Appendix B:

Troubleshooting

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 harness. • 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.

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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.

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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).

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Appendix B: Troubleshooting

A B C D E F

Figure 50. Scanner™ serial port I/Os

A—Ground 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 formats: • 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

46

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™ incorrectly.

47

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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