Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2003 Lincoln Navigator RWDFACTORY OEM SERVICE PROCEDURE
Transfer Case DTCS
TRANSFER CASE (4WD CONTROL MODULE) DIAGNOSTIC TROUBLE CODE (DTC) LIST
| DTC | Description | Source | Action |
|---|---|---|---|
| B1317 | Battery Voltage High | 4WD control module | CHECK the battery and charging system. REFER to GENERATORS & REGULATORS . |
| B1318 | Battery Voltage Low | 4WD control module | CHECK the battery and charging system. REFER to GENERATORS & REGULATORS . |
| B1342 | ECU is Defective | 4WD control module | CLEAR the DTCs. REPEAT the 4WD control module self-test. If DTC B1342 is retrieved, INSTALL a new 4WD control module. REFER to FOUR-WHEEL DRIVE (4WD) CONTROL MODULE . CLEAR the DTCs. REPEAT the self-test. |
| B2105 | Throttle Position Input Out of Range Low | 4WD control module | Go To PINPOINT TEST A . |
| B2106 | Throttle Position Input Out of Range High | 4WD control module | Go To PINPOINT TEST A . |
| C1728 | Transfer Case Unable to Transition Between 2H and 4H. | 4WD control module | Go To PINPOINT TEST C . |
| C1729 | Transfer Case Unable to Transition Between 4WD HIGH and 4WD LOW | 4WD control module | Go To PINPOINT TEST C . |
| C1979 | IWE Solenoid Circuit Failure | 4WD control module | Go To PINPOINT TEST A . |
| C1980 | IWE Solenoid Short to Battery | 4WD control module | Go To PINPOINT TEST A . |
| P1812 | Transmission 4-Wheel Drive Mode Select Circuit Failure | 4WD control module | Go To PINPOINT TEST A . |
| P1815 | Transmission 4-Wheel Drive Mode Select Short Circuit to Ground | 4WD control module | Go To PINPOINT TEST A . |
| P1824 | Transmission 4-Wheel Drive Clutch Relay Circuit Failure | 4WD control module | Go To PINPOINT TEST A . |
| P1826 | Transmission 4-Wheel Drive Low Clutch Relay Short Circuit to Battery | 4WD control module | Go To PINPOINT TEST A . |
| P1827 | Transmission 4-Wheel Drive Low Clutch Relay Short Circuit to Ground | 4WD control module | Go To PINPOINT TEST A . |
| P1849 | Transmission Transfer Case Contact Plate A Short Circuit to Ground | 4WD control module | Go To PINPOINT TEST C . |
| P1853 | Transmission Transfer Case Contact Plate B Short Circuit to Ground | 4WD control module | Go To PINPOINT TEST C . |
| P1857 | Transmission Transfer Case Contact Plate C Short Circuit to Ground | 4WD control module | Go To PINPOINT TEST C . |
| P1861 | Transmission Transfer Case Contact Plate D Short Circuit to Ground | 4WD control module | Go To PINPOINT TEST C . |
| P1867 | Transmission Transfer Case Contact Plate General Circuit Failure | 4WD control module | Go To PINPOINT TEST C . |
| P1891 | Transmission Transfer Case Contact Plate Ground Return Open Circuit | 4WD control module | Go To PINPOINT TEST C . |
| U1900 | CAN Communication BUS Fault | 4WD control module | REFER to MODULE COMMUNICATIONS NETWORK . |
| U1950 | UBP Communication BUS Fault | 4WD control module | REFER to MODULE COMMUNICATIONS NETWORK . |
| U2023 | External Node Fault | 4WD control module | REFER to MODULE COMMUNICATIONS NETWORK . |
| U2306 | Invalid UBP Data From Instrument Cluster (Node 60) | 4WD control module | REFER to MODULE COMMUNICATIONS NETWORK . |
| U2226 | Invalid UBP Data From PCM (Node 10) | 4WD control module | REFER to MODULE COMMUNICATIONS NETWORK . |
| - | For All Other DTCs | 4WD control module | REFER to MULTIFUNCTION ELECTRONIC MODULE . |
Factory Service Tools
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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