Yamaha XP500 Service Manual page 302

• [C] Determining the cause and location of the malfunction
• [C-1] Only the ABS warning light does not come on when the main switch is set to "ON"
NOTE:
_
Check following the steps in sequence.
1. Visual check
1) Check the ABS fuse.
Determine the cause of the blown fuse and repair. Replace with a new fuse. (Refer to "CHECK-
ING THE FUSES" in chapter 3.)
2) Check the wire harness (ABS system circuit) couplers.
Check that the wire harness (ABS system circuit) couplers are securely connected.
3) Check the connection of the wire harness (ABS system circuit) to the ECU (ABS).
Check that the wire harness (ABS system circuit) is securely connected to the ECU (ABS).
2. Confirmation using the test coupler adaptor
1) Connect the test coupler adaptor to the test coupler. (Refer to "[B-5] ABS malfunction check
using the ABS self-diagnosis (present malfunction)".)
2) Ground the warning light terminal (white/red) of the test coupler adaptor or connect the warning
light terminal to the negative battery terminal.
• If the ABS warning light comes on, the wire harness (ABS system circuit) may be disconnected.
• If the ABS warning light does not come on, the ABS warning light lead may be disconnected or
the contact of the ABS warning light may be defective.
3) Remove the ECU (ABS) coupler and check the ECU (ABS) coupler and test coupler adaptor
ends of the white/red lead for continuity.
• If there is continuity, the ECU (ABS) is defective. → Replace the ECU (ABS). (Refer to "[D-1]
Maintenance of the ECU (ABS)".)
• If there is no continuity, the warning light circuit in the wire harness (ABS system circuit) is defec-
tive. Disconnection or short → Correct. (Refer to "CIRCUIT DIAGRAM".)
• [C-2] ABS warning light and all other indicators do not come on
NOTE:
_
Check following the steps in sequence.
1. Check the power supply system.
1) Check that the battery is connected correctly.
2) Check the battery voltage. (Refer to "CHECKING AND CHARGING THE BATTERY" in chapter
3.)
3) Check if the main fuse is blown. If the main fuse is blown, determine the cause and repair.
Replace with a new fuse. (Refer to "CHECKING THE FUSES" in chapter 3.)
2. Check the connections.
1) Check that the main fuse coupler is securely connected.
2) Check that the wire harness (ABS system circuit) is securely connected.
3) Check that the main switch coupler is securely connected.
4) Check that the meter assembly coupler is securely connected.
When these checks are finished, return to [A] and check the ABS again.
ANTI-LOCK BRAKE SYSTEM (XP500A)
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