Pinpoint Test Ac: DTC P187C:00 And P187D:00

WARNING: This page is about a different car, the 2014 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Make sure the battery is fully charged before carrying out this pinpoint test.

AC1 CHECK FOR TCCM DTCs
NOTE: Failure to place the MSS in 2H or OFF prior to carrying out a self-test of the TCCM (to disable the ELD field coil) results in inaccurate self-test.
- Ignition ON.
- Set the MSS in 2H (ESOF or 2 speed-torque-on-demand).
- Set the MSS in OFF (2WD ).
- Enter the following diagnostic mode on the scan tool: Self-Test - TCCM .
Are any DTCs present?
- Yes : For DTC P187C:00, GO to AC4.
  For DTC P187D:00, GO to AC2 .
  
  For all other DTCs, REFER to the TCCM DTC CHART .
- No : IDENTIFY the customer concern and GO to SYMPTOM CHART - ELECTRONIC LOCKING DIFFERENTIAL (ELD) SYSTEM .
AC2 CHECK FOR TCCM DTCs WITH THE ELD FIELD COIL DISCONNECTED
- Ignition OFF.
- Disconnect: ELD Field Coil.
- Ignition ON.
- Set the MSS in 2H (ESOF or 2 speed-torque-on-demand).
- Set the MSS in OFF (2WD ).
- Enter the following diagnostic mode on the scan tool: Self-Test - TCCM .
CLEAR the DTCs. REPEAT the self-test. Does DTC P187D:00 return?
- Yes : GO to AC3 .
- No : INSTALL a new field coil. REFER to REAR DRIVE AXLE/DIFFERENTIAL - FORD 9.75-INCH RING GEAR . CLEAR the DTCs. TEST the system for normal operation.
AC3 CHECK THE ELD DIFFERENTIAL LOCK CONTROL CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: TCCM C2371B .
- Measure the resistance between TCCM C2371B-9 , circuit CCF31 (BN/VT), harness side and ground.
  
  Fig 1: Measuring Resistance Between TCCM C2371B-9, Circuit CCF31 (BN/VT), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
Is the resistance greater than 10, 000 ohms?
- Yes : GO to AC4 .
- No : REPAIR circuit CCF31 (BN/VT). CLEAR the DTCs. TEST the system for normal operation.
AC4 CHECK THE ELD DIFFERENTIAL LOCK CONTROL CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect: TCCM C2371B .
- Disconnect: ELD Field Coil.
- Measure the resistance between TCCM C2371B-9 , circuit CCF31 (BN/VT), harness side and ELD field coil C4359-1 , circuit CCF31 (BN/VT), harness side.
  
  Fig 2: Measuring Resistance Between TCCM C2371B-9 And ELD Field Coil C4359-1
  Courtesy of FORD MOTOR CO.
Is the resistance less than 3 ohms?
- Yes : GO to AC5 .
- No : REPAIR circuit CCF31 (BN/VT). CLEAR the DTCs. TEST the system for normal operation.
AC5 CHECK FOR CORRECT TCCM OPERATION
- Ignition OFF.
- Disconnect and inspect all TCCM 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
- Connect all TCCM connectors. Make sure they are seated 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) . TEST the system for normal operation.
- 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.