Yamaha MTN850-A 2017 Service Manual page 473

Fault
Part
code
53 IMMOBILIZER
UNIT
54 IMMOBILIZER
UNIT
55 IMMOBILIZER
UNIT
56 ECU
Immobilizer system indicator light fault code indication
Digit of 10 : Cycles of 1 sec. ON and 1.5 sec. OFF.
Digit of 1 : Cycles of 0.5 sec. ON and 0.5 sec. OFF.
Example: fault code 52
a. Light on
Symptom
Codes cannot be
transmitted between
the ECU and the
immobilizer unit.
Codes transmitted
between the ECU and
the immobilizer unit do
not match.
Key code registration
malfunction.
Unidentified code is
received.
8-116
IMMOBILIZER SYSTEM
Cause
Noise interference or dis-
connected lead/cable.
1. Interference due to
radio wave noise.
2. Disconnected commu-
nication harness.
3. Immobilizer unit mal-
function.
4. ECU malfunction.
Noise interference or dis-
connected lead/cable.
1. Interference due to
radio wave noise.
2. Disconnected commu-
nication harness.
3. Immobilizer unit mal-
function.
4. ECU failure.
(The ECU or immobi-
lizer unit was replaced
with a used unit from
another vehicle.)
Same standard key was
attempted to be registered
two consecutive times.
Noise interference or dis-
connected lead/cable.
b. Light off
Action
1. Check the wire
harness and con-
nector.
2. Replace the main
switch/immobi-
lizer unit.
3. Replace the ECU.
Refer to
"REPLACING
THE ECU (Engine
Control Unit)" on
page 8-157.
1. Register the code
re-registering key.
2. Check the wire
harness and con-
nector.
3. Replace the main
switch/immobi-
lizer unit.
4. Replace the ECU.
Refer to
"REPLACING
THE ECU (Engine
Control Unit)" on
page 8-157.
Register another
standard key.
1. Check the wire
harness and con-
nector.
2. Replace the main
switch/immobi-
lizer unit.
3. Replace the ECU.
Refer to
"REPLACING
THE ECU (Engine
Control Unit)" on
page 8-157.