2003 SSANGYONG MUSSO automatic transmission

5A-66 AUTOMATIC TRANSMISSION
Diagnostic Trouble Messages The diagnostic trouble messages generated by the TCU and their possible causes are listed in table 6.1.3.
Table 6.1.2 - Transmission Operations for On/Off Solenoid Faults
Transmission Operation
First gear instead of second and fourth gear instead of third. This results in a 1
4 shift as the vehicle accelerates from rest.
Second gear instead of first and third gear instead of fourth.This results in second gear starts.
Fourth gear instead of first and third gear instead of second.This results in fourth gear starts.
Second gear instead of third and first gear instead of fourth. This results in a 1
2 then 2
1 (overrun) downshift as the vehicle
accelerates from rest. The following shifts become poor:1
3, 1
4, 2
1 2
3, 2
4, 4
2, 4
1.
The following shifts become poor: 3
4, 4
3, 3
2.
There may be slippage in the gears during torque converter locking. The following shifts become poor:1
2, 1
3, 1
4, 2
3, 2
4, 3
1, 3
2 (All Including Manual), 3
4,
4
1,4
3.
The following shifts become poor:2
4, 3
2.
There may be slippage in the gears during torque converter locking.Line pressure always high.Line pressure always low thus resulting in risk of slippage in gears.
Torque converter always unlocked.
Torque converter always locked in 3rd and 4th gears, causing thevehicle to shudder at lower speeds,
Condition
Always ON Always OFF Always OFF Always ON Always OFF Always ON Always OFF Always ON Always OFF Always ON Always OFFAlways ONSolenoid 1 2 34 6 7

AUTOMATIC TRANSMISSION 5A-67
Table 6.1.3 - Diagnostic Trouble Messages
Description / Cause
There have been no faults recorded since the TCU was last cleared. If
the fault history has never been cleared, then there have been no
faults recorded since the TCU was originally powered up.There is an internal fault within the TCU.
The voltage measured by the TCU corresponding to the battery sup-
ply voltage has been outside the range of the maximum operatingvoltage of 16.5 volts.
The minimum operating voltage depends on the transmission tem-
perature but is typically between 8-9 V for a warm transmission.
The voltage measured by the TCU from the throttle potentiometer has been outside acceptable levels.
This would typically indicate a loose connection in the wiring to, or
within, the throttle sensor which has caused the signal at the TCU to
read 0V or 5V.
The voltage measured by the TCU across the temperature Input ter-
minals has been outside acceptable levels.
This would typically be caused by a loose connection or short to ground
in the wiring to, or within, the temperature sensor which has caused
the signal at the TCU to read 0V or 5V. The voltage measured by the TCU across the shift lever input termi- nals has been outside acceptable levels for a significant length of
time. This would typically be caused by a loose connection or short to
ground in the wiring to, or within, the inhibitor switch which has caused
the signal at the TCU to read 0V or 5V.
The signal from the ignition, of ignition pulses, has either been non- existent or has been unreliable.
There are two reasons this fault could occur. The first is due to a lack
of ignition pulses when other TCU inputs would indicate that the en-
gine is running, that is the gear lever is in a driving position, the throttle is applied and vehicle speed increasing. The second cause of this (aunt is the frequency of the pulses of theignition pulse input to the TCU indicate an unachievable engine speed.
The pulses from the shaft speed sensor have either been non-exis-tent or have been unreliable.
There are three reasons this fault could occur. The first is due to a sudden loss of speedometer pulses at a time when they were fre quent,thus indicating an unachievable degree of deceleration of the drive
line. The second cause of this fault is that the frequency of the pulses
on the shaft speed sensor input to the TCU indicate an unachievable
propeller shaft speed. The third is the presence of a high engine speed
in a driving gear with no speedometer pulses.
Condition
Test Pass
Transmission Control Module Fault
Battery Voltage InputFault Throttle Input Fault
Temperature Input FaultShift Lever Position Input Fault(Inhibitor/PRNDL Switch) Engine Speed Sensor Fault Shaft Speed Sensor Fault(Speedo Sensor)Solenoid 1 2 3 4567 8

5A-68 AUTOMATIC TRANSMISSION
Description / Cause
The signal from the mode switch is unreliable.
This fault is caused by too many changes in the mode input signal
over a period of time. Typical causes would be an intermittent connec
tion in the switch or wiring or an intermittent short to ground in thewiring.
The data link between the TCU and the engine management module
is found to be unreliable because the checksum, or the data received, did not match the correct checksum.
This could be caused by an open circuit, short circuit to ground or aloose connection in the link wire itself.
Each solenoid in turn is switched off if it was energised, or switched on
if it was not energised by a very small 100 ms pulse. This pulse is too
short for the solenoid to react so transmission operation is not af fected.
The solenoid feedback voltage is measured before the 100 ms pulse
and again during the pulse. If the difference is outside the acceptablelimits the relevant fault messages are set.
Typical causes would be an open circuit in the wiring to or within the
solenoid, or a short circuit to ground in the wiring to, from or within thesolenoid in question.If several of these fault codes are presents check the wiring or
connectors that are common to the selected solenoids, especially the earth connections.
The state of the solenoid feedback voltage is outside acceptablelimits but the faulty solenoid could not be isolated.The current to solenoid 5 was outside acceptable limits.
This fault results from a mismatch between the current set point for
solenoid 5 and the current measured by the feedback within the TCU.
Typical causes would be an open circuit or short circuit to ground in
the wiring to, from or within the solenoid. It is also possible that there
has been a fault in the solenoid output circuit. If this is the case
however, the fault should be continually present.
The closed throttle position has not been learnt. This fault may be caused by the transmission not having reached normaloperating temperature or the engine idle speed being incorrect.The TCU will learn the closed throttle position automatically when the transmission is brought to normal operating temperature and the engine is allowed to idle in Drive with the‘ base idle ’ correctly set and the air conditioner (if fitted)
switched off.
Condition
Mode Switch Input Fault(Power/Economy Mode) Data Output Link Fault On/off Solenoid Fault (Solenoid 1,2,3,4,6,7) Solenoid 5 Fault
(Variable Pre ssure
Solenoid) Throttle Not LearntSolenoid
9
10 11 12 13

AUTOMATIC TRANSMISSION 5A-69
MECHANICAL TESTS
In Vehicle Transmission Checks
Carry out the following tests before removing the transmission. See Checking Transmission Fluid Level, Section 7.2.1.
Check that the transmission oil is not burnt (colour and smell are correct).
Ensure that the transmission is not in limp home mode (LHM).
Check that the battery terminals and the earth connections are not corroded or loose.
Check the engine stall speed is within the handbook value.
Check that the cooler flow is not restricted.
Check that all electrical plug connections are tight.
Carry out a road test to confirm the symptoms, if necessary.
Inspect the oil, ensure that there are no metal or other contaminants in the oil pan.
Diagnosing Oil Leaks
Determine the source of oil leaks by firstly cleaning down the affected area, then driving the vehicle. Inspect the seals to confirm the source of the leak. To determine the source of a rear servo oil leak, raise the vehicle on a hoist, then carry out a reverse stall.
To determine the source of a front servo leak, raise the vehicle on a hoist, then run the vehicle in second gear.
Troubleshooting Charts The troubleshooting charts are set out as follows: Table 6.2.1 Drive Faults,
Table 6.2.2 Faulty Shift Patterns.
Table 6.2.3 Shift Quality Faults.
Table 6.2.4 After Teardown Faults.
Table 6.2.1 - Drive Faults
Action
Check the fluid level. Top up as necessary. Inspect and clean C1/C2 feed. Reinstall/renew the ‘z’ link.
Remove, clean and re-install the PRV.
Inspect and replace as necessary.
Inspect and replace as necessary.
Inspect and replace as necessary.
Check servo adjustment or replace rear band
as necessary.
Check for failure in C3, C3 hub or C1/C2 cylin-
der. Repair as necessary.
Inspect and clean PRV.
Inspect and replace pump gears as necessary.
Inspect and repair as necessary.
Possible Cause
Insufficient auto transmission fluid.
Blocked feed in C1/C2 cylinder.
‘Z’ link displaced.
Primal regulator valve (PRV) jammed open.Overdrive shaft or input shaft seal ringsfailed. 3-4 or 1-2 one way clutch (OWC) installed backwards or failed.C2 piston broken or cracked.
Rear band or servo faulty.
Failure in C3, C3 hub or C1/C2 cylinder.Jammed primary regulator valve (PRV). Damaged/broken pump gears. Dislodged output shaft snap ring.Symptom
No Drive in D No Drive in ReverseNo engine braking
in Manual 1 Engine braking in Manual 1 is OKNo drive in Driveand Reverse

5A-70 AUTOMATIC TRANSMISSION
Action
Inspect S1. Repair or replace as necessary.
Check for 12 Volts applied to S1 at all times orfor wiring fault.
Inspect S1. Repair or replace as necessary.
Check for 12 Volts applied to S1 at all times or for wiring fault.
Inspect S2. Repair or replace as necessary.
Check for open circuit or wiring fault.
Inspect S2. Repair or replace as necessary. Check for open circuit or wiring fault.
Inspect and adjust as necessary.
Inspect and repair as necessary.
Inspect and replace or refit as necessary. Inspect ‘O’ ring. Refit or replace as nec essary.
Inspect the 2-3 shift valve. Repair or replace
as necessary.
Inspect C1 clutch. Repair or replace as neces-
sary.
Inspect ball. Refit or replace as necessary. Inspect C4. Repair C4 or replace C4 wave plate
as necessary.
Inspect rear band adjustment. Adjust as nec-
essary.
Inspect ball- Refit or replace as necessary. Inspect ’0’ring. Refit or replace as necessary.
Inspect C4 and C4 wave plate. Repair or re-
place as necessary.Inspect inhibitor switch. Repair or replace as necessary.
Inspect the 1-2 shift valve.
Repair or replace as necessaryInspect inhibitor switch.Repair or replace as necessary.
Inspect the 2-3 shift valve.Repair or replace as necessary.
Possible Cause
S1 always OFF. S1 always ON.
S2 always OFF. S2 always ON. B1 failed. Loose band adjustment.Front servo piston or seal failed.S1/S2 ball misplaced, Smaller ’0’ring on front servo piston failed
or missing. 2-3 shift valve jammed.C1 clutch failed or slipping in 3rd and 4th.(Gives 1st in 3rd and 2nd in 4th.) Over-run clutch (OC)/low ball misplaced. C4 failed or C4 wave plate broken. Rear band slipping when hot. Reverse/Low-1st ball misplaced. Rear servo inner ‘O’ ring missing.
C4 failed or C4 wave plate broken.
Inhibitor switch faulty. 1-2 shift valve jammed.
Inhibitor switch fault, 1-2 only. 2-3 shift valve jammed.Symptom
2-3 shift only
(no 4th or 1st)
1-4 shift only1-3-4 (Delayed1-2shift)4-3 shift only 1-2-Neutral
(1st over run)1-3 shift only 1-3-4 only 1-2-1 only No manual 4-3,3-2
or 2 - 1 No manual 1st 1st gear only or
2nd,3rd, and 4thonly 1st and 2nd only or 1st, 3rd and 4th
only

AUTOMATIC TRANSMISSION 5A-71
Table 6.2.2 - Faulty Shift Patterns
Action
Inspect inhibitor switch. Repair or replace as
necessary.
Inspect the 3-4 shift valve. Repair or replace
as necessary.
Inspect the release valve. Repair or replace as
necessary.
Inspect S3 or S2. Repair or replace as neces-
sary.
Inspect the regulator valve. Repair or replace
as necessary.
Inspect the ball. Refit or replace as necessary.
Inspect the sealing rings. Refit or replace as
necessary.Inspect the ‘O’ rings. Refit or replace as neces-
sary.
Inspect the bleed ball. Refit or replace as nec-
essary.
Inspect S1 or S4. Repair or replace as neces-
sary.
Inspect the release valve. Repair or replace as
necessary.
Inspect the band. Adjust as necessary. Inspect the ‘O’ rings. Refit or replace as neces-
sary.
Inspect S5. Repair or replace as necessary.
Inspect the regulator valve. Repair or replace
as necessary.
Possible Cause
Inhibitor switch fault, 1-2-3 only. 3-4 shift valve jammed. Jammed band 1 release valve. Faulty S3 or S2 solenoid. Faulty clutch apply regulator valve.Missing or damaged clutch apply feed ball. Damaged input shaft sealing rings. Damaged C1 piston ‘O’ rings.
Damaged or dislodged C1 piston bleed ball. Faulty S1 or S4 solenoid.
Jammed band 1 release valve. Incorrect front band adjustment. Damaged front servo piston ‘O’ rings.
Faulty or damaged variable pressuresolenoid (S5). Faulty band apply regulator valve.Symptom
1st,2nd and 4th
only or 1st,2nd,
and 3rd (tied up in3rd) Harsh 2-3 shift Harsh 3-4 shift

5A-72 AUTOMATIC TRANSMISSION
Action
Drain and fill with specified ATF.
Check that S5 is fitted correctly, or replace S5.
Inspect band apply and clutch apply regulator
springs. Refit or replace as necessary.
Inspect the ball. Refit or replace as necessary.
Inspect C4 clutch. Replace or repair as neces-
sary.
Check the alignment. ]Realign as necessary.
Inspect wave plate. Replace as necessary.
Inspect S5 and replace as necessary.
Inspect the damper spring and replace as nec-
essary.
Replace spring as necessary.
Check the clearance and adjust as necessary.
Inspect C4. Repair or replace as necessary.
Inspect piston. Repair or replace as necessary.
Inspect and adjust band as necessary. Replace the plug. Replace the spring.Replace the spring/plug.Refit the ball.
Inspect the clutch. Repair the clutch as neces-
sary. Inspect and clean C1 feed.Replace the piston.
Inspect and replace the sealing rings and/or
shaft as necessary. Inspect and replace the ball.
Inspect and replace the sealing rings and/or
shaft as necessary.
Inspect and repair the C1 clutch as necessary.Refit the valve. Replace the ball.
Possible Cause
Incorrect auto transmission fluid (ATF).
S5 faulty won, or incorrectly fitted.Band apply and clutch apply regulatorsprings misplaced. Over-run clutch (OC)/Low-1st ball misplaced.C4 clutch worn or burnt. C4 wave plate not lined up with the holes in the piston. C4 wave plate failed.S5 worn.S5 damper spring broken. Front servo belleville spring broken. Incorrect C4 pack clearance.Damaged C4 clutch.Cracked C2 piston (leaking into C4).Incorrect band adjustment Front servo plastic plug missing B1R spring broken.B1R spring/plug left out.C1/B1R ball misplaced.C1 clutch damaged. Restriction in C1 feed. C1 piston check ball jammed.
Overdrive or input shaft sealing rings dam-aged. C1/B1R ball misplaced.
Overdrive or input shaft sealing rings dam-aged.C1 clutch damaged.4-3 sequence valve in backwards. Low-1st check ball misplaced.Symptom
All Shifts Firm Manual 4-3-2-1 is soft delayed or
missing Firm 1-2 Hot
4th Tied up
Tied up on 2-3Flare on 2-3 Slips in 4th Flare on 4-3, Flare on 3-2Firm Manual low
shift-high line press.

AUTOMATIC TRANSMISSION 5A-73
Table 6.2.3 - Shift Quality Faults
Action
Check the resistance. Replace the inhibitor
switch as necessary.
Inspect and replace the sensor as necessary.
Inspect and adjust the band as necessary.Inspect and replace the ’0’rings as necessary.
Inspect, repair or replace S5 as necessary.
Inspect, repair or replace S1 or S4 as neces-
sary.
Inspect, repair or replace the BAR as neces-
sary.
Inspect and repair as necessary.
Inspect and clean CCCV.
Inspect, repair or replace as necessary.
Possible Cause
Faulty inhibitor switch.
Faulty throttle position sensor. Incorrect front band adjustment.Damaged front servo piston ’0’rings.
Faulty or damaged variable pressure so- lenoid (S5). Faulty S1 or S4 solenoid. Faulty band apply regulator valve (BAR). Misassembled front servo return spring. Jammed converter clutch control valve(CCCV).Faulty solenoid 7.Symptom
Harsh 1-2 shift stalls when Drive
or Reverse selected Shudder
on Rolldown