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.
SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSFORD2004EXPLORER 2WD V6-4.0L VIN EREPAIR AND DIAGNOSISSTARTING AND CHARGINGCHARGING SYSTEMTESTING AND INSPECTIONPINPOINT TESTSTEST D
2004 Ford Explorer 2WD V6-4.0L VIN E
Test D
2004 Ford Explorer 2WD V6-4.0L VIN ESECTION Test D
PINPOINT TEST D: THE CHARGING SYSTEM WARNING INDICATOR IS ON WITH THE ENGINE RUNNING AND THE BATTERY INCREASES VOLTAGE
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 is 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 powertrain control module (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
- I circuit 904 (LG/RD) open or shorted to ground
- external S (stator) circuit 4 (WH/BK) (if equipped) open or high resistance
- instrument cluster
- generator
- PCM
Test D1:
Test D2-D4:
Test D5:
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 is 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 powertrain control module (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
- I circuit 904 (LG/RD) open or shorted to ground
- external S (stator) circuit 4 (WH/BK) (if equipped) open or high resistance
- instrument cluster
- generator
- PCM
RENDER: 1.0x
NO RELATED
Recommended Tools & Savings
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
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.