Operation CHARM: Car repair manuals for everyone.

Test B

PINPOINT TEST B: THE CHARGING SYSTEM WARNING INDICATOR IS ON WITH THE ENGINE RUNNING (THE CHARGING SYSTEM VOLTAGE DOES NOT INCREASE)


Test B1-B3:






Test B3-B4:






Test B5-B6:






Normal Operation
With the engine running, the charging system warning indicator is off. The sense A circuit 35 (OG/LB) to the generator field coil is 13-15 volts. The S (stator) circuit (internal to the generator) is used to feed back a voltage signal from the generator to the voltage regulator. This voltage is used by the powertrain control module (PCM) to turn off the charging system warning indicator. The battery positive output (B+) circuit 2037 (RD) is the generator output supplied to the battery and electrical system.

Possible Causes
- generator B+ circuit 2037 (RD) open or high resistance
- GEN COM circuit 586 (RD/PK) open or shorted to ground
- GEN MON circuit 585 (VT) open or shorted to ground
- generator
- PCM