4X4 Problems
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4X4 Problems
I have a 2001 B4000 Mazda truck. The 4X4 transfer case motor no longer engages, dash light indicator for 2w high, 4w high, and 4w low no longer works. In fact I had to remove the transfer motor and physically engage it back to 2 wheel high. I have checked: fuses, electrically jumped the transfer motor (it works fine), looked at harness connections and I finally located the electronic shift control module after removing the passengers kick panel (Hanes Manual said driver side). The Hanes Manual as far as trouble shooting in this area leaves little to be desired as well as my electrical experience. HELP!
Last edited by Shadetree101; Jul 6, 2005 at 11:06 AM. Reason: Spacing
Post Fiend
Joined: Feb 2003
Posts: 6,940
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From: Eastern WA
I'd say your next step is to get out the VOM and a schematic and trace where the voltage loss is occuring. Personally, I'd start at the switch and see if it's got voltage. By doing this I'd determine whether I needed to work back to the power source or forward and towards the transfer case.
BTW, Haynes does a much better job of making mens underwear than they do repair manuals. They leave a lot to be desired, in particular, DETAIL.
BTW, Haynes does a much better job of making mens underwear than they do repair manuals. They leave a lot to be desired, in particular, DETAIL.
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Originally Posted by CowboyBilly9Mile
I'd say your next step is to get out the VOM and a schematic and trace where the voltage loss is occuring. Personally, I'd start at the switch and see if it's got voltage. By doing this I'd determine whether I needed to work back to the power source or forward and towards the transfer case.
BTW, Haynes does a much better job of making mens underwear than they do repair manuals. They leave a lot to be desired, in particular, DETAIL.
BTW, Haynes does a much better job of making mens underwear than they do repair manuals. They leave a lot to be desired, in particular, DETAIL.
vr Hank
Senior User
Joined: Apr 2002
Posts: 267
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From: Peoria, Il
i had a similar problem on a friends ranger. take the 4x4 engage motor apparts, some plastic bushings go bad and bind up, it works fine off the case but when its attatched it doesnt have enough power to turn the crud and the TC.
Bone
Bone
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Joined: Jan 2003
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From: Connecticut
2002 Transfer Case
FWIW, I was trying to help someone out who had PM'd me a while back about problems he was having with the transfer case on his '02. I assume that your '01 has the "constant engagement" 4x4 system (and not PVH), similar to what the '02 has, so I will set forth my post to him which contains a discussion on how the '02 TC operates, and some info on how to diagnose problems. Hope it helps:
Actually, I'm not really the guy when it comes to '02 4x4 systems since my '98 4x4 system operates a little bit differently from yours. However, I think the transfer case stuff is pretty much the same, so I went ahead and looked over the ‘02 Ford Manual to see if I can pass something along for you to work with. From what I can tell, the problem you seem to be having is either with the Switch or with the 4WD Control Module (located on the RH rocker panel). The reason I suggest that is because the signal from the Switch is sent directly to the 4WD Control Module, and it is then role of the 4WD Control Module to activate the Transfer Case motor using other data input as more fully described below.
The 4WD Control Module is also capable of setting 4x4-related trouble codes which the PCM will store in memory and can be read with an OBD-II scanner that is capable of reading Ford proprietary codes. So for starters, if you can get the codes pulled with a suitable scanner, maybe something will show up and point you in the right direction that way. In the meantime, here is the relevant stuff from the Ford Manual that also might help you diagnose the problem:
Electronic Shift Control System - Overview
Four-wheel drive mode is selected using a rotary switch located on the instrument panel. With the vehicle ignition on, the on-board controller verifies and matches the shift motor position to the switch.
To shift in and out of 4WD low, three conditions must be met:
- The automatic transmission must be in NEUTRAL or the manual clutch depressed.
- The brake must be applied.
- The vehicle speed must be less than 5 km/h (3 mph).
Electric Shift Motor
The motor assembly and connector, mounted externally on the transfer case cover, drives an electric shift cam which moves the lockup fork and the reduction fork assembly to the selected vehicle drive position. An integral position sensor provides information to the electronic module on the current motor position.
Digital Transmission Range (DTR) Sensor
The DTR sensor is located on the outside of the transmission at the manual lever. The DTR sensor completes the start circuit in PARK and NEUTRAL, the reversing lamp circuit in REVERSE and the neutral sense circuit (4x4 only) in NEUTRAL. The DTR sensor also sends a digital output signal to the powertrain control module (PCM) indicating the position of the manual lever (P, R, N, D, 2, 1).
Clutch Pedal Position Switch
The clutch pedal position switch is located on the clutch pedal bracket. On vehicles equipped with manual transmissions, the clutch pedal must be fully depressed with the vehicle stopped in order to make a range shift from 4H to 4L, or from 4L to 4H.
Brake Switch
The brake switch is located on the brake pedal. The brake must be depressed in order to make a range shift from 4WD high to 4WD low or back.
Rotary Control Switch
The rotary control switch is located on the instrument panel. The switch consists of a **** with a night time illuminated pointer. The switch is used to select 2WD, 4WD high or 4WD low. The dash indicator light will illuminate when the 4WD high or low position is engaged.
4WD Control Module, Electronic
The electronic control module controls the operation of the transfer case in response to the inputs from the brake switch, the DTR sensor, the clutch interlock switch, and the motor assembly through the actuation of the rotary control switch.
Principles of Operation
Electronic Shift Control System - Principles of Operation
Transfer Case — Electronic Shift
The system mode is selected by the operator through the mode select switch (MSS) on the instrument panel. Shifts into 4WD HIGH can be made at any speed. When shifting into 4WD HIGH with the vehicle stationary, tooth blockage may occur preventing shift completion. When the vehicle is driven above 8 km/h (5 mph) the shift will complete. When shifting in or out of 4WD LOW, the four-wheel drive (4WD) control module requires that the vehicle speed be less than 5 km/h (3 mph), the brake pedal be applied, and the transmission be in NEUTRAL (automatic transmission) or the clutch pedal be depressed (manual transmission).
The gearmotor encoder assembly is mounted externally on the transfer case. It drives a rotary cam which moves the mode fork and range fork within the transfer case between the 4WD HIGH, 4WD LOW, and 2WD range positions.
The four-wheel drive (4WD) Control Module controls the gearmotor encoder assembly that shifts between 4WD HIGH, 4WD LOW, and 2WD modes.
System Function
Feature inputs:
- brake ON/OFF switch
- mode select switch (MSS)
- digital transmission range (TR) sensor
- vehicle speed signal transmitted from the powertrain control module (PCM)
- TC contact plate position inputs A, B, C, D
Feature outputs:
- 4WD LOW indicator (ground when activated, open circuit when deactivated)
- 4WD indicator (ground when activated, open circuit when deactivated)
- 4WD shift motor outputs
Inspection and Verification — Electronic Shift
Visually inspect the following for obvious signs of mechanical and electrical damage.
Mechanical inspection:
Axle shafts and universal joints
Driveshaft and universal joints
Fluid leaks
Matching tire size
Electrical inspection:
-Battery junction box (BJB) fuses:
- Fuse # 1 (50A)
- Fuse # 3 (50A)
- Fuse # 13 (20A)
- Fuse # 30 (10A)
-Central junction box (CJB) fuses:
- Fuse # 28 (7.5A) (manual transmission)
- Fuse # 10 (7.5A)
- Fuse # 11 (7.5A)
- Fuse ## 5 (15A)
-4WD control module
-Wiring harness
-Mode select switch (MSS)
-Gearmotor encoder assembly
-Connector(s)
-Circuitry
Hope this helps. Good luck, and next time don't be shy about posting in the Ranger Forum, there are a lot of knowledgeable people that hang around there.
Joe
Originally Posted by Rockledge
Actually, I'm not really the guy when it comes to '02 4x4 systems since my '98 4x4 system operates a little bit differently from yours. However, I think the transfer case stuff is pretty much the same, so I went ahead and looked over the ‘02 Ford Manual to see if I can pass something along for you to work with. From what I can tell, the problem you seem to be having is either with the Switch or with the 4WD Control Module (located on the RH rocker panel). The reason I suggest that is because the signal from the Switch is sent directly to the 4WD Control Module, and it is then role of the 4WD Control Module to activate the Transfer Case motor using other data input as more fully described below.
The 4WD Control Module is also capable of setting 4x4-related trouble codes which the PCM will store in memory and can be read with an OBD-II scanner that is capable of reading Ford proprietary codes. So for starters, if you can get the codes pulled with a suitable scanner, maybe something will show up and point you in the right direction that way. In the meantime, here is the relevant stuff from the Ford Manual that also might help you diagnose the problem:
Electronic Shift Control System - Overview
Four-wheel drive mode is selected using a rotary switch located on the instrument panel. With the vehicle ignition on, the on-board controller verifies and matches the shift motor position to the switch.
To shift in and out of 4WD low, three conditions must be met:
- The automatic transmission must be in NEUTRAL or the manual clutch depressed.
- The brake must be applied.
- The vehicle speed must be less than 5 km/h (3 mph).
Electric Shift Motor
The motor assembly and connector, mounted externally on the transfer case cover, drives an electric shift cam which moves the lockup fork and the reduction fork assembly to the selected vehicle drive position. An integral position sensor provides information to the electronic module on the current motor position.
Digital Transmission Range (DTR) Sensor
The DTR sensor is located on the outside of the transmission at the manual lever. The DTR sensor completes the start circuit in PARK and NEUTRAL, the reversing lamp circuit in REVERSE and the neutral sense circuit (4x4 only) in NEUTRAL. The DTR sensor also sends a digital output signal to the powertrain control module (PCM) indicating the position of the manual lever (P, R, N, D, 2, 1).
Clutch Pedal Position Switch
The clutch pedal position switch is located on the clutch pedal bracket. On vehicles equipped with manual transmissions, the clutch pedal must be fully depressed with the vehicle stopped in order to make a range shift from 4H to 4L, or from 4L to 4H.
Brake Switch
The brake switch is located on the brake pedal. The brake must be depressed in order to make a range shift from 4WD high to 4WD low or back.
Rotary Control Switch
The rotary control switch is located on the instrument panel. The switch consists of a **** with a night time illuminated pointer. The switch is used to select 2WD, 4WD high or 4WD low. The dash indicator light will illuminate when the 4WD high or low position is engaged.
4WD Control Module, Electronic
The electronic control module controls the operation of the transfer case in response to the inputs from the brake switch, the DTR sensor, the clutch interlock switch, and the motor assembly through the actuation of the rotary control switch.
Principles of Operation
Electronic Shift Control System - Principles of Operation
Transfer Case — Electronic Shift
The system mode is selected by the operator through the mode select switch (MSS) on the instrument panel. Shifts into 4WD HIGH can be made at any speed. When shifting into 4WD HIGH with the vehicle stationary, tooth blockage may occur preventing shift completion. When the vehicle is driven above 8 km/h (5 mph) the shift will complete. When shifting in or out of 4WD LOW, the four-wheel drive (4WD) control module requires that the vehicle speed be less than 5 km/h (3 mph), the brake pedal be applied, and the transmission be in NEUTRAL (automatic transmission) or the clutch pedal be depressed (manual transmission).
The gearmotor encoder assembly is mounted externally on the transfer case. It drives a rotary cam which moves the mode fork and range fork within the transfer case between the 4WD HIGH, 4WD LOW, and 2WD range positions.
The four-wheel drive (4WD) Control Module controls the gearmotor encoder assembly that shifts between 4WD HIGH, 4WD LOW, and 2WD modes.
System Function
Feature inputs:
- brake ON/OFF switch
- mode select switch (MSS)
- digital transmission range (TR) sensor
- vehicle speed signal transmitted from the powertrain control module (PCM)
- TC contact plate position inputs A, B, C, D
Feature outputs:
- 4WD LOW indicator (ground when activated, open circuit when deactivated)
- 4WD indicator (ground when activated, open circuit when deactivated)
- 4WD shift motor outputs
Inspection and Verification — Electronic Shift
Visually inspect the following for obvious signs of mechanical and electrical damage.
Mechanical inspection:
Axle shafts and universal joints
Driveshaft and universal joints
Fluid leaks
Matching tire size
Electrical inspection:
-Battery junction box (BJB) fuses:
- Fuse # 1 (50A)
- Fuse # 3 (50A)
- Fuse # 13 (20A)
- Fuse # 30 (10A)
-Central junction box (CJB) fuses:
- Fuse # 28 (7.5A) (manual transmission)
- Fuse # 10 (7.5A)
- Fuse # 11 (7.5A)
- Fuse ## 5 (15A)
-4WD control module
-Wiring harness
-Mode select switch (MSS)
-Gearmotor encoder assembly
-Connector(s)
-Circuitry
Hope this helps. Good luck, and next time don't be shy about posting in the Ranger Forum, there are a lot of knowledgeable people that hang around there.
Joe
Very good stuff.
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