SsangYong Musso. Manual - part 472

AUTOMATIC TRANSMISSION  5A-65

If the gear lever is incorrectly adjusted, the transmission may shift gears on bumpy road surfaces.

6

Transmission Oil Temperature Sensing Fault

!

All shifts will be firm until the transmission has warmed up, because a high transmission oil temperature is

assumed.

If a fault is undetected, the temperature is likely to be evaluated as being lower than actual, resulting in softer shifts
with ‘end bump’ (very firm feel at the end of the shift).

7

Mode Setting Fault

!

All shifts will occur as if the mode is set to ‘NORMAL’.

!

The mode indicator will always be off indicating that ‘NORMAL’ mode is selected.

!

The mode indicator will not respond to changes in switch setting.

If a fault is undetected, the mode as indicated by the mode indicator is not likely to respond to the mode switch.

8

Battery Voltage Sensing Fault

If the battery voltage is low then shifts to first gear are inhibited.9 the battery voltage is high (>16.5V) then the
transmission goes into limp home (LHM) mode.

If a fault is undetected, the transmission is likely to incorrectly evaluate an ON/OFF solenoid fault resulting in limp
home mode (LHM) operation.

9

ON/OFF Solenoid Fault (Solenoids 1,2,3 and 4)

The transmission adopts its limp home mode (LHM) operation, described above. However, if solenoid 1 is faulty then
the fourth gear LHM strategy will be adopted independent of vehicle speed.

If a fault is undetected, the operation of the transmission is dependent on which solenoid is actually faulty. The
characteristics for different solenoid fault conditions are listed in table 6.1.2.

10 ON/OFF Solenoid Fault (Solenoids 6,7)

If solenoid 6 is found faulty it is always disabled resulting in high line pressure being applied continuously.

If solenoid 7 is found faulty it is disabled resulting in the transmission being locked always.

The transmission does not go into LHM.

11 Variable Pressure Solenoid Fault

The transmission adopts its LHM operation.

If a fault is undetected, the transmission shift feel is likely to be poor for all shifts.

12 Software Fault

The transmission adopts the third gear LHM strategy of operation, independent of vehicle speed. The operation of
the TCU under this condition is difficult to predict. Its operation may be erratic.

If a fault is undetected, the operation of the TCU is likely to be erratic.

13 Power Supply Fault

The transmission adopts the third gear LHM strategy of operation, independent of vehicle speed. If there is an
intermittent power supply connection, the TCU will power-up in fourth gear and then shift to the appropriate gear to
satisfy the conditions present. The power supply is not monitored for fault evaluation.

All faults except for solenoid faults can be recovered without having to turn the TCU off and back on. However, in
general the recovery requires that no faults are present for a period of time (approx. 3 or 30 seconds). Recovery from
a fault will not clear the fault from the keep alive memory

14 Transmission Sump Temperature Exceeding 135°C

!

The converter lockup clutch will be applied at lower speeds, causing a shudder through the vehicle.

!

The mode indicator will flash in some vehicles.

These faults can be due to the transmission oil overheating or due to an incorrect signal received from the temperature
sensor.

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 the

vehicle 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 OFF

Always ON

Solenoid

1

2

3

4

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 operating

voltage 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 the

ignition 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 Input

Fault

Throttle Input Fault

Temperature Input Fault

Shift Lever Position

Input Fault

(Inhibitor/PRNDL Switch)

Engine Speed Sensor

Fault

Shaft Speed Sensor

Fault

(Speedo Sensor)

Solenoid

1

2

3

4

5

6

7

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 the

wiring.

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 a

loose 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 acceptable

limits 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 the

solenoid 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 acceptable

limits 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 normal

operating 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 Pressure

Solenoid)

Throttle Not Learnt

Solenoid

9

10

11

12

13