BCM Code B410: Charging System Circuit: Notes

The generator (alternator) has fault detection capability built into the regulator. BCM will supply 12 volts to regulator over circuit No. 225 ("L" terminal) and monitor field voltage of generator by using a PWM signal over circuit No. 23 ("F" terminal).

Code B410 will set if there is either an open or short to ground on circuits No. 23 and 225, a belt break, or if an undervoltage or overvoltage condition exists. If there is a short to ground on circuit No. 225, BATTERY NO CHARGE telltale light will illuminate on IPC.

NOTE: Test numbers refer to test numbers on diagnostic chart.

Test Number 1) BCM input Code BI51 displays generator voltage as HI or LO depending on voltage state at BCM. Normally, with ignition on and engine off, circuit No. 225 will be pulled low by generator and BI51 will read LO.

Test Number 2) Check to see if LO reading is due to circuit No. 225 or generator. If reading changes from LO to HI when generator is disconnected, circuit No. 225 and BCM are okay.

Test Number 3) Determines if fault is due to BCM or circuit No. 225.

Test Number 4) BCM parameter BD51 displays amount of generator field activity. Under normal conditions, a reading less than 7 percent would indicate a fault in field circuit or BCM.

Test Number 5) Removing generator connector will determine if fault is due to generator or an open in circuit No. 225 including BCM and interface connector.