Charging System - General Information: Overview Ford Explorer IV

Principles of Operation

After the engine is started, voltage is applied through the I (ignition) circuit CDC09 (YE) from the PCM to the voltage regulator. This turns the regulator on, allowing current to flow from the A (battery sense) circuit SDC02 (RD) to the generator field coil. At this time, the generator begins to generate current, which is then supplied to the vehicle electrical system through the output (B+) terminal of the generator.

Once the generator begins generating current, a voltage signal is taken from the generator stator and fed back to the regulator. This voltage feedback signal (typically half the battery voltage) is used by the regulator to provide a signal to the PCM. This, in turn, provides a signal over the controller area network (CAN) communication link to the instrument cluster (IC) to turn off the charging system warning lamp. This indicates the charging system is operating properly. The S (stator) circuit is internal to the generator on 4.6L applications, but is an external circuit VDC42 (GN) on 4.0L applications.

With the system functioning normally, the generator output current is determined by the voltage of the A circuit SDC02 (RD). The A circuit SDC02 (RD) voltage is compared to a set voltage internal to the regulator. The regulator controls the generator field current to maintain the correct generator output.

The set voltage varies with temperature and is typically higher in cold temperatures and lower in warm temperatures. This allows for better battery recharge in the winter and reduces the possibility of overcharging in the summer.

This is a System 2 charging system, which uses a PCM-controlled I (ignition) circuit to the generator regulator, circuit CDC09 (YE). System 2 charging systems are virtually identical in design and therefore, share the same diagnostics. The circuit numbers and colors may be different, but the functions are the same. System 2 charging systems may use any type of generator, as the generator type usually depends on the engine packaging and/or output requirements versus cost.

Normal Operation

The generator output is supplied through the positive battery output (B+) circuit SDC02 (RD) terminal on the rear of the generator to the battery and electrical system. During normal operation the charging system warning indicator is off with the key in the ON position and the engine running. The charging system warning indicator is on with the key in the ON position and the engine off.

This pinpoint test is intended to diagnose the following

1. Circuit SDC02 (RD) high resistance
2. Positive battery cable high resistance
3. Negative battery cable high resistance
4. High key-off current drain(s)
5. Battery
6. Generator

Scheme 4

Scheme 5

1. A1 CHECK THE BATTERY CONDITION Carry out the Battery - Condition Test to determine if the battery can hold a charge and is OK for use. Refer to «BATTERY, MOUNTING AND CABLES»(ref-270948) . Does the battery pass the condition test? YES : Go to A2 . NO : INSTALL a new battery. REFER to «BATTERY, MOUNTING AND CABLES»(ref-270948) . TEST the system for normal operation.
2. A2 CHECK THE GENERATOR OUTPUT Carry out the Generator On-Vehicle Load Test and No Load Test. Refer to «Component Tests»(ref-270936-S19756324322007110700000) . Does the generator pass the component tests? YES : Go to A3 . NO : INSTALL a new generator. REFER to «GENERATOR AND REGULATOR»(ref-270906) . TEST the system for normal operation.
3. A3 CHECK FOR CURRENT DRAINS Carry out the Battery - Drain Test. Refer to «Component Tests»(ref-270936-S19756324322007110700000) . Are any circuits causing excessive current drains? YES : REPAIR as necessary. TEST the system for normal operation. NO : Go to A4 .
4. A4 CHECK THE VEHICLE GROUNDS Key in START position. Measure the voltage drop between the generator housing and the negative battery terminal. Is the voltage drop less than 0.1 volt? YES : Go to A5 . NO : CHECK the engine ground, generator ground and the battery ground for corrosion. TEST the system for normal operation.
5. A5 CHECK THE VOLTAGE DROP IN B+ CIRCUIT SDC02 (RD) Measure the voltage drop between the generator C102b (4.0L), C1104b (4.6L), circuit SDC02 (RD) and the positive battery terminal. Is the voltage drop less than 0.5 volt? YES : CHECK if the customer left any component(s) on or if there is an intermittent excessive battery draw. TEST the system for normal operation. NO : CHECK for any high resistance or corrosion in the positive battery output (B+) circuit SDC02 (RD) and/or connections. REPAIR as necessary. TEST the system for normal operation.

With the engine running, the charging system warning indicator is off. The sense A circuit SDC02 (RD) to the generator field coil measures 13-15 volts. The S (stator) circuit (internal to the generator on all 4.6L vehicles, but an external circuit VDC42 [GN] on 4.0L vehicles) 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 controller area network (CAN) communication link to the instrument cluster (IC) to turn off the charging system warning indicator. The I (ignition) circuit CDC09 (YE) is used to turn on the voltage regulator. This circuit measures 6-8 volts (C102a [4.0L], C1104a [4.6L] connected) with the key in the ON position and the engine not running. Once the engine is started, the I circuit measures 8-10 volts (C102a [4.0L], C1104a [4.6L] connected). The positive battery output (B+) circuit SDC02 (RD) is the generator output supplied to the battery and electrical system.

This pinpoint test in intended to diagnose the following

1. Generator
2. PCM
3. Circuitry

Scheme 6

Scheme 7

Scheme 8

Scheme 9

1. B1 CHECK THE DTCs IN THE PCM Key in OFF position. Connect the diagnostic tool. Key in ON position. Enter the following diagnostic mode on the diagnostic tool: Retrieve PCM DTCs Use the recorded PCM DTCs from the continuous and on-demand self tests. Are any PCM DTCs recorded (other than DTC P0620)? YES : REFER to the «Introduction - Gasoline Engines»(ref-268480) . If referred here by the PC/ED, go to B2 . NO : Go to B2 .
2. B2 CHECK GENERATOR CIRCUIT SDC02 (RD) FOR VOLTAGE Key in OFF position. Measure the voltage between generator C102b (4.0L), C1104b (4.6L), circuit SDC02 (RD) component side and ground. Is the voltage equal to battery voltage? YES : Go to B3 . NO : REPAIR the circuit. TEST the system for normal operation.
3. B3 CHECK GENERATOR A CIRCUIT SDC02 (RD) Disconnect: Generator C102a (4.0L), C1104a (4.6L) Measure the voltage between generator C102a-3 (4.0L), C1104a-3 (4.6L), circuit SDC02 (RD), harness side and ground. Is the voltage equal to battery voltage? YES : Go to B4 . NO : REPAIR the circuit. TEST the system for normal operation.
4. B4 CHECK CIRCUIT CDC09 (YE) FOR VOLTAGE Key in START position. With the engine running, measure the voltage between generator C102a-1 (4.0L), C1104a-1 (4.6L), circuit CDC09 (YE), harness side and ground. Is the voltage greater than 10 volts? YES : Go to B6 . NO : Go to B5 .
5. B5 CHECK CIRCUIT CDC09 (YE) FOR AN OPEN OR A SHORT TO GROUND Key in OFF position. Disconnect: PCM C175b Measure the resistance between PCM C175b-22, circuit CDC09 (YE), harness side and generator C102a-1 (4.0L), C1104a-1 (4.6L), circuit CDC09 (YE), harness side; and between PCM C175b-22, circuit CDC09 (YE), harness side and ground. Is the resistance less than 5 ohms between the PCM and the generator, and greater than 10,000 ohms between the PCM and ground? YES : Go to B8 . NO : REPAIR the circuit. TEST the system for normal operation.
6. B6 CHECK FOR A VOLTAGE DROP IN CIRCUIT SDC02 (RD) Key in OFF position. Connect: Generator C102a (4.0L), C1104a (4.6L) Key in START position. With the engine running: turn the headlamps on, the heated rear window on (if equipped) and the climate control blower motor to the HIGH position. With the engine running at approximately 2,000 rpm, measure the voltage drop between generator C102b (4.0L), C1104b (4.6L), circuit SDC02 (RD) component side and the positive battery terminal. Is the voltage drop less than 0.5 volt? YES : For the 4.0L engine, go to B7 . For the 4.6L engine, INSTALL a new generator. REFER to «GENERATOR AND REGULATOR»(ref-270906) . TEST the system for normal operation. NO : REPAIR the circuit. TEST the system for normal operation.
7. B7 CHECK THE INTEGRITY OF CIRCUIT VDC42 (GN) Key in OFF position. Inspect circuit VDC42 (GN) for a loose connection/corrosion/damage/loose pin fit or crimp or high resistance. Is the circuit VDC42 (GN) in good condition? YES : Go to B8 . NO : REPAIR the circuit. TEST the system for normal operation.
8. B8 CHECK FOR CORRECT PCM OPERATION Disconnect all the PCM connectors. Check for: corrosion. pushed-out pins. Connect all the PCM connectors and make sure they seat correctly. Operate the system and verify the concern is still present. Is the concern still present? YES : INSTALL a new PCM. REFER to «ELECTRONIC ENGINE CONTROLS»(ref-270955) . TEST the system for normal operation. NO : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. TEST the system for normal operation.

The generator output is determined by the voltage of the A circuit SDC02 (RD). The A circuit voltage is compared to a set voltage internal to the regulator and the regulator controls the generator field current to maintain the correct generator output. The set voltage varies with temperature and is typically higher in cold temperatures and lower in warm temperatures.

This pinpoint test is intended to diagnose the following

1. Circuit SDC02 (RD) high resistance
2. Ground connections
3. Generator
4. PCM

Scheme 10

1. C1 CHECK FOR A VOLTAGE DROP IN CIRCUIT SDC02 (RD) Key in START position. With the engine running: turn the headlamps on, the heated rear window on (if equipped) and the climate control blower motor to the HIGH position. Measure the voltage drop between generator C102a-3 (4.0L), C1104a-3 (4.6L), circuit SDC02 (RD), harness side and the positive battery terminal. Is the voltage drop less than 0.5 volt? YES : Go to C2 . NO : REPAIR the circuit. TEST the system for normal operation.
2. C2 CHECK THE GENERATOR AND THE BATTERY GROUND CONNECTIONS Key in OFF position. Check the ground connections between the generator and the engine, and between the battery and the engine. Are all ground connections clean and tight? YES : INSTALL a new generator. REFER to «GENERATOR AND REGULATOR»(ref-270906) . TEST the system for normal operation. NO : REPAIR the ground connections as necessary. TEST the system for normal operation.

With the engine running, the charging system warning indicator is off. The sense A circuit SDC02 (RD) to the generator field coil measures 13-15 volts. The S (stator) circuit (internal to the generator on all 4.6L vehicles, but an external circuit VDC42 [GN] on 4.0L vehicles) 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 voltage regulator to provide a signal to the PCM, which in turn provides a signal over the controller area network (CAN) communication link to the instrument cluster (IC) to turn off the charging system warning indicator. The I (ignition) circuit CDC09 (YE) is used to turn on the voltage regulator. This circuit measures 6-8 volts (C102a [4.0L], C1104a [4.6L] connected) with the key in the ON position and the engine not running. Once the engine is started, the I circuit measures 8-10 volts (C102a [4.0L], C1104a [4.6L] connected). The positive battery output (B+) circuit SDC02 (RD) is the generator output supplied to the battery and electrical system.

This pinpoint test is intended to diagnose the following

1. IC
2. Generator
3. PCM
4. Circuitry

Scheme 11

1. D1 CHECK THE I CIRCUIT CDC09 (YE) FOR VOLTAGE Key in OFF position. Disconnect: Generator C102a (4.0L), C1104a (4.6L) Key in START position. With the engine running, measure the voltage between generator C102a-1 (4.0L), C1104a-1 (4.6L), circuit CDC09 (YE), harness side and ground. Is the voltage greater than 10 volts? YES : Go to D3 . NO : Go to D2 .
2. D2 CHECK THE I CIRCUIT CDC09 (YE) FOR AN OPEN OR A SHORT TO GROUND Key in OFF position. Disconnect: PCM C175b Measure the resistance between PCM C175b-22, circuit CDC09 (YE), harness side and generator C102a-1 (4.0L), C1104a-1 (4.6L), circuit CDC09 (YE), harness side; and between PCM C175b-22, circuit CDC09 (YE), harness side and ground. Is the resistance less than 5 ohms between the PCM and the generator, and greater than 10,000 ohms between the PCM and ground? YES : Go to D5 . NO : REPAIR the circuit. TEST the system for normal operation.
3. D3 CHECK THE INTEGRITY OF THE GENERATOR Key in OFF position. Connect: Generator C102a (4.0L), C1104a (4.6L) Key in START position. With the engine running, measure the voltage between generator C102a-1 (4.0L), C1104a-1 (4.6L), circuit CDC09 (YE), harness side (back-probed) and ground. Is the voltage 8-10 volts? YES : For the 4.0L engine, go to D4 . For the 4.6L engine, INSTALL a new generator. REFER to «GENERATOR AND REGULATOR»(ref-270906) . TEST the system for normal operation. NO : REFER to «INSTRUMENT CLUSTER»(ref-270940) for the diagnosis of the IC.
4. D4 CHECK THE INTEGRITY OF STATOR CIRCUIT VDC42 (GN) Key in OFF position. Inspect the circuit VDC42 (GN) for a loose connection/corrosion/damage/loose pin fit or crimp or high resistance. Is the circuit VDC42 (GN) in good condition? YES : Go to D5 . NO : REPAIR the circuit. TEST the system for normal operation.
5. D5 CHECK FOR CORRECT PCM OPERATION Disconnect all the PCM connectors. Check for: corrosion. pushed-out pins. Connect all the PCM connectors and make sure they seat correctly. Operate the system and verify the concern is still present. Is the concern still present? YES : INSTALL a new PCM. REFER to «ELECTRONIC ENGINE CONTROLS»(ref-270955) . TEST the system for normal operation. NO : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. TEST the system for normal operation.

Under normal operation, the I (ignition) circuit CDC09 (YE) measures 6-8 volts (C102a [4.0L], C1104a [4.6L] connected) with the key in the ON position and the engine not running. This causes the charging system warning indicator to turn on. This circuit is also used to turn the charging system warning indicator on if there is a fault in the charging system.

This pinpoint test is intended to diagnose the following

1. Generator
2. Instrument cluster (IC)
3. Circuit CDC09 (YE) open

Scheme 12

1. E1 CHECK THE CHARGING SYSTEM WARNING INDICATOR Key in OFF position. Disconnect: Generator C102a (4.0L), C1104a (4.6L) With the engine off, connect a fused (15A) jumper wire between generator C102a-1 (4.0L), C1104a-1 (4.6L), circuit CDC09 (YE), harness side and ground. Key in ON position. Is the charging system warning indicator illuminated? YES : INSTALL a new generator. REFER to «GENERATOR AND REGULATOR»(ref-270906) . TEST the system for normal operation. NO : Go to E2 .
2. E2 CHECK CIRCUIT CDC09 (YE) FOR AN OPEN Key in OFF position. Disconnect: PCM C175b Measure the resistance between PCM C175b-22, circuit CDC09 (YE), harness side and generator C102a-1 (4.0L), C1104a-1 (4.6L), circuit CDC09 (YE), harness side. Is the resistance less than 5 ohms? YES : REFER to «INSTRUMENT CLUSTER»(ref-270940) for the diagnosis of the IC. NO : REPAIR the circuit. TEST the system for normal operation.

With the engine running, the charging system warning indicator is off. The A (battery sense) circuit SDC02 (RD) to the generator field coil measures 13-15 volts. The S (stator) circuit (internal to the generator on all 4.6L vehicles but an external circuit VDC42 [GN] on 4.0L vehicles) 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 controller area network (CAN) communication link to the instrument cluster (IC) to turn off the charging system warning indicator. The I (ignition) circuit CDC09 (YE) is used to turn on the voltage regulator. This circuit measures 6-8 volts (C102a [4.0L], C1104a [4.6L] connected) with the key in the ON position and the engine not running. Once the engine is started, the I circuit measures 8-10 volts (C102a [4.0L], C1104a [4.6L] connected). The positive battery output (B+) circuit SDC02 (RD) is the generator output supplied to the battery and electrical system.

This pinpoint test is intended to diagnose the following

1. Fusible link
2. Generator connections
3. Generator

Scheme 13

1. F1 CHECK FOR LOOSE CONNECTIONS Key in OFF position. Check all generator, battery, battery junction box (BJB) and smart junction box (SJB) connections for looseness, corrosion, loose or bent terminals, loose eyelets or damaged fusible links. Are all the connections clean and tight? YES : Go to F2 . NO : REPAIR as necessary. TEST the system for normal operation.
2. F2 CHECK THE FUSIBLE LINK CONNECTIONS Key in START position. With the engine running, check the fusible links SDF01 8 gauge (GY), SDF03 20 gauge (BN) in A circuit SDC02 (RD) for looseness by wiggling the fuse links and noting the charging system warning indicator operation. Does the charging system warning indicator flicker? YES : REPAIR the loose fusible link(s) as necessary. TEST the system for normal operation. NO : Go to F3 .
3. F3 CHECK CIRCUIT SDC02 (RD) CONNECTIONS Key in OFF position. Connect a fused (15A) jumper wire between generator C102a-3 (4.0L), C1104a-3 (4.6L), circuit SDC02 (RD), harness side and the positive battery terminal. Key in START position. With the engine running, note the charging system warning indicator operation. Does the charging system warning indicator flicker? YES : INSTALL a new generator. REFER to «GENERATOR AND REGULATOR»(ref-270906) . TEST the system for normal operation. NO : REPAIR the loose connection(s). TEST the system for normal operation.

The generator is belt-driven by the engine accessory drive system.

This pinpoint test is intended to diagnose the following

1. Loose bolts/brackets
2. Drive belt
3. Generator/pulley

The generator radio suppression equipment reduces interference transmitted through the speakers by the vehicle electrical system.

This pinpoint test is intended to diagnose the following

1. Generator
2. In-vehicle entertainment system