Pinpoint Test L: DTC U041A, U061E

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.

Normal Operation and Fault Conditions

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 auxiliary battery isolator circuit is open.

DTC Fault Trigger Conditions

DTC	Description	Fault Trigger Condition
PCM U041A:00	Invalid Data Received From Battery Isolation/Voltage Stabilization Control Module: No Sub Type Information	Sets when the PCM receives invalid data from the battery isolation / voltage stabilization control module.
PCM U061E:00	Loss of Communication with Battery Isolation/Voltage Stabilization 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 auxiliary battery isolator circuit is open.

Possible Sources

Auxiliary battery isolator
PCM
Wiring, terminals or connectors

Visual Inspection and Pre-checks

Inspect high current BJB for loose, damaged or corroded connections.
Inspect the BJB fuse 8 (20A).

NOTE: Make sure main 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.

L1 CHECK THE AUXILIARY BATTERY ISOLATOR LIN (LOCAL INTERCONNECT NETWORK) CIRCUIT FOR A SHORT TO VOLTAGE

Ignition OFF.

Disconnect Auxiliary battery isolator C102B.

Disconnect PCM C175B.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C159-4	Courtesy of FORD MOTOR COMPANY	Ground

Is any voltage present?

Yes	REPAIR the circuit.

GO to L2

L2 CHECK THE AUXILIARY BATTERY ISOLATOR LIN (LOCAL INTERCONNECT NETWORK) CIRCUIT FOR A SHORT TO GROUND

Ignition OFF.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C159-4	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance greater than 10, 000 ohms?

Yes

GO to L3

No	REPAIR the circuit.

L3 CHECK THE AUXILIARY BATTERY ISOLATOR LIN (LOCAL INTERCONNECT NETWORK) CIRCUIT FOR AN OPEN

Measure:

Positive Lead	Measurement / Action	Negative Lead
C159-4	Courtesy of FORD MOTOR COMPANY	C1381B-11

Is the resistance less than 3 ohms?

Yes	INSTALL a new generator. REFER to: Auxiliary Battery Isolator . REPEAT the PCM self-test. If DTC U061E is retrieved again, GO to K2

No	REPAIR the affected circuit.

L4 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.