrupts the
voltage supply to the fuel injectors.

- Remove fuse 29 from fuse holder.

- Remove engine cover.

Note:

Mark connector and component
before disconnecting.

- Disconnect connectors from

ignition coils 1 to 6.

Ignition system, servicing

28-26

Checking voltage supply

If no voltage is present:

- Measure supply voltage between

terminals 1 and 3, and 2 and 3 of
disconnected connector using
multimeter and adapter cables
from V.A.G 1594.

- Switch on ignition.

Specification: at least 11.5 V

- Switch off ignition.

If there is no malfunction in the
supply voltage:

- Check wire for open circuit

between 4-pin connector terminal
3 and Motronic Engine Control
Module (ECM) Power Supply
Relay -J271- referring to Electrical
Wiring Diagrams.

Wire resistance: max. 1.5

- Check wiring for open circuit

between 4-pin connector and
Ground referring to Electrical
Wiring Diagrams.

terminal 1 and Ground

terminal 2 and Ground

Wire resistance: max. 1.5

- Check activation

Page 28-27

.

Ignition system, servicing

28-27

Checking activation

When the LED flickers and the
supply voltage is OK.:

- Connect VAG 1527 LED test light

using adapter cables from V.A.G
1594 to terminals 4 and engine
Ground of disconnected
connector for cylinder 1.

- Operate starter and check ignition

signal from Engine Control
Module (ECM).

LED must flicker

- Repeat check at fuel injector

connectors for Cyls. 2 to 6.

- Switch off ignition.

- Replace relevant ignition coil with

power output stage

Page 28-

3

, item 2 .

- Check DTC memory, repair

malfunctions if necessary and
then erase DTC memory

Page

01-23

.

- Read readiness code

Page 01-

146

. If DTC memory has been

erased or Engine Control Module
(ECM) was disconnected from
battery positive, readiness code
must be generated again

Page

01-149

.

Ignition system, servicing