Buddies '02 B4000 4x4 stopped working, trying to help him
#1
11-21-2013, 04:07 PM
Buddies '02 B4000 4x4 stopped working, trying to help him
Hey guys, full disclosure here. I'm not a ford guy 
Never owned or wrenched on one, so I'm a rook when it comes to these things. And for that much more of a problem maker then a mechanic :P But beer is involved so I told him I'd try to help him out.
He has a 02 B4000, not sure of engine, but it's an auto trans with the dial 4x4 switch on the dash. He says the 4x4 just stopped working, right before it snows. Go figure. But no action at all when you enable 4x4.
He doesn't have any repair manuals, cheap or good. Which sucks (I won't go anywhere without my Toyota FSM for my land cruiser), so what would you guys recommend? Grab a book or just dig through some threads/faqs online?
I'm assuming there are some vacuum lines running around or something to look at? Is there a troubleshooting procedure for this kind of issue?
Currently digging through some search results
Thanks!
Never owned or wrenched on one, so I'm a rook when it comes to these things. And for that much more of a problem maker then a mechanic :P But beer is involved so I told him I'd try to help him out.He has a 02 B4000, not sure of engine, but it's an auto trans with the dial 4x4 switch on the dash. He says the 4x4 just stopped working, right before it snows. Go figure. But no action at all when you enable 4x4.
He doesn't have any repair manuals, cheap or good. Which sucks (I won't go anywhere without my Toyota FSM for my land cruiser), so what would you guys recommend? Grab a book or just dig through some threads/faqs online?
I'm assuming there are some vacuum lines running around or something to look at? Is there a troubleshooting procedure for this kind of issue?
Currently digging through some search results
Thanks!
#2
11-22-2013, 07:49 AM
The '02 Ranger 4WD doesn't use vacuum, so it's most likely it's a problem with the transfer case. Any blinking 4WD lights on the dash?
Principles of Operation
Transfer Case — Electronic Shift
The four-wheel drive electronic shift-on-the-fly feature electrically shifts the vehicle transfer case between 2WD, 4WD HIGH, and 4WD LOW. The system mode is selected by the operator through the mode select switch (MSS) on the instrument panel. The operator is informed which mode the system is in by two instrument cluster indicators: one for 4WD HIGH which appears as 4WD, and one for 4WD LOW, which appears as 4WD LOW. 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)
- contact plate position inputs A, B, C, D
System Function - 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
Shifts between 2WD and 4WD HIGH can be made at any speed. Listed below are the inputs and outputs needed by the 4WD control module to execute a change between any of these modes.
Feature inputs:
- vehicle speed signal
- mode select switch
Feature outputs:
- 4WD cluster indicator (ground when activated, open circuit when deactivated)
When shifting into or out of LOW range, the 4WD control module requires that the vehicle speed is less than 5 km/h (3 mph), the brake is applied, and the transmission is in NEUTRAL.
Feature inputs:
- mode select switch
- contact plate position inputs A, B, C, D
- vehicle speed signal
- brake ON/OFF switch input (battery voltage when brake is depressed, open - circuit when not activated)
- digital TR sensor (ground when transmission is in NEUTRAL, open circuit otherwise)
Feature outputs:
- 4WD shift motor outputs
- 4WD LOW cluster indicator (ground when activated, open circuit when deactivated)
Inspection and Verification — Electronic Shift
Visually inspect the following for obvious signs of mechanical and electrical damage:
Mechanical:
- axle shafts and universal joints
- Driveshaft and universal joints
- Fluid leaks
- Matching tire size
- Battery junction box (BJB) fuse:
1 (50A)
3 (50A)
13 (20A)
30 (10A)
- Central junction box (CJB) fuse:
28 (7.5A) (manual transmission)
10 (7.5A)
11 (7.5A)
5 (15A)
- 4WD control module
- Wiring harness
- Mode select switch (MSS)
- gearmotor encoder assembly
- Connector(s)
- Circuitry
Transfer Case — Electronic Shift
The four-wheel drive electronic shift-on-the-fly feature electrically shifts the vehicle transfer case between 2WD, 4WD HIGH, and 4WD LOW. The system mode is selected by the operator through the mode select switch (MSS) on the instrument panel. The operator is informed which mode the system is in by two instrument cluster indicators: one for 4WD HIGH which appears as 4WD, and one for 4WD LOW, which appears as 4WD LOW. 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)
- contact plate position inputs A, B, C, D
System Function - 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
Shifts between 2WD and 4WD HIGH can be made at any speed. Listed below are the inputs and outputs needed by the 4WD control module to execute a change between any of these modes.
Feature inputs:
- vehicle speed signal
- mode select switch
Feature outputs:
- 4WD cluster indicator (ground when activated, open circuit when deactivated)
When shifting into or out of LOW range, the 4WD control module requires that the vehicle speed is less than 5 km/h (3 mph), the brake is applied, and the transmission is in NEUTRAL.
Feature inputs:
- mode select switch
- contact plate position inputs A, B, C, D
- vehicle speed signal
- brake ON/OFF switch input (battery voltage when brake is depressed, open - circuit when not activated)
- digital TR sensor (ground when transmission is in NEUTRAL, open circuit otherwise)
Feature outputs:
- 4WD shift motor outputs
- 4WD LOW cluster indicator (ground when activated, open circuit when deactivated)
Inspection and Verification — Electronic Shift
Visually inspect the following for obvious signs of mechanical and electrical damage:
Mechanical:
- axle shafts and universal joints
- Driveshaft and universal joints
- Fluid leaks
- Matching tire size
- Battery junction box (BJB) fuse:
1 (50A)
3 (50A)
13 (20A)
30 (10A)
- Central junction box (CJB) fuse:
28 (7.5A) (manual transmission)
10 (7.5A)
11 (7.5A)
5 (15A)
- 4WD control module
- Wiring harness
- Mode select switch (MSS)
- gearmotor encoder assembly
- Connector(s)
- Circuitry
#4
11-22-2013, 11:17 AM
Ok some more info, right now the switch is disconnected from the ECM (?) down by the passenger kick panel. I didn't realize the switch was unplugged yesterday the few minutes I was in there. That's why it was dead, it does work.
When it gets plugged in, it just always is grumbling or trying to shift. Sometimes he ends up in neutral, sometimes in 4lo. Right now I think the computer thinks he's in 4lo because the speedo is reading way too fast.
We're going for a ride for lunch, I'll have a listen.
Thanks for the tech info! Just what I was looking for.
When it gets plugged in, it just always is grumbling or trying to shift. Sometimes he ends up in neutral, sometimes in 4lo. Right now I think the computer thinks he's in 4lo because the speedo is reading way too fast.
We're going for a ride for lunch, I'll have a listen.
Thanks for the tech info! Just what I was looking for.
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