Pinpoint Test H : P1839, P1840, P1841

WARNING: This page is about a different car, the 2020 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.

Refer to TWO WHEEL DRIVE/FOUR WHEEL DRIVE SYSTEMS for schematic and connector information.

Normal Operation and Fault Conditions

The electric shift motor is mounted externally to the transfer case. It drives a rotary cam which moves the range and mode forks within the transfer case. The shift motor moves during shifts in to and out of 4H, 4L, and to Neutral. It does not move during the shift between 2H and 4A. TCCM directly controls the electric shift motor and can reverse motor polarity to reverse rotary cam/shift fork direction. The message center may display "Shift in Progress" while the shift motor is operating.

DTC Fault Trigger Conditions

DTC	Description	Fault Trigger Condition
TCCM P1839:00	Transfer Case Shift Motor Open Circuit: No Sub Type Information	This DTC sets when the TCCM detects an open circuit to the shift motor.
TCCM P1840:00	Transfer Case Shift Motor Short Circuit To Battery: No Sub Type Information	This DTC sets when the TCCM detects a short to voltage. Shift motor moves are prevented when this DTC is set.
TCCM P1841:00	Transfer Case Shift Motor Short Circuit To Ground: No Sub Type Information	This DTC sets when TCCM detects a short to ground. Shift motor moves are prevented when this DTC is set.

Possible Sources

MTR-CCW or MTR-CW open circuit
MTR-CCW or MTR-CW circuit short to ground
MTR-CCW or MTR-CW circuit short to voltage
Transfer case shift motor

H1 CHECK THE TRANSFER CASE SHIFT MOTOR CIRCUITS FOR AN OPEN

Disconnect Transfer Case C350.

Disconnect TCCM C2371B.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C2371B-5	Courtesy of FORD MOTOR COMPANY	C350-4
C2371B-4	Courtesy of FORD MOTOR COMPANY	C350-3

Are the resistances less than 3 ohms?

Yes

GO to H2

No	REPAIR the open circuit.

H2 CHECK THE TRANSFER CASE SHIFT MOTOR CIRCUITS FOR SHORT TO VOLTAGE

Disconnect Transfer Case C350.

Disconnect TCCM C2371B.

Ignition ON.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C2371B-5	Courtesy of FORD MOTOR COMPANY	Ground
C2371B-4	Courtesy of FORD MOTOR COMPANY	Ground

Is any voltage present?

Yes	REPAIR the short to power.

GO to H3

H3 CHECK THE TRANSFER CASE SHIFT MOTOR CIRCUITS FOR SHORT TO GROUND

Ignition OFF.

Disconnect Transfer Case C350.

Disconnect TCCM C2371B.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C2371B-5	Courtesy of FORD MOTOR COMPANY	Ground
C2371B-4	Courtesy of FORD MOTOR COMPANY	Ground

Are the resistances greater than 10, 000 ohms?

Yes

GO to H4

No	REPAIR the short to ground.

H4 CHECK THE TRANSFER CASE SHIFT MOTOR FOR SHORT TO GROUND

Ignition OFF.

Connect Transfer Case C350.

Disconnect TCCM C2371B.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C2371B-5	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance greater than 10, 000 ohms?

Yes

GO to H5

No	INSTALL a new transfer case shift motor. REFER to: Transfer Case Shift Motor .

H5 CHECK THE SHIFT MOTOR HI TO LOW CIRCUIT FOR POWER WHILE COMMANDING (CW_SMD_OS) ON

Ignition OFF.

Connect TCCM C2371B.

Disconnect Transfer Case C350.

Ignition ON.

Enter the following diagnostic mode: TCCM Datalogger.

Access the TCCM and control the CW_SMD_OS PID

Measure:

Positive Lead	Measurement / Action	Negative Lead
C350-4	Courtesy of FORD MOTOR COMPANY	Ground

Is battery voltage present when commanding the PID ON?

Yes

GO to H6

No	END Output State Control. GO to H7

H6 CHECK THE SHIFT MOTOR LOW TO HI CIRCUIT FOR POWER WHILE COMMANDING (CCW_SMD_OS) ON

Ignition OFF.

Connect TCCM C2371B.

Disconnect Transfer Case C350.

Ignition ON.

Enter the following diagnostic mode: TCCM Datalogger.

Access the TCCM and control the CCW_SMD_OS PID

Measure:

Positive Lead	Measurement / Action	Negative Lead
C350-3	Courtesy of FORD MOTOR COMPANY	Ground

Is battery voltage present when commanding the PID ON?

Yes	INSTALL a new shift motor. REFER to: Transfer Case Shift Motor .

No	END Output State Control. GO to H7

H7 CHECK THE TCCM VOLTAGE CIRCUITS

Ignition OFF.

Disconnect TCCM C2371B.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C2371B-6	Courtesy of FORD MOTOR COMPANY	Ground
C2371B-7	Courtesy of FORD MOTOR COMPANY	Ground

Is the voltage greater than 11 volts?

Yes

GO to H8

No	VERIFY VBATT fuses for TCCM are OK. If OK, REPAIR the open circuit. If not OK, REFER to the OEM ELECTRICAL WIRING DIAGRAM INTRODUCTION to identify possible causes of the circuit short.

H8 CHECK THE TRANSFER CASE CONTROL MODULE GROUND

Ignition OFF.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C2371B-1	Courtesy of FORD MOTOR COMPANY	Ground
C2371B-3	Courtesy of FORD MOTOR COMPANY	Ground

Are the resistances less than 3 ohms?

Yes

GO to H9

No	REPAIR the open circuit.

H9 CHECK FOR CORRECT TCCM OPERATION

Ignition OFF.

Disconnect and inspect all TCCM connectors.

Check for the following:
- 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

Connect all TCCM connectors. Make sure they seat and latch correctly.

Operate the system and verify the concern is still present.

Is the concern still present?

Yes	INSTALL a new TCCM. REFER to: Transfer Case Control Module (TCCM) .

No	The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector. ADDRESS the root cause of the connector or pin issues.