TRANSFER CASE (TOD) 5D2-15
DIAGNOSIS
While the TCCU is active it periodically monitors its inputs and outputs. If a fault is detected the “4WD CHECK ” lamp
is illuminated and a fault code is stored in the TCCU memory.
When requested, fault codes are downloaded to a diagnostic connector (K-line) serial communications using SCAN- 100. DIAGNOSTIC TESTS 1.TCCU Internal Function
When the Ignition is turned on the TCCU tests its ROM and RAM. If there is a fault, the TCCU immediately resets itself and re-tests the ROM and RAM. If the fault persists the TCCU continues to reset and re-test until the fault is corrected or the ignition is turned off. All TCCU functions are inhibited until the fault is corrected. The “4WD
CHECK ” lamp is not illuminated if there is a ROM or RAM fault.
If the ROM/RAM passes the EEPROM memory is tested. If there is a fault the “4WD CHECK ” lamp is illuminated
and the TCCU continues to operate using the default calibration data stored in ROM. Fault codes are not storedwhen there is an EEPROM fault.
An EEPROM fault can only be cleared by cycling ignition off-on.
2.Shift Motor Assembly Test If the TCCU detects a shift motor or position encoder fault continuously for one second the ‘4WD CHECK ” lamp is
turned on and the appropriate fault code is stored in memory.
a. A shift motor fault when the motor is off is defined as follows:
Motor H-L shorted to GroundMotor L-H shorted to GroundMotor open circuit
b. A shift motor fault when the motor is energized is defined as follows: Motor H-L shorted to GroundMotor L-H shorted to GroundMotor H-L shorted to Motor L-H Motor open circuit
c. A position encoder fault is defined as follows: Any position code which does not correspond to the valid 9 codes. A short to ground on any of the encoder lines.
d. If no shifts are in progress when a failure occurs the TCCU will not respond to any shift commands.
e. If a shift command has been received, but not acted upon when a failure occurs the TCCU will cancel the command and not respond to any subsequent shift commands.
f. If a shift command is in progress when an invalid position code is confirmed it will be halted and the TCCU will turn the motor toward the high position. Afterwards the TCCU will not respond to any shift commands.
5D2-16 TRANSFER CASE (TOD)g. If the shift motor/position encoder assembly failure (other than a motor failure which occurs when the motor isenergized) recovers continuously for one second the TCCU will function normally. The “4WD CHECK ” lamp is
turned off but the fault code will remain in memory.
h. A motor failure (i.e. open or short circuit) which occurs when the motor is energized can only be cleared by cycling the ignition off-on.
3. Front Speed Sensor Test If a Front Speed Sensor fault is detected continuously for 0.5 second the “4WD CHECK ” lamp is illuminated. The
TCCU then responds as follows:
a. If the system is in High Range the TCCU uses the Rear Speed Sensor to determine the EMC Touch Off level and wheel slip control is suspended.
b. If the system is in Low Range, the EMC Duty Cycle is set to maximum (independent of vehicle speed) until the system is shifted out of 4L.
c. All Electric Shift activity is halted until the Ignition is cycled. If a shift is in progress it will be completed.
If the Front Speed Sensor recovers continuously for O.5 second the TCCU will function normally. The “4WD
CHECK ” lamp is turned off but the fault code will remain in memory.
4. Rear Speed Sensor Test If a Rear Speed Sensor fault is detected continuously for 0.5 second the “4WD CHECK ” lamp is illuminated. The
TCCU then responds as follows:
a. If the system is in High Range the TCCU uses the Front Speed Sensor to determine the EMC Touch Off level and wheel slip control is suspended.
b. If the system is in Low Range, the EMC Duty Cycle is set to maximum (independent of vehicle speed) until the system is shifted out of 4L.
c. All Electric Shift activity is halted until the Ignition is cycled. If a shift is in progress it will be completed.
If the Rear Speed Sensor recovers continuously for 0.5 second the TCCU will function normally. The “4WD
CHECK ” lamp is turned off but the fault code will remain in memory.
5. Both Speed Sensor Faulty If both the Front and Rear Speed Sensors are faulty continuously for 0.5 seconds the “4WD CHECK ” lamp is
illuminated. The TCCU then responds as follows:
a. If the system is in High Range the TCCU sets the EMC Touch Off level based on a vehicle speed of 0 and wheel slip control is suspended.
b. If the system is in Low Range, the EMC Duty Cycle is set to maximum until the system is shifted out of 4L.
c. All Electric Shift activity is halted until the Ignition is cycled. If a shift is in progress it will be completed.
If both Speed Sensors recover continuously for 0.5 second the TCCU will function normally. The “4WD CHECK ”
lamp is turned off but the fault code will remain in memory.
6. EMC Test The EMC is tested for open circuit or short circuit to ground. If a fault is detected continuously for 0.8 second the “4WD CHECK ” lamp is turned on and all TOD TM
activity is halted.
If the EMC recovers continuously for 0.8 second the TCCU will function normally. The “4WD CHECK ” lamp is
turned off but the fault code will remain in memory.
TRANSFER CASE (TOD) 5D2-19
ClassificationEngine Type
Transmission/Vehicle Type Axle Ratio
Tire Size
Coding Required
1. Replacement of TOD control unit.
2. Adjustment by input error.
3. Change of tire specification.
Items
Gasoline Engine (E32) 661 Diesel Engine
661LA Diesel Turbo Engine
662 Diesel Engine
662LA Diesel Turbo Engine Manual Transmission
Automatic Transmission MUSSO
KORANDO 3.734.554.895.38 5.86
P215 P235P255P275
Coding Method
1. Check and record engine type, axle ratio and tire size.
2. Ignition “OFF ”.
3. Connect SCANNER with diagnosis connector in engine room.
4. Ignition “ON ”.
5. Read the current memorized specification in TOD control unit.
6. Compare memorized specification with the checked record. If not matched, perform a coding.
7. Read again memorized coding specification in TOD control unit for confirmation of coding.
8. Check coding specification whether it matches with vehicle or not. If not, perform a coding again.
Coding items