Yamaha Waverunner VXS VX1800 Service Manual Download

Page: 296 / 318

9-5

Engine unit troubleshooting

TIP:

• Before troubleshooting the engine unit, make sure that fresh fuel of the specified type has been used.
• Check that all wiring connections are secured properly and that they are not corroded or rusty.
• Check that the engine shut-off cord is connected to the engine shut-off switch.
• Check that the battery is charged and that its specific gravity is within specification.
• Check the diagnostic code using the YDIS (or self-diagnosis) first, and then check the electronic con-

trol system by following the diagnostic code chart.

• The multifunction meter cannot display more than 1 diagnostic code. Even if multiple diagnostic codes

are present, only 1 will be displayed.

• When an ETV system (ETV, TPS, and APS) diagnostic code is detected, check the data logger of the

“ECM record data graph” as well.

• Using the YDIS is recommended because self-diagnosis may be insufficient for proper troubleshoot-

ing of the ETV system (ETV, TPS, and APS).

• If a diagnostic code is not detected, check the engine unit according to “Engine unit troubleshooting

(diagnostic code not detected)”.

• When deleting the diagnosis record on the YDIS, make sure to check the time that the diagnostic

codes were detected.

• When checking the input voltage of a part, the coupler or connector must be disconnected. As a re-

sult, the ECM determines that the part is disconnected and a diagnostic code is detected. Therefore,
make sure to delete the diagnosis record after checking the input voltage.

Using the YDIS for engine unit troubleshooting

TIP:

• Use the diagnostic codes displayed by the YDIS to check each part according to the “Diagnostic code

and checking step” table.

• Delete the diagnostic codes after checking, repairing, or replacing a part, and check that the diagnos-

tic codes are not detected again. If the same diagnostic codes are detected, the ECM may be faulty.

• Check the items listed in the table. If all the items are in good condition, delete the diagnostic code,

and then check the diagnostic codes again. If the same diagnostic codes are detected again, the ECM
is faulty.

• A breakdown of the engine symptoms are described in the “Diagnostic code table”, however, multiple

malfunctions that have been duplicated cannot be limited to these items. The symptoms may change
depending on the operating conditions and other conditions.

• Even though this model is not fitted with OBD-M function, SPN (Suspect Parameter Number) codes

will be displayed on the computer screen when YDIS version 2.20 is connected to the computer.

Self-diagnosis

If a sensor malfunction or a short circuit is detected while the engine is running, the “WARNING” indi-
cator light “a” and the check engine warning indicator “b” blink and the buzzer sounds intermittently for
30 seconds.
When the engine is stopped after the check engine warning is activated, the information display will in-
dicate a diagnostic code “c”.