Sym GTS 250 Service Manual page 219

2). Check procedure:
a). Connect the diagnostic to the vehicle through the connector onboard.
b). Key-on but don't start the engine.
c). Check if the connection between ECU and Diagnostic is good.
d). We can check the ECU ID number by the following figure 2.
e). Check if the model number and the software version of ECU are both correct.
f). Check if there is any trouble code in the Diagnostic. If yes, please erase it.
g). Start the engine.
h). Check for the parameters in the Diagnostic to see if they are all in normal range.
Figure 2
3). Malfunction determination:
a). ECU ID correct
b). Trouble code can be erased and won't show up again after re-start.
4). Abnormal phenomenon and treatment:
a). Unable to connect→ Check the Diagnostic if any error, then check the ECU by replacing
another new one.
b). Unable to start→ Check the perimeter parts and ECU for error.
c). Trouble code appears→ Check the perimeter parts and ECU for error. Check the
malfunction reason and re-confirm.
4