Appendix B - Snap-on

Appendix B - Snap-on
Appendix B:
Startup Troubleshooting
If the display does not light up when you use the Quick ID
button or connect the Scanner™ to vehicle power, check:
• The Scanner™ battery, located under the left handgrip.
• For a blown cigarette lighter fuse on the vehicle if using
the cigarette lighter power cable.
• For bent or broken pins on both ends of the data cable
and on the test adapter.
• For a loose cable connection.
• For an open ground wire in the vehicle connector wiring
• For correct connection at the battery if you are using the
battery power adapter.
Replace the internal battery if the Scanner™ operates
erratically in any way when you use the Quick ID button or if
recorded data is not retained in Scanner™ memory.
If the display is very dim or virtually blank when you apply
power to the Scanner™, disconnect the Scanner™ from
vehicle power and remove the internal 9-volt battery from
under the handgrip. Hold down the Quick ID button for 5
seconds to clear Scanner™ memory. Then, reinstall the
9-volt battery.
If one or more segments of the display do not light during the
display check, you may not get valid readings when viewing
vehicle data or performing functional tests.
If the Scanner™ displays incomplete characters, remove the
cartridge and carefully clean the edge connector with a Pink
Pearl® pencil eraser, or equivalent. Wipe off eraser dust with
a clean cloth.
Appendix B: Troubleshooting
Low Internal Battery Voltage
If the internal battery is low, but still has enough power to
light the display, or if you are using a Power Pac with a low
charge, you will see a message similar to Figure 47.
Figure 47. Voltage low message
If the battery is very low but still has enough power to light
the display, the low-voltage message may appear when you
press the Quick ID button. In this case, replace the battery
immediately or you cannot use the Quick ID button. Also,
Custom Setup selections and recorded data may be lost
when the Scanner™ is disconnected from the vehicle.
Power Interruption
If vehicle power is interrupted at any time during testing, the
Scanner™ briefly repeats the display check and the
2-second copyright message. It then displays the vehicle
identification message shown previously. Your choices are
the same in all cases:
• Press Y to return to the Main Menu and continue testing.
• Press N to enter a new vehicle identification.
If Scanner™ power drops too low during cranking or during
some other repeatable condition on a particular vehicle, the
Scanner™ again resets to the display check. To keep the
Scanner™ from resetting, hold down the Quick ID button as
an auxiliary power source during conditions that cause
resetting on a specific vehicle. The MT2500-600A Super
Power Pac may also be used for auxiliary power.
Problems With Printer, Displays, and Other Remote Terminals
Problems With Printer, Displays, and Other
Remote Terminals
This section gives information for diagnosing
communication problems between the Scanner™ and the
printer, display, or other remote terminal. If you suspect a
communication problem, follow these tips:
After sending a Print Screen or Print Frame command to the
printer, the Scanner™ should briefly display a printing
message (Figure 48).
Figure 48. Printing message screen
The Scanner™ then returns to the previous menu. If there is
a problem, the Scanner™ displays a printer not responding
message (Figure 49).
Figure 49. Printer not responding screen
If the printer is “ready,” the above message usually indicates
a cable problem. Only the Seiko printer and the Snap-on
printer cables are recommended for Scanner™ use. Other
printers may require a custom printer cable.
The Scanner™ serial port is a 6-position modular (RJ-11)
receptacle (Figure 50).
Appendix B: Troubleshooting
Figure 50. Scanner™ serial port I/Os
B—CTS (clear to send)
C—RXD (data to Scanner™)
D—TXD (data from Scanner™)
E— RTS (request to send)
F— +12 V (battery volts)
The Scanner™ serial port transmits data in the following
• 8 data bits
• 1 stop bit
• No parity
• Baud rates: 19200, 9600, 4800, 2400
• XON = 17 (011H)
• XOFF = 19 (013H)
If you are sending a print command to a display or other
remote terminal, the “printer not responding” message
usually indicates a cable problem. Only Snap-on® cables
should be used.
If print commands are sent successfully, the printed or
displayed data should replicate what is displayed on the
Scanner™ screen. Illegibly printed or displayed data
indicates an incorrect baud rate. Refer to the printer, display,
or other remote terminal manufacturer's baud rate
Vehicle Communication Problems
specification to determine the correct baud rate. Refer to
“Communication Setup—Baud Rate Setting” on page 33 for
instructions on setting the Scanner™ baud rate.
If no data is printed or displayed, either the cable is bad, the
printer is incompatible, or the display or other remote
terminal software is not working properly.
Vehicle Communication Problems
When the screen displays a “no communication” message
(Figure 51), it means the Scanner™ and the vehicle control
module cannot communicate with each other for some
reason. Common problems that prevent a vehicle from
communicating are addressed in this section,
manufacturer-specific problems are discussed in the various
vehicle communication software manuals.
Figure 51. No Communication message
The following conditions will cause Scanner™ to display a
“no communication” message:
• You are using the incorrect Personality Key® with the
test adapter.
• You select a system for testing that the vehicle is not
equipped with (i.e., ABS).
• There is a loose connection.
• There is a blown fuse or wiring fault on the vehicle.
• The vehicle has been identified to the Scanner™
Appendix B: Troubleshooting
Check Scanner™ Operation
If the Scanner™ works properly on other vehicles from the
same manufacturer, particularly other models with the same
control system, the source of the problem is most likely in the
vehicle, not the Scanner™.
If the display fails to light up or if readings are unsteady, the
Scanner™ may be at fault.
If the display intermittently resets or goes blank, there may
be a wire opening intermittently in the data cable or in the
test adapter. Check the cable and test adapter connections.
If connections are good, check data cable continuity from pin
to pin between the D-shaped connectors at either end of the
cable with an ohmmeter (Figure 52). There should be little or
no resistance.
Figure 52. Checking continuity of the data cable
If the Scanner™ passes all the above checks, the problem is
most likely in the vehicle. Vehicle communication problems
are unique for each vehicle manufacturer. Refer to the
appropriate manufacturer test manual.
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