Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSFORD2004EXPLORER 2WD V6-4.0L VIN EREPAIR AND DIAGNOSISSTARTING AND CHARGINGCHARGING SYSTEMTESTING AND INSPECTIONPINPOINT TESTSTEST F
2004 Ford Explorer 2WD V6-4.0L VIN E
Test F
2004 Ford Explorer 2WD V6-4.0L VIN ESECTION Test F
PINPOINT TEST F: THE CHARGING SYSTEM WARNING INDICATOR FLICKERS OR IS INTERMITTENT
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 on all 4.6L vehicles and only on 4.0L vehicles built to December 8, 2003; but an external circuit 4 [WH/BK] on 4.0L vehicles built from December 8, 2003) is used to feed back a voltage signal from the generator to the voltage regulator. This voltage feedback signal (typically half the battery voltage) is used by the regulator to provide a signal to the PCM which in turn provides a signal over the CAN communication link to the instrument cluster to turn off the charging system warning indicator. The I (ignition) circuit 904 (LG/RD) is used to turn on the voltage regulator. This circuit will be 6-8 volts (C102a connected) with the key in the ON position and the engine not running. Once the engine is started, the I circuit will measure 8-10 volts (C102a connected). The battery positive output (B+) circuit 38 (BK/OG) is the generator output supplied to the battery and electrical system.
Possible Causes
- battery junction box (BJB) fuse links 290A (GY 12 GA), 290 (GY 12 GA) or 292 (BN 18 GA) intermittently open
- external stator circuit 4 (WH/BK) (if equipped) open or high resistance
- generator connections
- generator
Test F1-F3:
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 on all 4.6L vehicles and only on 4.0L vehicles built to December 8, 2003; but an external circuit 4 [WH/BK] on 4.0L vehicles built from December 8, 2003) is used to feed back a voltage signal from the generator to the voltage regulator. This voltage feedback signal (typically half the battery voltage) is used by the regulator to provide a signal to the PCM which in turn provides a signal over the CAN communication link to the instrument cluster to turn off the charging system warning indicator. The I (ignition) circuit 904 (LG/RD) is used to turn on the voltage regulator. This circuit will be 6-8 volts (C102a connected) with the key in the ON position and the engine not running. Once the engine is started, the I circuit will measure 8-10 volts (C102a connected). The battery positive output (B+) circuit 38 (BK/OG) is the generator output supplied to the battery and electrical system.
Possible Causes
- battery junction box (BJB) fuse links 290A (GY 12 GA), 290 (GY 12 GA) or 292 (BN 18 GA) intermittently open
- external stator circuit 4 (WH/BK) (if equipped) open or high resistance
- generator connections
- generator
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.