Volvo All Engines (2004 Emissions) Fault Code: PSID 201 FMI 9 CAN1 J1939 Communication Link B

Fault Condition: Code PSID 201 will set when the Engine Management System (EMS) Module loses communication with the Vehicle Electronic Control Unit (VECU) on the J1939 data line. The fault will become inactive if communication resumes. If communication is lost on both the J1587 and J1939 data lines, the engine will still run using the idle validation switch.

Possible repairs:

1) If code PSID 201 is NOT set, wiggle the EMS Module and VECU harnesses and connectors to try to set the code. Visually inspect the EMS Module and VECU connectors and wires for poor connections.
2) Disconnect the Vehicle Electronic Control Unit (VECU) connector A. Turn the ignition key ON. Measure the voltage between Vehicle Electronic Control Unit (VECU) connector A pin 13 and a good ground. Then measure the voltage between Vehicle Electronic Control Unit (VECU) connector A pin 14 and a good ground. If the measured voltage is 0 volts, check the battery power circuit to the Vehicle Electronic Control Unit (VECU). If the measured voltage is NOT approximately battery voltage at either pin, check the battery power circuit and connectors for loose, corroded or damaged terminals and repair as necessary.
3) Disconnect the Vehicle Electronic Control Unit (VECU) connector A. Turn the ignition key ON. Disconnect the Vehicle Electronic Control Unit (VECU) connector A. Check for continuity between Vehicle Electronic Control Unit (VECU) connector A pin 12 and a good ground. If continuity does NOT exist, repair the open in the ground circuit.
4) Turn the ignition switch OFF. Disconnect the Engine Management System (EMS) Module connector B. Disconnect the Vehicle Electronic Control Unit (VECU) connector C. Check for continuity between Engine Management System (EMS) Module connector B pin 55 and Vehicle Electronic Control Unit (VECU) connector C pin 5. If continuity does NOT exist, locate and repair the open in the data line and retest the system.
5) Turn the ignition switch OFF. Disconnect the Engine Management System (EMS) Module connector B. Disconnect the Vehicle Electronic Control Unit (VECU) connector C. Check for continuity between Engine Management System (EMS) Module connector B pin 51 and Vehicle Electronic Control Unit (VECU) connector C pin 4. If continuity exists, check the Engine Management System (EMS) Module harness and all connections for loose,
corroded or damaged terminals and repair or replace as necessary. If no loose, corroded or damaged terminals are found, replace the Engine Management System (EMS) Module.
If continuity does not exists, locate and repair the open in the data line and retest the system.