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Daewoo Korando. Manual - part 256

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

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

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.

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 rings

failed.

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

Reverse

No engine braking

in Manual 1

Engine braking in

Manual 1 is OK

No drive in Drive

and Reverse

5A-70 AUTOMATIC TRANSMISSION

Action

Inspect S1. Repair or replace as necessary.

Check for 12 Volts applied to S1 at all times or

for 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 necessary.

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 necessary

Inspect 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 only

1-3-4 (Delayed

1-2shift)

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 4th

only

1st and 2nd only

or 1st, 3rd and 4th

only

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