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Pinpoint Test D: DTC P0625 or P0626




Pinpoint Test

Pinpoint Test D: DTC P0625 or P0626

Refer to Wiring Diagram Set 12, Charging System for schematic and connector information. Diagrams By Number

Normal Operation

The PCM monitors the generator output via the generator monitor (GENMON) circuit (generator field terminal circuit). If the PCM cannot read the GENMON circuit due to an open or short to ground, when the engine speed is greater than approximately 2,000 rpm, the generator defaults to a steady voltage of approximately 13.5 volts and the PCM sends a request to the Instrument Panel Cluster (IPC) to illuminate the charging system warning indicator. A GENMON duty cycle of 3% or less indicates a short to ground fault is present and results in DTC P0625 setting in the PCM. A GENMON duty cycle of 98% or more indicates an open or short to voltage fault is present and results in DTC P0626 setting in the PCM.

- DTC P0625 (Generator Field Terminal Circuit Low) - The PCM sets this DTC if the GENMON circuit is shorted to ground, the "A" sense circuit is open or the B+ circuit is open. This DTC also sets by a faulted PCM or generator.
- DTC P0626 (Generator Field Terminal Circuit High) - The PCM sets this DTC if the GENMON circuit is open or shorted to power. This DTC can also be set by a faulted PCM or generator.

This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Radial arm adapter
- Engine, generator and battery grounds
- Battery
- Generator
- PCM

PINPOINT TEST D: DTC P0625 OR P0626

NOTE: Make sure battery voltage is greater than 12.2 volts prior to and during this pinpoint test.

NOTE: Do not have a battery charger attached during vehicle testing.

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D1 CHECK THE BATTERY CONDITION

- Refer to Battery, Mounting and Cables Pinpoint Tests and carry out Pinpoint Test A: Battery Condition Test to determine if the battery can hold a charge and is OK for use. Pinpoint Tests
- Does the battery pass the condition test?

Yes
GO to D2.

No
INSTALL a new battery. REFER to Battery, Mounting and Cables Battery and Battery Tray - Exploded View. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.

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D2 CHECK THE GENERATOR B+ CONNECTION

- Ignition OFF.
- Inspect generator C102B, circuit SDC14 (RD), harness side. Connection should be tight.
- Inspect generator radial adaptor connection on rear of generator. Connection should be tight.
- Measure the voltage between generator C102B, circuit SDC14 (RD) and ground.




- Are the generator C102B connections tight and does the generator B+ measure battery voltage?

Yes
GO to D3.

No
For 3.5L, 3.7L and 5.0L engines, TIGHTEN or INSTALL a new C102B (B+ nut) and/or radial arm adapter as needed. REFER to Specifications. VERIFY high current BJB 250A fuse is OK. If OK, REPAIR circuit SDC14 (RD). If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. Diagrams By Number

For 6.2L engines, TIGHTEN or INSTALL a new C102B (B+ nut) and/or radial arm adapter as needed. REFER to Specifications. VERIFY the fusible link is OK. If the fusible link is OK, REPAIR circuit SDC14 (RD). If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. Diagrams By Number

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D3 CHECK THE VOLTAGE DROP IN THE B+ CIRCUIT

- Start the engine.
- With the engine running at idle, headlamps on and blower on high, measure the voltage drop between generator B+ C102B, circuit SDC14 (RD) and the positive battery terminal.




- Carry out a wiggle test of the generator wiring and connections while measuring voltage drop.
- Is the voltage drop less than 0.5 volt?

Yes
For DTC P0625, GO to D4.

For DTC P0626, GO to D6.

No
INSPECT circuit SDC14 (RD), radial arm adapter and the positive battery cable for loose connections, physical damage or wire corrosion. REPAIR as necessary. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.

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D4 "A" SENSE CIRCUIT LOAD TEST

NOTICE: The following step uses a test light to simulate normal circuit loads. Use only the test light recommended in the Special Tools table at the beginning. To avoid connector terminal damage, use the Flex Probe Kit for the test light probe connection to the vehicle. Do not use the test light probe directly on any connector.

NOTE: This step puts a load on the "A" sense circuit. If there are corroded or loose connections, loading the circuit may help show the fault. A 250-350 mA incandescent 12-volt test lamp is required for this step. This circuit will not be loaded properly using an LED-style test lamp.

- Ignition OFF.
- Disconnect: Generator C102A .
- Ignition ON.
- Using a 12-volt test lamp connected to ground, check for voltage at:
- For 3.5L, 3.7L and 5.0L engines, generator C102A-3, circuit SBB45 (GY/RD), harness side.
- For 6.2L engines, generator C102A-3, circuit SDC14 (RD), harness side.




- Does the test lamp illuminate?

Yes
GO to D5.

No
For 3.5L, 3.7L and 5.0L engines, VERIFY high current BJB 250A fuse is OK. If OK, REPAIR circuit SDC14 (RD). If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. Diagrams By Number

For 6.2L engines, VERIFY fusible links are OK. If OK, REPAIR circuit SDC14 (RD). If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. Diagrams By Number

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D5 CHECK CIRCUIT CDC15 (VT) FOR DAMAGE OR A SHORT TO GROUND

- Ignition OFF.
- Disconnect: PCM C1551B (3.5L).
- Disconnect: PCM C175B (3.7L).
- Disconnect: PCM C1381B (5.0L and 6.2L).
- Inspect the following harness connectors for damaged or pushed-out pins:
- PCM C1551B-26, circuit CDC15 (VT) (3.5L)
- PCM C175B-14, circuit CDC15 (VT) (3.7L)
- PCM C1381B-14, circuit CDC15 (VT) (5.0L and 6.2L)
- Generator C102A-1, circuit CDC15 (VT)
- Measure the resistance between generator C102A-1, circuit CDC15 (VT), harness side and ground.




- Are the connectors and pins free of damage and is the resistance greater than 10,000 ohms?

Yes
GO to D10.

No
REPAIR the connector(s) and/or circuit CDC15 (VT). CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.

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D6 CHECK THE GENERATOR B+ RESISTANCE

- Ignition OFF.

- NOTE: Failure to disconnect the battery will result in false resistance readings.

- Disconnect the battery. Refer to Battery, Mounting and Cables Battery Disconnect.
- Disconnect: Generator C102B.
- Measure the resistance between generator C102B, component side and the generator housing.




- Is the resistance greater than 25K ohms?

Yes
GO to D7.

No
INSTALL a new generator. REFER to Generator - 3.5L GTDI Service and Repair, Generator - 3.7L Service and Repair, Generator - 5.0L Service and Repair or Generator - 6.2L Service and Repair. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.

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D7 CHECK THE RESISTANCE OF THE VOLTAGE REGULATOR INTERNAL CIRCUITS TO GROUND

- Disconnect: Generator C102A.
- Measure the resistance between generator C102A, component side and ground. Refer to the following table.





- Are the resistance values as indicated?

Yes
GO to D8.

No
INSTALL a new generator. REFER to Generator - 3.5L GTDI Service and Repair, Generator - 3.7L Service and Repair, Generator - 5.0L Service and Repair or Generator - 6.2L Service and Repair. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.

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D8 CHECK THE GENMON CIRCUIT FOR DAMAGE OR AN OPEN

- Disconnect: PCM C1551B (3.5L).
- Disconnect: PCM C175B (3.7L).
- Disconnect: PCM C1381B (5.0L and 6.2L).
- Inspect the following harness connectors for damaged or pushed-out pins:
- PCM C1551B-26, circuit CDC15 (VT) (3.5L)
- PCM C175B-14, circuit CDC15 (VT) (3.7L)
- PCM C1381B-14, circuit CDC15 (VT) (5.0L and 6.2L)
- Generator C102A-1, circuit CDC15 (VT)
- For 3.5L equipped vehicles, measure the resistance between PCM C1551B-26, circuit CDC15 (VT), harness side and generator C102A-1, circuit CDC15 (VT), harness side.




- For 3.7L equipped vehicles, measure the resistance between PCM C175B-14, circuit CDC15 (VT), harness side and generator C102A-1, circuit CDC15 (VT), harness side.




- For 5.0L an 6.2L equipped vehicles, measure the resistance between PCM C1381B-14, circuit CDC15 (VT), harness side and generator C102A-1, circuit CDC15 (VT), harness side.




- Are the connectors and pins free of damage and is the resistance less than 5 ohms?

Yes
GO to D9.

No
REPAIR the connector(s) and/or circuit CDC15 (VT). CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.

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D9 CHECK THE GENMON CIRCUIT FOR A SHORT TO POWER

- Connect the battery. Refer to Battery, Mounting and Cables Battery Disconnect.
- Ignition ON.
- Measure the voltage between generator C102A-1, circuit CDC15 (VT), harness side and ground.




- Is there any voltage present?

Yes
REPAIR the connector(s) and/or circuit CDC15 (VT). CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.

No
GO to D10.

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D10 COMPARE THE PCM PIDs GENERATOR MONITOR (GENMON) AND GENERATOR COMMAND (GENCMD)

- Ignition OFF.
- Disconnect: PCM C1551B (3.5L).
- Disconnect: PCM C175B (3.7L).
- Disconnect: PCM C1381B (5.0L and 6.2L).
- Connect a fused jumper wire between generator C102A-1, circuit CDC15 (VT), harness side and generator C102A-2, circuit CDC10 (BU/OG), harness side.




- Start the engine.
- Using the active command, set the GENVDSD PID to 14.0 volts.
- Monitor the GENMON and GENCMD PIDs while carrying out a wiggle test on the generator wiring harness.
- Does the GENMON PID read within 2% of the GENCMD PID?

Yes
INSTALL a new generator. REFER to Generator - 3.5L GTDI Service and Repair, Generator - 3.7L Service and Repair, Generator - 5.0L Service and Repair or Generator - 6.2L Service and Repair. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.

No
GO to D11.

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D11 CHECK FOR CORRECT PCM OPERATION

- Ignition OFF.
- Disconnect: Fused Jumper Wire.
- Check the PCM harness, generator harness, PCM component side and generator component side connectors for:
- corrosion
- pushed-out pins and terminals
- damaged pins and terminals
- Connect the PCM and/or generator connectors. Make sure the connectors seat correctly.
- Operate the system and determine if the concern is still present.
- Is the concern still present?

Yes
INSTALL a new PCM. REFER to Electronic Engine Controls Service and Repair. CLEAR the DTCs. REPEAT the self-test. 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. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.

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