Pinpoint Test H: U012F And U044D
- Refer to Wiring Diagrams Charging System
for schematic and connector information.
Normal Operation and Fault Conditions
The charging system supplies voltage to the battery and the vehicle electrical system through the battery B+ cable. The PCM monitors the generator output through a LIN communication circuit. The PCM uses this LIN circuit to communicate the desired voltage setpoint to the generator internal voltage regulator. The generator also uses this to communicate the generator load and error conditions to the PCM.
DTC Fault Trigger Conditions
DTC Description Fault Trigger Condition PCM U012F:00 Lost Communication With Generator "B" Control Module: No Sub Type Information Sets if the PCM does not detect communication through the LIN circuit. This can be a result of an open or short in the LIN circuit. This DTC also sets if the generator B+ circuit is open. PCM U044D:00 Invalid Data Received From Generator "B" Control Module: No Sub Type Information Sets when the PCM receives invalid data from the generator. Possible Sources
- DC/AC inverter
- Generator
- PCM
- Wiring, terminals or connectors
Visual Inspection and Pre-checks
- Inspect high current BJB for loose, damaged or corroded connections.
- Inspect the BJB fuse 201 (300A).
- Inspect the BJB fuse 25 (10A).
- Inspect the FEAD belt.
- Inspect the battery monitoring sensor.
- 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.
- H1 COMPARE THE GENERATOR B+ CIRCUIT TO BATTERY VOLTAGE
- Measure:
Positive Lead Measurement / Action Negative Lead C1251B-1 Ground
Is the voltage within 0.5 volt of the recorded battery voltage?
Yes GO to H2 No TIGHTEN or INSTALL a new generator B+ nut as needed. REFER to: Generator - 3.0L Power Stroke Diesel . VERIFY high current BJB fuse 201 (300A) is OK. If OK, REPAIR the circuit. If not OK, REFER to the OEM ELECTRICAL WIRING DIAGRAM INTRODUCTION to identify the possible causes of the circuit short. - Measure:
- H2 CHECK THE GENERATOR LIN (LOCAL INTERCONNECT NETWORK) CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect secondary generator C1251B.
- Disconnect DC/ AC inverter C3501C.
- Ignition ON.
- Measure:
Positive Lead Measurement / Action Negative Lead C1251A-2 Ground
Is any voltage present?
Yes REPAIR the circuit. No GO to H3 - H3 CHECK THE GENERATOR LIN (LOCAL INTERCONNECT NETWORK) CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Measure and record:
Positive Lead Measurement / Action Negative Lead C1251A-2 Ground
Is the resistance greater than 10, 000 ohms?
Yes GO to H4 No REPAIR the circuit. - H4 CHECK THE GENERATOR LIN (LOCAL INTERCONNECT NETWORK) CIRCUIT FOR AN OPEN
- Ignition OFF.
Is the resistance less than 3 ohms?
Yes INSTALL a new generator. REFER to: Generator - 3.0L Power Stroke Diesel . REPEAT the PCM self-test. If DTC U012D is retrieved again, GO to H5 No REPAIR the affected circuit. - H5 CHECK FOR CORRECT PCM (POWERTRAIN CONTROL MODULE) OPERATION
- Ignition OFF.
- Disconnect and inspect all PCM connectors.
- Repair:
- corrosion (install new connector or terminals - clean module pins)
- damaged or bent pins - install new terminals/pins
- pushed-out pins - install new pins as necessary
- Reconnect the PCM connectors. Make sure they seat and latch correctly.
- Operate the system and determine if the concern is still present.
Is the concern still present?
Yes CHECK OASIS for any applicable Technical Service Bulletins (TSBs). If a TSB exists for this concern, DISCONTINUE this test and FOLLOW the TSB instructions. If no Technical Service Bulletins (TSBs) address this concern, Refer to PCM GUIDED ROUTINE TESTING
Internet Explorer version 11 or greater is required to perform this Pinpoint Test.No The system is operating correctly at this time. The concern may have been caused by module connections. ADDRESS the root cause of any connector or pin issues.