14 © Scania CV 2011
Troubleshooting using flash codes for
the EMS control unit
• The diagnostics lamp on the instrument panel(s) always comes on for
2 seconds when the system is powered up.
• As soon as a fault is detected by the control unit, it is stored in the
EEPROM fault code memory and the diagnostics lamp on the
instrument panel(s) comes on.
• The diagnostic lamp will stay on for as long as a fault is active. Even if
the lamp has gone off and the fault is no longer active, the code can
generally be read off by following the instructions below.
Reading off control unit fault codes
1. Switch on the 15-supply.
2. Activate the diagnostics switch to the left to view the flash codes for the
control unit (EMS).
3. A fault code will then flash on the diagnostic lamp. This flash code
consists of long flashes (approximately 1 second long) and short flashes
(0.3 seconds long). Long flashes are equivalent to units of 10, and short
flashes are equivalent to
units of 1.
Example: long - short - short = fault code 12.
4. Repeat this procedure until the first flash code is repeated. This means
that the entire fault code memory has been flashed out. If the fault code
memory is empty, only one long flash approx. 4 seconds long will be
given.
5. See the flash code table on the next page for a description and to locate
the fault.
6. In order to obtain further information about the fault code, the PC-based
diagnostics tool or Scania EMS display must be used. Contact an
authorised Scania workshop.
7. When a fault has been rectified the fault code can be cleared as
described below.
Clearing fault codes
1. Switch off the 15-supply. If dual instrumentation has been fitted, the
15 voltage must be switched off on both panels.
2. Activate the diagnostics switch in the same direction as the flash codes
indicate, i.e. to the right for the coordinator (COO) or to the left for
EMS.
3. Switch on the 15 voltage and at the same time keep the diagnostics
switch activated, to the right (COO) or to the left (EMS), for 3 seconds.
4. This will erase passive fault codes which can be read via flash codes for
the relevant system. The rest of the fault codes will remain in the
EEPROM and can only be deleted using the PC tool.
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