Yamaha XV19SX(C), Service Manual, Page: 448 / 494

FUEL INJECTION SYSTEM
7-57
Fault code No. 42 Symptom A. No normal signals are received from the speed sensor.
B. Open circuit is detected in the neutral switch.
Diagnostic code No. A 07 Speed sensor
B 21 Neutral switch
Order Item/components and probable
cause
Check or maintenance job Reinstatement
method
A-1 Connections
• Speed sensor coupler
• Main wire harness ECU coupler • Check the coupler for any pins
that may be pulled out.
• Check the locking condition of
the coupler.
• If there is a malfunction, repair it
and connect the coupler se-
curely.
Starting the en-
gine, and acti-
vating the
vehicle speed
sensor by oper-
ating the vehi-
cle at 20 to 30
km/h.
A-2 Open or short circuit in speed sensor
lead. • Repair or replace if there is an
open or short circuit.
• Between speed sensor coupler
and ECU coupler.
(blue–blue)
(white/yellow–white/yellow)
(black/blue–black/blue)
A-3 Gear for detecting vehicle speed has
broken. • Replace if defective.
Refer to “TRANSMISSION” on
page 5-112.
A-4 Defective speed sensor. • Execute the diagnostic mode.
(Code No.07)
• Replace if defective.
Refer to “CHECKING THE
SPEED SENSOR” on page
7-89.