The P3173 DTC is set by the VCM when the OBC detects a fault and notifies the VCM. In this case the fault is likely related to whatever caused the B2840. There are 4 cases within the B2840, designated A,B,C,D in the Factory Service Manual, but seem to be numerical -01,02,03,04 on the OBD scan tool.
The FSM gives some voltage and current and timing conditions which can throw this code, but it is all quite useless without going into detail of which circuit to check or how to fix the problem.
B2840 DTC DETECTION LOGIC
CAUTION: Never use extension cables to charge the battery.
NOTE: DTC “B2840” may be detected by the use of extension cables for normal charging of Li-ion battery.
DTC detecting condition
A
ON BOARD CHARGER (General electrical mal- function)
• Duringnormalcharging,thePFCoutputvoltagein the on-board charger is 412 V or more for 0.1 second
or more, or 345 V or less, for 11 seconds or more.*1
• Duringnormalcharging,thePFCoutputvoltagein
the on-board charger is 450 V or more for 1 second
or more, or 345 V or less, for 11 seconds or more.*2
• Duringnormalcharging(100V),theon-boardcharg-
er DC output current is 10A or more for 5 seconds or
more.
• Duringnormalcharging(200V),theon-boardcharg-
er DC output current is 18 A or more for 5 seconds or
more.
• Duringnormalcharging(100V),theon-boardcharg-
er DC output current is abnormally lower than the on- board charger command current value for 5 seconds or more.
• Duringnormalcharging,theDCvoltageoutputbythe on-board charger is 440 V or more, or 240 V or less for 5 seconds or more.
• Duringnormalcharging,thePFCcircuitintheon- board charger operated however an abnormal status is continued for 1 second or more.
B
ON BOARD CHARGER (Component internal mal- function)
• Whennormalchargingisstarted,aDCvoltageoutput by the on-board charger of 460 V or more is detected.
• Duringnormalcharging,theDCvoltageoutputbythe
on-board charger is 200 V or less for 10 seconds or
more.
• Duringnormalcharging,theACvoltageinputintothe
on-board charger is 293 V or more for 5 seconds or
more.
• Duringnormalcharging,amalfunctionisdetectedin
an on-board charger internal circuit.
• Duringnormalcharging,theACcurrentinputintothe
on-board charger is 22 A or more for 5 seconds or more.
C
ON BOARD CHARGER (Component or system over temperature)
During normal charging, abnormal high temperature of an on-board charger internal circuit is continued for 100 seconds or more.
D
ON BOARD CHARGER (Parametric)
Ripple amplitude in output voltage of the on-board charger remains extremely large for 5 seconds or more during normal charge.
DTC
Possible cause
B2840
On-board charger
• ACpowersupply O • EVSE
• On-boardcharger