Pinpoint Test D: P2D57

WARNING: This page is about a different car, the 2021 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.

Refer to Wiring Diagrams Charging System for schematic and connector information.

DTC Fault Trigger Conditions

DTC	Description	Fault Trigger Condition
PCM P2D57:00	Generator "B" Control Circuit Range/Performance: No Sub Type Information	This DTC sets when the generator reports an internal regulator failure.
BCM B1513:09	Vehicle Battery "B": Component Failures	A continuous and on-demand DTC that sets in the BCM if the BCM detects higher or Lower than expected battery voltage on the voltage supply input circuit.

Possible Sources

Battery
Fuses or fusible links
Generator
PCM
Wiring, terminals or connectors

Visual Inspection and Pre-checks

Inspect the FEAD system. REFER to 303-05.
Inspect for abnormal ignition-off current drain(s).
Inspect the battery.
Inspect the high current BJB for loose, damaged or corroded connections.
Verify the BJB fuse 201 (300A).

NOTE: Make sure battery voltage is greater than 24 volts prior to and during this pinpoint test.
NOTE: Do not have a battery charger attached during vehicle testing.

D1 PERFORM INSPECTION AND VERIFICATION
- Perform Inspection and Verification procedure In this Service Information.
Was an obvious cause for an observed or reported concern found?

Yes CORRECT the cause as necessary.

No GO to D2

D2 MEASURE THE "B" SENSE VOLTAGE

Ignition OFF.

Disconnect generator C1251A.

Ignition ON.

Measure and record:

Positive Lead	Measurement / Action	Negative Lead
Courtesy of FORD MOTOR COMPANY	Courtesy of FORD MOTOR COMPANY	Courtesy of FORD MOTOR COMPANY

Measure:

Positive Lead	Measurement / Action	Negative Lead
C1251A-1	Courtesy of FORD MOTOR COMPANY	Ground

Is the "B" sense voltage equal to the recorded battery voltage?

Yes

GO to D3

No	VERIFY the BJB fuse 25 (10A) 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.

D3 "B" SENSE CIRCUIT LOAD TEST

WARNING: 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 of this information. 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.

Ignition ON.

Measure:

Positive Lead	Measurement / Action	Negative Lead
Courtesy of FORD MOTOR COMPANY

Connect the load to each circuit and measure:

Positive Lead	Measurement / Action	Negative Lead
C1251A-1	Courtesy of FORD MOTOR COMPANY	Ground

Is the "B" sense voltage within +/-0.5 volt of the recorded battery voltage?

Yes

GO to D4

No	VERIFY the BJB fuse 25 (10A) 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.

D4 CHECK THE GENERATOR CONNECTIONS

Ignition OFF.

Disconnect Generator C1251B.

Disconnect Generator C1251A.

Inspect for :
- 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 generator connectors. Make sure they seat and latch correctly

Measure and record:

Positive Lead	Measurement / Action	Negative Lead
Courtesy of FORD MOTOR COMPANY	Courtesy of FORD MOTOR COMPANY	Courtesy of FORD MOTOR COMPANY

Measure :

Positive Lead	Measurement / Action	Negative Lead
C1251B	Courtesy of FORD MOTOR COMPANY	Ground

Is the voltage within 0.5 volt of the recorded battery voltage?

Yes

GO to D5

TIGHTEN or INSTALL a new generator B+ nut as needed. REFER to: Generator - 2.7L EcoBoost (238kW/324PS) . REFER to: Generator - 3.5L EcoBoost (BM) . VERIFY BJB fuse F201 (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.

D5 CHECK THE VOLTAGE DROP IN THE GENERATOR B+ CIRCUIT

Start the engine.

With the engine running at idle, headlamps on and blower on high, measure:

Positive Lead	Measurement / Action	Negative Lead
C1251A-1	Courtesy of FORD MOTOR COMPANY

Perform a wiggle test of the generator wiring and connections while measuring voltage drop.

Is the voltage drop less than 0.5 volt?

Yes

GO to D6

No	INSPECT and REPAIR any corrosion in the generator B+ circuit or positive battery cable connections.

D6 CHECK THE VOLTAGE DROP IN THE VEHICLE GROUNDS

With the engine still running at idle, headlamps on and heater blower on high, measure:

Positive Lead	Measurement / Action	Negative Lead
Courtesy of FORD MOTOR COMPANY Generator case	Courtesy of FORD MOTOR COMPANY	Courtesy of FORD MOTOR COMPANY

Is the voltage drop less than 0.5 volt?

Yes

GO to D7

No	INSPECT and REPAIR the engine ground, generator ground or the battery ground for corrosion.

D7 MONITOR THE GENERATOR VOLTAGE DESIRED (GENVDSD) PID (PARAMETER IDENTIFICATION) WHILE COMMANDED

Using a diagnostic scan tool, view the DC/ AC invertor GENVDSD PID.

Using a diagnostic scan tool active command, set
Access the PCM and monitor the GENVDSD (V) PIDto 14 volts.

With the engine still running at idle, measure battery and record:

Positive Lead	Measurement / Action	Negative Lead
Courtesy of FORD MOTOR COMPANY	Courtesy of FORD MOTOR COMPANY	Courtesy of FORD MOTOR COMPANY

Is the recorded battery voltage within +/-0.5 volt of the PID?

Yes

GO to D8

GO to D12

D8 COMPARE THE SUPPLY VOLTAGE (VPWR) PID (PARAMETER IDENTIFICATION) TO BATTERY VOLTAGE

With the engine still running at idle, headlamps on and blower on high, measure and record:

Positive Lead	Measurement / Action	Negative Lead
Courtesy of FORD MOTOR COMPANY	Courtesy of FORD MOTOR COMPANY	Courtesy of FORD MOTOR COMPANY

Access the PCM and monitor the VPWR (V) PID

Does the PID accurately display battery voltage within +/-0.5 volt of the recorded battery voltage?

Yes

GO to D9

No	REPAIR high resistance or loose connections in the affected DC/ AC invertor power circuit(s).

D9 CHECK DC (DIRECT CURRENT) / AC (ALTERNATING CURRENT) INVERTER VOLTAGE SUPPLY CIRCUITS

Ignition OFF.

Disconnect DC / AC inverter C3501C.

Ignition ON.

Measure and record:

Positive Lead	Measurement / Action	Negative Lead
C3501C-6	Courtesy of FORD MOTOR COMPANY	Ground

Are the voltages within 0.5 volt of the recorded battery voltage?

Yes

GO to D10

No	REPAIR the affected circuit(s).

D10 CHECK DC (DIRECT CURRENT) / AC (ALTERNATING CURRENT) INVERTER MODULE GROUND FOR HIGH RESISTANCE

NOTE: Measure battery voltage at the battery.

With the engine still running at idle, turn off all accessory loads, measure and record:

Positive Lead	Measurement / Action	Negative Lead
Courtesy of FORD MOTOR COMPANY	Courtesy of FORD MOTOR COMPANY	Courtesy of FORD MOTOR COMPANY

Access the PCM and monitor the VPWR (V) PIDand record.

With the engine still running at idle, turn headlamps ON and blower on HIGH.

Measure and record:

Positive Lead	Measurement / Action	Negative Lead
Courtesy of FORD MOTOR COMPANY	Courtesy of FORD MOTOR COMPANY	Courtesy of FORD MOTOR COMPANY

Using a diagnostic scan tool, view
Access the PCM and monitor the VPWR (V) PIDand record.

Does the PID read within +/-0.5 volt of battery voltage with accessory loads on and off?

Yes

GO to D11

No	REPAIR the affected PCM ground circuit(s).

D11 MONITOR THE SUPPLY VOLTAGE (VPWR) PID (PARAMETER IDENTIFICATION)

NOTE: Measure battery voltage at the battery.

With the engine still running at idle, turn off all accessory loads.

Measure and record:

Positive Lead	Measurement / Action	Negative Lead
Courtesy of FORD MOTOR COMPANY	Courtesy of FORD MOTOR COMPANY	Courtesy of FORD MOTOR COMPANY

Access the PCM and monitor the VPWR (V) PIDand record.

Momentarily accelerate the engine to Wide Open Throttle (WOT) and release. Repeat this step 4-5 times while continuing to monitor the PID.

Does the PID stay within 0.5 volt of the recorded battery voltage when the engine Revolutions Per Minute (RPM) are increased?

Yes	The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. INSPECT and REPAIR any connector or pin issues found. If no connector or pin issues are found, PERFORM the battery drain test. REFER to: Battery Drain Check .

GO to D12

D12 CHECK GENERATOR CLUTCH OPERATION

Ignition OFF.

Perform the generator clutch component test. GO to Pinpoint Test I

Is the generator clutch OK?

Yes	INSTALL a new generator. REFER to: Generator - 2.7L EcoBoost (238kW/324PS) . REFER to: Generator - 3.5L EcoBoost (BM) .

No	INSTALL a new generator clutch. REFER to: Generator - 2.7L EcoBoost (238kW/324PS) . REFER to: Generator - 3.5L EcoBoost (BM) .

D13 CHECK FOR CORRECT DC (DIRECT CURRENT) / AC (ALTERNATING CURRENT) INVERTER OPERATION

Ignition OFF.

Disconnect and inspect all DC / AC inverter 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 DC / AC inverter 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 a loose or corroded connector. ADDRESS the root cause of any connector or pin issues.