Voltage supply for SCR control unit
Switch off the ignition with the starter key, wait for 90 seconds and then switch it on again. If the fault code remains inactive, delete the fault code.If the fault code remains and fault code 5657 has not been generated at the same time, check the voltage supply to the main unit.If the fault is in the main unit, the main unit must be renewed.
What you'll see
No driver-visible symptom recorded.
System reaction
No system-reaction text recorded.
Diagnostic depth
The SCR control unit switches off too early. The power from the SCR system has been cut off before a system shutdown has been completed.
If the vehicle has a master switch (common in buses and ADR vehicles), the fault code may be set if the master switch is used within 90 seconds of the key having been switched off.There may be a fault on the voltage supply to the SCR system.The fault may also be due to an internal fault in the control unit.If fault code 5657 is generated at the same time, the fault is probably not in the SCR system.