Pinpoint Test F: Can Communications Bus Fault
WARNING: This page is about a different variant/trim than selected.
NOTE:
Conduct steps 1-7 outlined in Inspection and Verification prior to performing this test.
- F1 CHECK FOR DTCs U1900, U0100 AND U0121 SET TOGETHER
- Refer to the results of the 4WD control module self-test.
- Are DTCs U1900, U0100 and U0121 set together?
- Yes : REFER to MODULE COMMUNICATIONS NETWORK to continue diagnosis of the communications network.
- No : GO to F2.
- F2 CHECK FOR DTC U0100
- Refer to the results of the 4WD control module self-test.
- Is DTC U0100 set, but not U1900?
- Yes : The PCM is not sending any data to the 4WD control module. Refer to INTRODUCTION - GASOLINE article for Escape (gasoline) and Mariner or INTRODUCTION- HYBRID ESCAPE article for Escape (Hybrid) for additional PCM diagnosis.
- No : GO to F3.
- F3 CHECK FOR DTC U0121
- Refer to the results of the 4WD control module self-test.
- Is DTC U0121 set, but not U1900?
- Yes : The ABS module is not sending any data to the 4WD control module. REFER to ANTI-LOCK CONTROL for additional ABS diagnosis.
- No : GO to F4.
- F4 CHECK FOR CORRECT 4WD CONTROL MODULE OPERATION
- Disconnect the 4WD control module.
- Check for:
- corrosion
- pushed-out pins
- Connect the 4WD control module and make sure it seats correctly.
- Operate the system and determine if the concern is still present.
- Is the concern still present?
- Yes : INSTALL a new 4WD control module. REFER to FOUR-WHEEL DRIVE (4WD) CONTROL MODULE . CLEAR the DTCs. REPEAT the self-test.
- No : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.