Function
It allows communication between the Marelli injection control unit, the throttle control unit and the instrument panel.
Level in wiring diagram: CAN line
Pin-out: see wiring diagram
Axone: electrical errors
U1602 CAN line without signals - Bus Off.
Error cause
No communication on CAN line (PIN 20 and/or PIN 51 VEHICLE): problem on the whole network (for example, battery cut-off or short circuited or shorted to ground).
Troubleshooting
Check the Marelli control unit VEHICLE connector: if not OK, restore; if OK, check the earth insulation of the two CAN lines from PIN 20 and PIN 51 of the VEHICLE connector: If not OK, restore the cable harness; if OK, check continuity of the two CAN lines from the Marelli control unit VEHICLE connector to the filter casing large connector and to the instrument panel connector: if not OK, restore the cable harness; if OK, check that the two lines are not shorted to positive testing each of the 3 connectors (Marelli control unit connector, filter casing large connector and instrument panel connector) with 1 connector disconnected at a time and by setting the key to ON: If not OK, restore; if OK, replace the Marelli control unit.
Mute Node CAN Line, U1601 - Mute Node
Error cause
The injection ECU cannot send CAN signals; it receives signals from the instrument panel and the throttle control unit: the control unit may need replacing.
Troubleshooting
Replace the Marelli control unit.
CAN line to instrument panel, U1701 - no signal
Error cause
No signal is received from the instrument panel.
Troubleshooting
Check the connector of the instrument panel: if not OK, restore; if OK, check the continuity of the two lines from the instrument panel connector to the VEHICLE connector of the Marelli control unit: if not OK, restore the cable harness; if OK, replace the instrument panel.
CAN line to the throttle control unit, U1705 - no signal
Error cause
No signal is received by the throttle control unit.
Troubleshooting
Check the filter housing large connector and the throttle control unit connector: if not OK, restore; if OK, check the continuity of the two lines from the filter housing large connector to the VEHICLE connector of the Marelli control unit: if not OK, restore the cable harness; if OK, check the continuity of the two lines from the filter housing large connector to the throttle control unit connector: if not OK, restore the cable harness; if OK, replace the throttle control unit.
Axone: logic errors
CAN Line to throttle control unit, U1706 - no message update.
Error cause
No updated signal is received from the throttle control unit.