Pinpoint Test J: DTCs P163C and P163D
Pinpoint Test
Pinpoint Tests
Pinpoint Test J: DTCs P163C and P163D
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 GENMON2 circuit (generator field terminal circuit). If the PCM cannot read the GENMON2 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 lamp.
- DTC P163C (Generator Field Terminal Circuit Low) - If the GENMON circuit is shorted to ground or the A sense is open, the PCM will set this DTC. This DTC can also be set by a faulty PCM or generator.
- DTC P163D (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 poor engine ground or faulty PCM or generator.
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Engine, generator and battery grounds
- Battery
- Generator
- PCM
PINPOINT TEST J: DTCs P163C AND P163D
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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J1 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. Pinpoint Tests
- Does the battery pass the condition test?
Yes
GO to J2.
No
INSTALL a new battery. REFER to Battery. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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J2 CHECK THE GENERATOR B+ CONNECTION
- Ignition OFF.
- Inspect generator C1251C, circuit SDC16 (RD), harness side. Connection should be tight.
- Measure the voltage between generator C1251C, circuit SDC16 (RD) and ground.
- Is the generator C1251C connection tight and does the generator B+ measure battery voltage?
Yes
GO to J3.
No
REPAIR the generator B+ connection or circuit. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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J3 CHECK THE A SENSE VOLTAGE
- Disconnect: Generator C1251A.
- Ignition ON.
- Measure battery voltage and record.
- Measure the voltage between generator C1251A-3, circuit SDC16 (RD), harness side and ground.
- Is the voltage equal to battery voltage?
Yes
GO to J4.
No
VERIFY fusible links are OK. If OK, REPAIR circuit SDC16 (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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J4 MONITOR THE PCM PID GENERATOR MONITOR (GENMON2) WITH IGNITION ON/ENGINE OFF
- Connect: Generator C1251A.
- NOTE: Many of the PCM PIDs selected will be monitored later in this pinpoint test.
- Select and monitor the following PCM PIDs:
- Generator Monitor (GENMON2).
- Generator Command (GENCMD2).
- Generator Voltage Desired (GENVDSD2).
- Engine Revolutions Per Minute (RPM).
- Module Supply Voltage (VPWR).
- Monitor the GENMON2 PID.
- Does the GENMON2 PID read 0%?
Yes
GO to J5.
No
GO to J10.
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J5 MONITOR THE PCM PIDs GENERATOR MONITOR (GENMON) AND GENERATOR VOLTAGE DESIRED (GENVDSD) WITH ENGINE RUNNING AND NO LOADS
- Start the engine and turn all electrical accessories (lights, blower motor, etc.) off.
- With the engine at idle, wait at least 15 seconds for the GENVDSD2 PID to increase to greater than 13 volts.
- Monitor PID GENMON2 at idle.
- NOTE: On some vehicles equipped with a manual transaxle/transmission, the parking brake must be applied and the clutch pedal depressed in order to use the output state control RPM.
- Using output state control PID RPM, increase the engine rpm to 3,000 rpm.
- Monitor PID GENMON2 at 3,000 rpm.
- Does the GENMON2 PID read between 3% and 98% at engine idle speed and at 3,000 rpm?
Yes
GO to J6.
No
GO to J11.
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J6 MONITOR THE PCM PIDs GENERATOR MONITOR 2 (GENMON2), GENERATOR VOLTAGE DESIRED 2 (GENVDSD2) WITH THE ENGINE AT IDLE LOADS ON
- Decrease the engine speed to 500 rpm using active command PID RPM and monitor PIDs.
- NOTE: On vehicles with low electrical loads, it is necessary to make sure that all of the vehicles electrical loads are turned on to determine the maximum GENMON2 PID value. The GENMON2 PID value may not reach between the desired 95%-98% on a low load vehicle with minimal electrical accessories. As long as the GENMON2 PID increases significantly with all of the electrical loads on, answer YES to the question below.
- Determine the maximum GENMON2 PID value by lowering engine idle rpm to 500 rpm or less using output state control PID RPM and turn on all electrical accessories until the module supply voltage (VPWR) PID is less than the GENVDSD2 PID by at least 0.7 volt. Under this condition the GENMON2 PID should read between 95% and 98%.
- Does the GENMON2 PID read between 95% and 98%?
Yes
GO to J7.
No
GO to J11.
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J7 MONITOR THE PCM PIDs GENERATOR MONITOR 2 (GENMON2), MODULE SUPPLY VOLTAGE (VPWR) AND GENERATOR VOLTAGE DESIRED 2 (GENVDSD2) WITH THE ENGINE AT 3,000 RPM
- Increase the engine speed to 3,000 rpm using active command PID RPM and monitor PIDs.
- NOTE: If GENMON2 PID does not remain below 85%, make sure that the battery is at an acceptable state of charge and that all electrical accessories are off.
- Monitor PIDs VPWR, GENVDSD2 and GENMON2.
- Does the VPWR PID remain within ±0.5 volt of the GENVDSD2 PID when the GENMON2 PID is less than 85%?
Yes
GO to J8.
No
GO to J11.
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J8 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.
- Disconnect: Generator C1251C.
- Measure the resistance between generator C1251C, component side and the generator housing.
- Is the resistance greater than 25K ohms?
Yes
GO to J9.
No
INSTALL a new generator. REFER to Generator - 6.4L Diesel, Dual Generator . CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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J9 CHECK THE RESISTANCE OF THE VOLTAGE REGULATOR INTERNAL CIRCUITS TO GROUND
- Disconnect: Generator C1251A.
- Measure the resistance between generator C1251A, component side and ground. Refer to the following table.
- Are the resistance values as indicated?
Yes
The fault is not present at this time. This may indicate an intermittent fault. CARRY OUT a wiggle test on the charging system circuits to try and RECREATE the concern. CHECK generator connections for corrosion, loose connections and/or bent terminals. REPAIR as necessary. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
No
INSTALL a new generator. REFER to Generator - 6.4L Diesel, Dual Generator . CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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J10 CHECK THE PCM PID GENERATOR MONITOR 2 (GENMON2) INPUT TO THE PCM
- Ignition OFF.
- Disconnect: Generator C1251A.
- Connect a fused jumper wire between generator C1251A-1, circuit CDC47 (WH), harness side and ground.
- Ignition ON.
- Monitor the GENMON2 PID while performing a wiggle test on the generator wiring harness.
- Does the GENMON2 PID read 0%?
Yes
GO to J14.
No
GO to J15.
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J11 A SENSE CIRCUIT LOAD TEST
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 glass bulb-style test lamp is required for this step. This circuit will not be loaded properly using an LED-style test lamp.
- Ignition OFF.
- Disconnect: Generator C1251A (if not previously disconnected).
- Ignition ON.
- Using a 12-volt test lamp connected to ground, check for voltage at C1251A-3, circuit SDC16 (RD), harness side.
- Does the test lamp illuminate?
Yes
GO to J12.
No
VERIFY fusible links are OK. If OK, REPAIR circuit SDC16 (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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J12 B+ CIRCUIT LOAD TEST
NOTE: This step puts a load on the B+ circuit. If there are corroded or loose connections, loading the circuit may help show the fault. A glass bulb-style test lamp is required for this step. This circuit will not be loaded properly using an LED-style test lamp.
- Ignition OFF.
- Disconnect: Generator C1251C.
- Using a 12-volt test lamp connected to ground, check for voltage at C1251C-1, circuit SDC16 (RD), harness side.
- Does the test lamp illuminate?
Yes
GO to J13.
No
REPAIR circuit SDC16 (RD) for high resistance. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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J13 CHECK CIRCUIT CDC48 (YE/GN) FOR DAMAGE OR AN OPEN
- Ignition OFF.
- Disconnect: PCM C1232B.
- Inspect the following harness connectors for damaged or pushed-out pins:
- PCM C1232B-55, circuit CDC48 (YE/GN).
- Generator C1251A-2, circuit CDC48 (YE/GN).
- Measure the resistance between PCM C1232B-55, circuit CDC48 (YE/GN), harness side and generator C1251A-2, circuit CDC48 (YE/GN), harness side.
- Are the connectors and pins free of damage and is the resistance less than 0.5 ohm?
Yes
GO to J14.
No
REPAIR circuit CDC10 (BU/OG). CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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J14 COMPARE THE PCM PIDs GENERATOR MONITOR 2 (GENMON2) AND GENERATOR COMMAND 2 (GENCMD2)
- Connect: Generator C1251C.
- Connect: PCM C1232B.
- Connect a fused jumper wire between generator C1251A-1, circuit CDC47 (WH), harness side and generator C1251A-2, circuit CDC48 (YE/GN), harness side.
- Start the engine.
- Using output state control, set the GENVDSD2 PID to 14.0 volts.
- Monitor the GENMON2 and GENCMD2 PIDs while performing a wiggle test on the generator wiring harness.
- Does the GENMON2 PID read within 2% of the GENCMD2 PID?
Yes
INSTALL a new generator. REFER to Generator - 6.4L Diesel, Dual Generator . CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
No
GO to J16.
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J15 INSPECT GENERATOR CIRCUITS AND CONNECTORS
- Ignition OFF.
- Disconnect: PCM C1232B.
- Inspect the following connector pins for damage and/or corrosion, generator C1251A-1, circuit CDC47 (WH) and PCM C1232B-42.
- Are circuits and connectors OK?
Yes
INSTALL a new PCM. REFER to Computers and Control Systems. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
No
REPAIR the circuit(s) and/or connector(s) as necessary. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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J16 INSPECT PCM CIRCUITS
- Ignition OFF.
- Disconnect: PCM C1232B.
- Inspect the following connector pins for damage and/or corrosion, PCM C1232B-42, circuit CDC47 (WH) and PCM C1232B-55, circuit CDC48 (YE/GN) and the generator.
- Are the connectors OK?
Yes
INSTALL a new PCM. REFER to Computers and Control Systems. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
No
REPAIR the affected circuit(s). CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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