LET S PLAY BALL. Stuck in

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Philip Daniel
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1 LET S PLAY BALL Stuck in 4 GEARS March 2004

4X4 by Lance Wiggins By now, most you are thawing out from the winter, football is long gone, and hockey is on your mind.

There s obviously a huge difference between the southwest and the northeast, and between football and hockey. But they do have something in common: Sports and 4X4s.

In the northeast, snow and ice are problems; on the west coast, well, it s the sand and mud.

Ford s ESOF System Ford s ESOF systems have been around since the 80s. This system allows the driver to switch from 2WD to 4WD, while driving at speeds up to 45 MPH.

2 4X4 by Lance Wiggins By now, most you are thawing out from the winter, football is long gone, and hockey is on your mind. And to think, some of our friends in the New England states were shivering as the mercury dropped to -30ºF just two months ago! While at the same time, we were basking in 80ºF sun. There s obviously a huge difference between the southwest and the northeast, and between football and hockey. But they do have something in common: Sports and 4X4s. We may disagree on which sport is better, but one thing remains the same: We both have 4X4 problems this time of year. In the northeast, snow and ice are problems; on the west coast, well, it s the sand and mud. In this issue of Let s Play Ball, we re going to cover some very common problems with the Ford ESOF (Electronic Shift On the Fly) transfer case systems. Ford s ESOF System Ford s ESOF systems have been around since the 80s. This system allows the driver to switch from 2WD to 4WD, while driving at speeds up to 45 MPH. The ESOF system really evolved from the harsh winters in the northeast. Let s face it: who wants to stop, move a couple of levers, then get out of the truck to lock the hubs just to get into 4X4 operation, all at -30ºF? Uh Nobody! The answer? Automatic hubs and shift on the fly. Allowing the driver to shift into 4WD without leaving the comfort of the cab was a hit, but what happens when things go wrong? Let s take a look Stuck in 4X4, Erratic 4X4 Operation Vehicles between the years of have experienced a wide range of problems: Erratic 4X4 Hi operation Low shift events 4X4 or Low Range indicator flashing or stays lit Vehicle stuck in 4L after an uncommanded shift GEARS March

associated with a faulty 4X4 shift motor.

The new shift motor (part # YL1Z-7G360-AA) has a gray contact plate cover, and it replaces the earlier motor that

The gray-cover shift motors contain improved sense plate material and shift motor terminal upgrades, to help

These conditions can cause all kinds of problems and create symptoms that normally would seem hard to find.

turning Clunking or grinding noises Low range light turns on If the Generic Electronic Module (GEM) receives a

you could experience an uncommanded shift if all of the other switch conditions are met (figure 2a, 2b, 2c, 2d).

3 Stuck in 4X4 New Shift Motor. Part # YLIZ-7G360-AA Figure 1A Figure 1B Figure 2A Figure 2B Figure 2C Figure 2D All of these problems have been associated with a faulty 4X4 shift motor. Ford recently came out with a new motor to repair these problems (figure 1a, 1b). The new shift motor (part # YL1Z-7G360-AA) has a gray contact plate cover, and it replaces the earlier motor that had a blue contact plate cover (part # F75Z-7G360-AA). The gray-cover shift motors contain improved sense plate material and shift motor terminal upgrades, to help combat the harsh elements like water, snow, mud, rock, salt, rust, etc you get the idea. These conditions can cause all kinds of problems and create symptoms that normally would seem hard to find. Uncommanded Shift to 4L Parking maneuvers or gear lever transitions during low speeds can cause an uncommanded shift to 4L. Symptoms include: Front end binding or hopping while turning Bind feel in the drivetrain when backing up or turning Clunking or grinding noises Low range light turns on If the Generic Electronic Module (GEM) receives a false mode switch input during, or shortly after, the Digital Transmission Range Sensor (DTR) indicates neutral, you could experience an uncommanded shift if all of the other switch conditions are met (figure 2a, 2b, 2c, 2d). These conditions (besides transmission in neutral) include: Service brake depressed Figure 3 Vehicle speed less than 3 MPH A false switch input may also set a P1812 (4-Wheel Drive Mode, Select Circuit Failure, figure 3) or P1815 (4-wheel drive mode select short circuit to ground) DTC in the GEM. Check for any of these conditions in the mode switch wiring (figure 4): Circuit 682 (dark blue wire) shorted to power Circuit 780 (dark blue wire) shorted to ground Loose connections at the 6 GEARS March 2004

Ask your supplier about the NEW Z Pak! Now Available Z pak is the patented, single-sided design clutch system that outperforms OE in torque and heat capacity without coning.

4 Ask your supplier about the NEW Z Pak! Now Available Z pak is the patented, single-sided design clutch system that outperforms OE in torque and heat capacity without coning. Z Pak is just one way Raybestos is aggressively leading the industry in introducing innovative technologies. Patent pending. 4L60/4L60E/4L65E 3-4 Clutch Assembly 964 East Market St., Crawfordsville, IN Toll Free: Fax: raypt@raybestospowertrain.com

Stuck in 4X4 Figure 4 inline connectors Chafed or damaged wiring Use your scan tool to monitor the mode switch Parameter Identification Display for 4WD_Switch (figure 5) for false readings, while

You may have to delete a number of PIDs and only choose a couple during this test; in some cases the problem may be so short-lived that your scan tool can t pick up the failure.

6 Stuck in 4X4 Figure 4 inline connectors Chafed or damaged wiring Use your scan tool to monitor the mode switch Parameter Identification Display for 4WD_Switch (figure 5) for false readings, while gently pushing in and wiggling the mode switch knob. You may have to delete a number of PIDs and only choose a couple during this test; in some cases the problem may be so short-lived that your scan tool can t pick up the failure. Replace the mode switch if it fails testing, or repair wiring on circuits 682 or 780 if they seem to be at fault. If everything else is okay, inspect the build date stamped on the GEM. Replace the GEM if it was built before 9/98. Test drive the vehicle for proper 4X4 operation in all modes. Include parking lot maneuvers and transmission gear range lever transitions. Check for codes in the GEM. Clear any codes present, and cycle the ignition. Road Speed Symptoms for a higher speed (over 25 MPH) uncommanded shift to 4L include: Rapid deceleration High engine revving, possibly accompanied by code P1270 (Engine RPM or Vehicle Limiter Reached) in the PCM Clunking or grinding noise Speedometer may spike higher than actual speed After the initial event, the vehicle may exhibit restricted vehicle top speed without 4X4 indicators lit, but the MIL (Malfunction Indictor Lamp) may be turned on. In most cases, this condition is related to a wiring failure between the GEM and the 4x4 shift motor or connector. Using your scan tool, monitor Figure 5 the contact plates. On your scan tool display, the contact plates will be listed as A, B, C, and D. Read the PIDs in order, starting with plate A, then B, then C, and finally D. With mode switch pushed in: A4WD plate PIDs should read O C O O 4H PIDs should read C O O C 4L PIDs should read C O C O NOTE: O = Open and C = Closed If the contact plate s parameters don t correspond to the set 4WD positions, check for continuity, shorts, moisture or corrosion in the vehicle side of the transfer case shift motor connector, toward the GEM. Visually inspect all of the terminals, pins, GEARS March

Stuck in 4X4 crimps, and connectors closely. Repair any wiring problems in the contact plate circuits as necessary. The most common area for a circuit problem is the shift motor connector.

7 Stuck in 4X4 crimps, and connectors closely. Repair any wiring problems in the contact plate circuits as necessary. The most common area for a circuit problem is the shift motor connector. After repair, road test the vehicle above 10 MPH with the mode switch set to both A4WD and 4H, to see if the condition returns. Clear any codes from the GEM and cycle the ignition. Clear codes from the PCM if a P1270 (Engine RPM or Vehicle Speed Limiter Reached) code was initially present. Autolock Strategy (Expedition/ Navigator Vehicles Only) If the vehicle was driven off-road or under slippery conditions, it may cause an uncommanded 4H shift with the red 4X4 light on constantly while driving in Automatic Mode. This condition is known as Autolock strategy and is commanded by the GEM. The GEM Autolock strategy commands the transfer case clutch to minimum duty cycle, and engages 4H, with the mode switch still set to A4WD. This is to prevent continuous cycling, which could cause premature clutch wear. Excessive differences in tire size or axles with unmatched gear ratios can also cause unexpected Autolock operation. There are many tools available for checking tire circumference and runout; this tool will cut hours off your diagnostic time. Once the condition that caused the Autolock strategy is no longer present, the system stays in 4H until you cycle the ignition key or set the mode switch to 4H, and then back to A4WD. Transfer Case Speed Sensors (Expedition/ Navigator Vehicles Only) If an uncommanded shift to 4H occurs on hi-traction surfaces, check for excessive variation between the signals from the TRA_FSP (Transfer Case Front Speed Sensor) and TRA_RSP (Transfer Case Rear Speed Sensor) PIDs. On your scan tool display, both sensors should indicate speeds within 1-2 MPH of each other during steady driving speeds. If not, check for codes P1836 ( Transfer Case Front Speed Sensor) and P1837 (Transfer Case Rear Speed Sensor). If these codes aren t present, start with these easy diagnostic steps: Make sure tire pressures are even Check the tire sizes circumferences should be within 1/4 between all four tires Make sure front and rear axle gear ratios match If the ratios match and tire sizes and pressures are okay, check all of the associated circuits. If the wiring checks out okay, replace the speed sensor(s). In most cases, replacing the sensors will fix the problem. After any repairs, road test the vehicle while comparing GEM PIDs for both transfer case speed sensors to PCM vehicle speed sensor signal. Verify all three PIDs match within 1-2 MPH. Mode Switch The mode switch is simply the transfer case switch on the dash. A false mode switch input on circuits 682 or 780 (dark blue wire) could be interpreted by the GEM as the driver requesting a 4H shift. If that happens, the GEM will command shift motor movements to match the false switch input. The red 4X4 indicator light will light, just as if you moved the switch. If the condition becomes intermittent, the 4X4 range and indicators could switch back and forth between 2H, A4WD and 4H, causing an audible grinding noise and possible jerking sensation. The easiest way to diagnose this system is to remove the mode switch from the dash. Check the mode switch circuits between the GEM and dash for chafing, shorts, crimps, and continuity. Repair the wiring as necessary. If the wiring is okay, replace the mode switch itself. After any repair, clear the codes from the GEM. Always go through the ritual of clearing codes. Stuck in 4X4 Low All the Time Customers describe this as an uncommanded shift to 4L shortly after startup, and are then unable to shift the transfer case. Associated symptoms could include valid GEM codes being erased and false codes such as C1107 (4WABS Module Failure). If the transfer case is stuck in 4X4 Low and the mode switch is in A4WD or 2WD, try to restore normal shift motor operation by putting the mode switch in 4L with the: transmission gear lever in neutral service brake depressed vehicle stopped If the transfer case motor returns to normal operation, reprogram or replace the GEM. The GEM program has been updated to correct this condition. If the GEM needs to be replaced, the new one should already have the updated programming. That s it! Hopefully this article will help you chase down some of the more common problems associated with Ford s ESOF system. After all, who wants to be guessing why your customer is stuck in 4L when it s -30ºF outside brr! Speaking of -30 F, the picture below was probably the first true locking 4x4 locking to the skis that is. And That s the Game! Snow Scene: Model T trucks were often converted into "Snowmobiles," as some were called, for wintertime use. In this 1926 photo, sled runners are attached to the front axle, while a third axle and belt provide increased rear traction. From the collections of Henry Ford Museum & Greenfield Village. 10 GEARS March 2004

SERVICE DIAGNOSTIC INFORMATION. (Yes/No) Symptom(s) DTCs Stored In GEM (And/Or) Potential Cause Procedure

SERVICE DIAGNOSTIC INFORMATION. (Yes/No) Symptom(s) DTCs Stored In GEM (And/Or) Potential Cause Procedure LAMP 4X4 LAMP FLASHING AND 4X4 Article No. INOPERATIVE VEHICLES WITH A4WD 99-14-2 TRANSMISSION AND 4.0L TRANSMISSION A4WD 4X4 LAMP FLASHING AND 4X4 INOPERATIVE VEHICLES WITH 4.0L FORD: 1997-1999 EXPLORER