Proportional valve, retarder (Y1)
â–¶ How to fix
Check the signal to pin 6 in the connector for the gearbox control unit. Check the retarder proportional valve. Check connectors and connections according to the circuit diagram for the ZF automatic gearbox, refer to group 16.
What you'll see
No driver-visible symptom recorded.
System reaction
No system-reaction text recorded.
Diagnostic depth
Detection
Incorrect signal from the retarder proportional valve.
Possible cause
The gearbox control unit, pin 6, has detected an open circuit in the wiring to the retarder proportional valve.The voltage has exceeded 4.5 V.