Derbi boulevard 125 4t Workshop Manual page 71

Electrical system
To avoid disturbances in the ignition system during start-up, it is very important that the engine-chassis
ground connection bonding is efficient.
No spark plug
When noticing no spark plug proceded as follows:
- Pick-Up inspection.
Detach the ECU connector and check for continu-
ity between terminals 2 (Green) and 8 (Black).
The inspection must include the pick-up and it's
power cable.
If an open circuit is found, repeat the inspection
between the flywheel connector and earth. If un-
acceptable values are found, proceed by replacing
the pick-up, otherwise repair the cable.
Electric characteristic
Pick-up resistance value
Pick-up resistance value: 105 ÷ 124 Ohm
- H.T. coil primary circuit inspection
Detach the connector from the ECU and check for
continuity between terminals 3 (purple) and 8
(black) (see figure).
If unacceptable values are found, repeat the in-
spection directly from the positive and negative
terminals of the H.T. coil primary circuit.
If the values are within the prescribed limit, pro-
ceed by repairing the wiring or reattaching all wir-
ings, otherwise replace the H.T. coil.
Electric characteristic
High voltage coil primary resistance value
High voltage coil primary resistance value: 0.4 ÷
0.5 Ohm
- HV coil secondary check
Disconnect the spark plug cap from the HV cable and measure the resistance between the HV cable
terminal and the HV coil negative terminal (see figure).
If non-conforming values are measured, replace the HV coil. To carry out a more complete diagnosis,
check the peak voltage with the multimeter adaptor.
Specific tooling
ELE SYS - 71