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Pinpoint Test D: DTC P0625 or P0626




Pinpoint Test





Pinpoint Test D: DTC P0625 or P0626

Refer to Wiring Diagrams Cell 12, Charging System for schematic and connector information. [1][2]Diagrams By Number

Normal Operation

The PCM monitors the generator output via the 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 rises above approximately 2,000 rpm, the generator will default to a steady voltage of approximately 13.5 volts and the PCM will send a request to the Instrument Cluster (IC) to illuminate the charging system warning indicator. A GENMON duty cycle of 3% or less indicates a short to ground fault is present and will result 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 will result in DTC P0626 setting in the PCM.

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

- DTC P0626 (Generator Field Terminal Circuit High)- If the GENMON circuit is open or shorted to power, the PCM will set this DTC. 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.

D1 CHECK THE BATTERY CONDITION

- 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. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.

D2 CHECK THE GENERATOR B+ CONNECTION

- Ignition OFF.

- Inspect generator C102B, circuit SDC14 (RD), harness side. Connection should be tight.

- Inspect generator radial adapter connection on rear of generator. Connection should be tight.

- Measure the voltage between generator C102B, circuit SDC14 (RD) and ground.





Are the generator C102B and radial arm adapter connections tight and does the generator B+ measure battery voltage?

Yes
GO to D3.

No
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. [1][2]Diagrams By Number

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.

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 C102A-3, circuit SBB17 (RD), harness side.





Does the test lamp illuminate?

Yes
GO to D5.

No
VERIFY Battery Junction Box (BJB) fuse 17 (10A) is OK. If OK, REPAIR circuit SBB17 (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. [1][2]Diagrams By Number

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

- Ignition OFF.

- Disconnect: PCM C175B (2.5L or 3.0L).

- Disconnect: PCM C175E (3.5L).

- Inspect the following harness connectors for damaged or pushed-out pins:
- PCM C175B-14, circuit CDC15 (VT) (2.5L or 3.0L)

- PCM C175E-26, circuit CDC15 (VT) (3.5L)

- 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.

D6 CHECK THE GENERATOR B+ RESISTANCE

- Ignition OFF.

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

Disconnect the battery.

- 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 - 2.5L , Generator - 3.0L or Generator - 3.5L . CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.

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.

Pin Expected Resistance 1 Greater than 10K ohms 2 Greater than 10K ohms 3 Greater than 10K ohms

Are the resistance values as indicated?

Yes
GO to D8.

No
INSTALL a new generator. REFER to Generator - 2.5L , Generator - 3.0L or Generator - 3.5L . CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.

D8 CHECK CIRCUIT CDC15 (VT) FOR DAMAGE OR AN OPEN

- Ignition OFF.

- Disconnect: PCM C175B (2.5L or 3.0L).

- Disconnect: PCM C175E (3.5L).

- Inspect the following harness connectors for damaged or pushed-out pins:
- PCM C175B-14 (2.5L or 3.0L), circuit CDC15 (VT)

- PCM C175E-26 (3.5L), circuit CDC15 (VT)

- Generator C102A-1, circuit CDC15 (VT)


- For 2.5L or 3.0L engines, measure the resistance between PCM C175B-14, circuit CDC15 (VT), harness side and generator C102A-1, circuit CDC15 (VT), harness side.

- For 3.5L engines, measure the resistance between PCM C175E-26, 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.

D9 CHECK CIRCUIT CDC15 (VT) FOR A SHORT TO POWER

- Connect the battery.

- 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.

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

- Ignition OFF.

- Connect: PCM C175B (2.5L or 3.0L).

- Connect: PCM C175E (3.5L).

- 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 - 2.5L , Generator - 3.0L or Generator - 3.5L . CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.

No
GO to D11.

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/bent pins.


- 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. 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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