Inspection and Verification

WARNING: This page is about a different car, the 2006 Mercury Mariner and 2006 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.

Verify the customer concern.

Inspect for obvious signs of mechanical or electrical damage.

VISUAL INSPECTION CHART

Mechanical	Electrical
Active torque coupling Transfer case Halfshafts and constant velocity (CV) joints Driveshaft and universal joints Fluid leaks Wheel/tire size and brand Matching tire size and brand Tire pressure	Smart junction box (SJB) fuse(s): 18 (10A) 35 (5A) Four-wheel drive (4WD) control module Wiring harness Connector(s) Circuitry

If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
If the cause is not visually evident, connect the diagnostic tool to the data link connector and select the vehicle to be tested from the diagnostic tool menu. If the diagnostic tool does not communicate with the vehicle:
- check that the program card is correctly installed.
- check the connections to the vehicle.
- check the ignition switch position.
If the diagnostic tool still does not communicate with the vehicle, refer to the diagnostic tool operating manual
Carry out the diagnostic tool data link test. If the diagnostic tool responds with:
- CAN circuit fault; all electronic control units no response/not equipped, refer to MODULE COMMUNICATIONS NETWORK .
- No response/not equipped for 4WD control module, GO to PINPOINT TEST B .
- System passed, retrieve and record the continuous diagnostic trouble codes (DTCs), erase the continuous DTCs, and carry out the self-test diagnostics for the 4WD control module.
If the DTCs retrieved are related to the concern, go to the FOUR-WHEEL DRIVE (4WD) CONTROL MODULE DIAGNOSTIC TROUBLE CODE (DTC) INDEX .
If no DTCs related to the concern are retrieved, carry out the Functional Test, and GO to PINPOINT TEST A .

FOUR-WHEEL DRIVE (4WD) CONTROL MODULE DIAGNOSTIC TROUBLE CODE (DTC) INDEX

DTC	Description	Possible Causes	Source	Action
B1317	Battery Voltage High	Concern with voltage regulator on generator	4WD Control Module	GO to PINPOINT TEST C .
B1318	Battery Voltage Low	Blown fuse (B+) Intermittent open on power circuit Relay failure inside module	4WD Control Module	GO to PINPOINT TEST C .
B1342	ECU is Defective	Microprocessor or internal memory fault	4WD Control Module	CLEAR the DTCs. REPEAT the self-test. If DTC B1342 is retrieved again, INSTALL a new 4WD control module. REFER to FOUR WHEEL DRIVE (4WD) CONTROL MODULE in this article.
P1635	Tire/Axle Out of Acceptable Range	Wrong size tire installed on vehicle Wheel speed sensor failure Flat or under inflated tire	4WD Control Module	GO to PINPOINT TEST J .
P1824	4WD Clutch Relay Circuit Failure	Short to ground on active torque coupling high circuit Electronic control unit (ECU) failure	4WD Control Module	CHECK SJB fuse 18 (10A). If the fuse is good, GO to PINPOINT TEST G .
P1825	4WD Clutch Relay Open Circuit	Short to ground on active torque coupling high circuit Short to ground on active torque coupling low circuit Open coil inside active torque coupling Open in active torque coupling low circuit Short to voltage in active torque coupling low circuit ECU failure	4WD Control Module	CHECK SJB fuse 18 (10A). If the fuse is good, GO to PINPOINT TEST G .
U0100	Lost Communication with PCM	Controller area network (CAN) bus fault No data received by 4WD control module from powertrain control module (PCM)	4WD Control Module	GO to PINPOINT TEST F .
U0121	Lost Communication with Anti-lock Brake System (ABS)	CAN bus fault No data received by 4WD control module from ABS	4WD Control Module	GO to PINPOINT TEST F .
U0401	Invalid Data Received From PCM	Invalid data received from PCM Data out of range	4WD Control Module	GO to PINPOINT TEST D .
U0415	Invalid Data Received From ABS	Invalid data received from ABS module Data out of range	4WD Control Module	GO to PINPOINT TEST E .
U1900	CAN Communication Bus Fault	CAN bus fault	4WD Control Module	GO to PINPOINT TEST F .