2006 GREAT WALL HOVER Service Repair Manual

Automatic transmission-45
Diagnosis and test
Test system
1. Recommended test equipment and program
The test equipment and control unit for design will be used for the test of all vehicles. The parts for transmission test includes:
Tester for service after sales
Special vehicle for test
2. Tester for service after sales
After the special programming, the tester equipped with special car test software can be used to test the specified system and unit.
The program allows the normal communication between the transmission control units (TCUs) .
The computer needs the required information from the customer and select the necessary data through the manual. For example:
view the code, clear the error code and make the real-time operation. For detailed operating instruction refer to user’s manual.
The equipment can be used by the trained specialized persons, such as technician, machinist to test the electronic and loop
problem related to transmission. The testable information includes: the engine speed, rode (shaft speed), transmission fluid
temperature, position of throttle position, status of solenoid valve and gear and position of operating lever. Additionally, it can be
used to detect the current and stored problem.
3. Description of TCU pin
The description of TCU pin code had been listed in Table 6.1.1
For description of wire bunch refer to Figure 6.1.1
Pin No. Function Type 2WD description
A14 Public grounding GND
● Negative pole of TCU supply, connected to negative pole of
battery.
A13 Nonuse
－－
○ －－－－－
A12 M ode indicator la mp
Snowland mode OP
● Indicate that select the “Snowland M ode” operating method.
A11 Parking-Gear indicator lamp O P
● T he drive instrum ent panel indicator la mp indicates tha t is in
the “Parking G ear”
A10 Reverse-Gear indicator lamp OP
● T he drive instrum ent panel indicator la mp indicates tha t is in
“ Revers e G ear”
A9 N-G ear indicator lamp O P
● T he drive instrum ent panel indicator la mp indicates tha t is in
“Idle N Gear”
A8 Nonuse －－ ○ －－－－－
A7 Nonuse －－ ○ －－－－－
A6 M ode indicator la mp
dynamic mode OP
● Indicate that select the “ dyna m ic mode” operating method.
A5 Nonuse ―― ○ －－－――
A4 Nonuse ―― ○ －－－－－
A3 Nonuse ―― ○ －－－－－
A2 Mode switch IP
● The switch is used to select the “economic mode”, “dynamic
m ode” and “ snowla nd mode”. T he voltage is varia ble in
range of 0 V－2V .
A1 Nonuse ―― ○ －－－－－
A30 Power supply PWR
● Power supply for TCU; is the main power source of drive
unit and solenoid valve.
A29 Nonuse ―― ○ －－－－－
A28 1st-G ear indicator lamp
/1st-G ear position﹡ OP
● Drive the instrument panel indicator lamp indication, indicate
that the gear-position is in “1st-G ear”
A27 2nd-G ear indicator lamp
/2nd-G ear position OP
● Drive the instrument panel indicator lamp indication, indicate
that the gear-position is in “2nd-G ear”
A26 3rd-G ear indicator lamp
/3rd-Gear position﹡ OP
● Drive the instrument panel indicator lamp indication, indicate
that the gear-position is in “3rd-Gear”
A25 Automatic gear indicator
lamp /4th –Gear position OP
● Drive the instrument panel indicator lamp indication, indicate
that the gear-position is in “automatic-Gear”

Automatic transmission-46
Pin
No. Type 2W D Description
A24 CAN (-ve) I/O ○ CAN hidden communication end
A23 CAN (+ve) I/O ○ CAN exposed communication end
A22 K line communication
connection I/O ● Diagnosis information and car code
A21 Nonuse ―― ○ －－－－－
A20 Nonuse ―― ○ －－－－－
A19 Shaft speed sensor
signal IP ○ The sensor sends the shaft speed signal to T CU
A18 Nonuse ―― ○ －－－－－
A17 Nonuse ―― ○ －－－－－
A16 Nonuse ―― ○ －－－－－
A15 Nonuse ―― ○ －－－－－
B6 Gear-position IP ● T h e sw itch ha s th e variab le-vo ltage ; in dicate the
gear-position steering colum n selected (PRND321). The
vo ltage is variab le in the ran ge o f 0 V --5 V .
B5 transm ission fluid
temperature IP ● The sensor indicates the transmission fluid temperature.
High R=Low temperature
Low R= High temperature
The voltage is variable in the range of 0V to 5V
B 4 so leno id va lve 4 O P ● N /O FF no rm al-op ened so leno id valve , co m b ined w ith the
O N /O FF w itch o f so len oid valve 3; en sure the sh ifting
quality and sequence
B 3 so leno id va lve 1 O P ● ON/OFF normal-opened solenoid valve; combined with
o the r so leno id va lve; u sed to determ ine the selected
gear-position.
B2 Nonuse ―― ○ －－－－－
B1 R e tu rn so len oid va lve
5 IP ● Using for grounding of VPS and current of circuit can be
detected, then process the feedback control for the VPS.
B14 Gear-position －
grounding GND ● PRND321 Gear-position switch grounding
B13 transm ission fluid
temperature －
grounding GND ● Connected to grounding pin of temperature sensor.
B12 solenoid valve 6 OP ● ON/OFF normal-opened solenoid valve, determine the
high or low of line pressure
B11 solenoid valve 2 OP ● O N /O FF norm al-o pened so leno id va lve, co m bined w ith
o the r so leno id valves; u sed to d eterm ine the selected
gear-position.
B10 solenoid valve 3 OP ● O N /O FF norm al-o pened so leno id va lve, co m bined w ith
the O N /O FF sw itch of solenoid valve 4; ensure the
shifting quality and sequence
B 9 so leno id va lve 7 O P ● ON/OFF normal-opened solenoid valve, hydraulic torque
converter locking; increase the efficiency of medium
speed run.
B8 Nonuse ―― ○ －－－－－
B 7 so leno id va lve 5 (+ ve) O P ● It is the so leno id va lve w hich can ch an ge th e p ressu re
d urin g the sh iftin g a nd on /o ff o f so leno id valve .
●= connected line ○= unconnected line ＊=only
OP= output IP=input I/O=input/output
GND=grounding REF=reference PWR=power
Table 6.1.1 Description of TCU pin

Automatic transmission-47
4. Operating mode of transmission
TCU realizes the effective control for the transmission according to the accurate information acquired form the input data and
complete control for the output data. To ensure the input and output of TCU is actual and effective, TCU executes the data sense
command for hardware and software. For the failure information found in the following operating mode described in detail, TCU
will give the corresponding response.
Similarly, it exists the possibility that could not find out the failure cause. If encounter the condition, the operation for transmis
sion is determined difficultly.
Following condition will effect the operation of transmission, but will not appear the detection failure information.
a. Power supply failure
The transmission adopts the 3-Gear lame Home Mode (LHM) irrelevant to car speed.
If occur the intermittent power supply, then TCU will start form 4-Gear and is switched to the proper gear to meet the
requirement of current work. At this time, it will not monitor the power supply status.
b. The transmission fluid temperature is higher than 135
If found the transmission temperature is high:

The torque converter lock clutch will start in low speed and the car will have the vibration.

Some cars will have the condition that the mode indicator lamp is flash.
The reason for the condition may be the transmission fluid temperature is high or acquire the inaccurate single form the
temperature sensor. If occurs the temperature failure, it may find the high temperature operating condition.
c. Failure of ON/OFF solenoid valve
If one of the solenoid valves has the mechanical failure, TCU will not find the failure. At this time, the failure operation of
transmission will be determined according to the solenoid valve with failure. The characteristic of different solenoid valve failure
is listed in Table 6.1.2.
reverse pin
gear indication pin
Gear sensor(black)
Figure 6.1.1 Description for wire bundle pin

Automatic transmission-48
s oleno id
valve Condition Transmission operation
1 Opened
always 1st-Gear replaces 2nd-Gear; 4th-Gear replaces 3rd-Gear. It causes the car form the G ear shift of 1
→1→4→4 when accelerate form static. The transmission stay longer time in Gear; worse 1→4
shift feeling.
Closed always 2nd-Gear replaces 1st-Gear; 3rd-Gear replaces 4th-Gear. It causes the car form the G ear shift of 2
→2→3→3 when accelerate form static. It is said that starts form 2nd-Gear.
2 Closed always 4th-Gear replaces 1st-Gear; 3rd-Gear replaces 2nd-Gear. It causes the car form the G ear shift of 2
→2→3→3 when accelerate form static. That is saying that start form 4th-Gear.
Opened
always 2nd-Gear replaces 3rd-Gear; 1st-Gear replace 4th-Gear.
It cause the car is shifted form 1st-Gear to 2nd-Gear, then from 2nd-G ear to Gear when accelerate
form static. It will feel the transmission is in free gear position after 2→1 Gear shift.
1&2 Opened
always Can not realize the reverse gear; only has 1st-Gear operation.
3 Closed always Following shifts are bad. (2→3 is worst ):1→3, 1→4, 2→3, 2→4, 4→2, 4→1
Opened
always Following gear shifts are worse: 3→4, 4→3, 3→2。
It may cause the gear slide when the hydraulic torque converter is locked.
4 Closed always Following gear shifts are worse:
1→2, 1→3, 1→4, 2→3, 2→4, 3→1, 3→2, (including manual) 3→4, 4→1, 4→3
Opened
always Following gear shifts are worse: (1→2 is worst) 2→4, 3→2 It may cause the gear slide when
the hydraulic torque converter is locked.
6 Closed always The line pressure is high always.
Opened
always The line pressure is low always. So it cause the slide between gears. The clutch C1 and brake belt
B1 will be burned.
7 Closed always The hydraulic torque converter is without lock.
Opened
always The hydraulic torque converter is locked in 3rd-Gear and 4th-Gear. It cause the car generates the
vibration in low-speed status.
Table 6.1.2 Operation of transmission when ON/OFF solenoid valve is faulty
Mechanical detection
1.Inspection of transmission on car
It should process the following detections before disassemble the transmission:
process the on-road drive test to determine the failure cause .(according to requirement)
Detect the standard of transmission fluid. (refer to 7.2.1)
Ensure the transmission fluid in not overheated. (Normal color and smell)
Detect the failure information.
Check the battery terminal and grounding for corrosion or loose.
The engine speed is within the specified value in manual.
Check the cooling system for normal operation.
All power supply and plug wires is tight and not loose.
Check the transmission fluid, ensure the oil pan is without other martial material or pollutant.
2. Oil leakage detection
It should wash the polluted part of the transmission before select the oil leakage part, then drive the car.
When detect the leakage part of the rear servo system, it should lift the car by lifter firstly, then switch the gear to reverse
gear within 10s.
When detect the leakage part of front servo system, it should lift the car by lifter firstly, then switch the gear to gear-2
(winter mode).
The time switched to 2nd-Gear should be no more than 10s to avoid the oil in the torque converter is overheated.
3. FAQ table

Automatic transmission-49
The distribution of FAQ table is shown as follows:
Table 6.2.1 Drive failure Table 6.2.3 Shift quality failure
Table 6.2.2 Shift mode failure Table 6.2.4 Disassembly failure
failure Possible reason Corresponding measure
“D”-Gear operation
has not drive The automatic transmission fluid is insufficient.
The oil-entering of C1/C2 piston is blocked.
The “Z” is assembled incorrectly.
The primary regulating valve plug is opened.
The overspeed shaft or input shaft sealing ring is
failure.
3→4, 1→2 single-way clut ch is installed in revers e or
failure. Check the liquid level. Fill it up if necessary.
Check and wash the C1/C2 oil inlet device.
Reinstall the “Z” connection.
Remove, wash and reinstall the primary
regulating valve.
Check and replace it if necessary.
Check and replace it if necessary.
The reverse shifting
operation is without
drive.
The manual 1
st-Gear
has not engine
brake.
The engine brake is
normal in manual
1
st-Gear. The input shaft oil seal ring is damaged.
The rear brake belt or servo system is faulty.
C3, C3 wheel shaft or C1/C2 cylinder are out of work. Check and replace it if necessary.
Test the servo system or replace the rear brake
belt according to the requirement.
Test the failure C3, C3 wheel axle or C1/C2
cylinder.
Repair it in time if necessary.
“D” –Gear and reverse
–Gear operation is
without drive. The primary regulating valve is blocked.
The pump gear is damaged.
Take out the output shaft clasp. Det ect and clean the primary regulating valve.
Check and replace the pump gear if necessary.
Check and repair it if necessary.
Only can 2→3 shifting
(can not realize the
4
th-Gear and 1st-Gear) S1 is closed always. Test the S1. Repair or replace it if necessary.
Test the failure of S1 12V power supply
voltage or wire bundle.
Only can 1→4 shifting
1→3→4 shifting (1
→2 shifting delay). S1 is opened always Test the S1. Repair or replace it if necessary.
Test the failure of S1 12V power supply
voltage or wire bundle.
Only can 4→3 shifting S2 is closed always.
Test the S2. Repair or replace it if necessary.
Test the failure of circuit break or wire bundle.
1→2→neutral position
shifting (1st-Gear
transition) S2 is opened always Test the S2. Repair or replace it if necessary.
Test the failure of circuit break or wire bundle.
Only can 1→3 shifting B1 is out of work
The brake belt is loose.
The front servo piston or oil s eal is out of work.
S1/S2 ball spool is reinstalled in wrong place. Test and adjust it according to the requirement.
Test and maintain it according to the
requirement. Test and replace or reinstall it according
to the requirement.

Only can 1→3→4
shifting The small O-ring of front s ervo piston is invalid or
lost.
2→3 Gear position shifting valve is blocked. Det ect the O-ring. Process the replacement or
reinstallation if necessary. Detect the 2→3
Gear shifting valve; Process the maintenance
or replacement according to the requirement.
Only can 1→2→1
shifting C1 is invalid or 3rd-Gear and 4th-Gear is loose. (give
to 1st-Gear in 3rd-gear; give to 2nd-Gear in 4th-Gear) Det ect the clutch C1. Repair or replace it if
necessary.
Can not realize the
man ual 4→3, 3→2, 2
→1 Overspeed clutch /ball spool has displacement.
C4 is invalid. Detect the ball spool. Process the replacement
or reinstallation according to the requirement.
Det ect the C4. Repair C4 or r eplace the C4
wave pan according to the necessary.

Automatic transmission-50
Only can 1→3→4
shifting The sm all O -ring of front servo piston is invalid or lost.
2→3 G ear psition shifting valve is blocked. D etect the O -ring. P rocess the replacem ent or
reinstallatio n if n ecessary. D etect th e 2→3
G ear shifting valve; Process the maintenance
or replacem ent according to the requirem ent.
Only can 1→2→1
shifting C1 is invalid or 3rd-G ear and 4th- G ea r is lo o s e . (g iv e t o
1st-G ear in 3rd-gear; give to 2nd-G ear in 4th-G ear) D etect th e clutch C 1 . R ep air or rep la ce it if
necessary.
Can not realize the
manual 4→3, 3→2, 2
→1 O verspeed clutch /ball spool has displacem ent.
C4 is invalid. D etect the ball spool. Process the replacem ent
or reinstallation according to the req uirem ent.
D etect the C4. R epair C4 or replace the C 4
wave pan according to the necessary.
W itho ut m an ual
1st-G ear The rear brake belt is loose when the tem perature is
high.
The R -G ear/Low speed 1
st-G ear ball spool has
displacem ent.
The internal “O ” –ring of rear servo is lost.
C4 is invalid. D etect the rear brake b elt, adjust id necessary.
D et e ct t h e b a ll sp o o l, R ein s ta ll o r r ep la c e it if
necessary.
D etect the O -ring, R einstall or replace it if
necessary.
D et e ct th e C 4 . R ep a ir o r r ep la c e it if n e c ess a r y.
Only can 1→2→2→4
gear. The dim ension of socket of front servo is large. H as the
possibility of loose of plug.
It has the trend that ca n n ot realize th e reverse-G ear if
drive the vehicle in this condition continuously. Repair or replace it if necessary.
Detect the C3 piston O -ring, replace it if
necessary.
Only an 1st-gear,
2nd-G ear, 4th-G ear or
1st-G ear, 2nd-G ear an d
3rd-G ear.(3rd-G ear is
tightened) The gear sensor has failure, only can1→2→3 shifting.
3→4 Gear shifting valve is blocked. D etect the gear-position sensor. R epair or
replace it if necessary. D etect the 3→4 gear
shiftin g va lv e. R ep air or r ep la ce it if
necessary.

Automatic transmission-51
Table 6.2.3Shifting quality failure
Bad 1→2 Gear
shifting quality The throttle position sensor has failure.
T he brake b elt is adjusted incorrectly.
The front servo piston O-ring is damaged.
The variable pressure solenoid valve (S5) is damaged or
has failure.
S1, S4 has the failure.
The brake belt combination regulating valve (BAR) has
the failur e.
The front servo release spring is installed incorrectly. Detect the resistance, replace the sensor if
necessary.
Detect and replace the rake belt if necessary.
Detect and r epla ce the O -ring if necessary.
Detect, repair or repla ce the S5 if necessary.
Detect, repair or repla ce the S1, S4 if
necessary.
Detect, repair or repla ce the B AR if
necessary.
Detect and repair it if necessary.
Bad 2→3 Gear
shifting quality B1brake belt release valve is blocked.
S3, S2 has the failure.
The clutch combination regulating valve has failure.
The clutch combination oil feed ball spool is lost or
damaged.
The input shaft oil seal is damaged.
C1 piston O-ring is damaged.
C1 piston oil feed ball spool is damaged. Detect the blow-off valve. Replace or
maintain it if necessary.
Detect the S3, S2.Replace or maintain it if
necessary.
Detect the r egulating valve. R eplace or
maintain it if necessary.
Detect the ball spool .Reinstall or replace it if
necessary.
Detect the sealing ring. Reinstall or replace it
if necessary.
Detect the O -ring .R einstall or replace it if
necessary.
Detect the ball spool .Reinstall or replace it if
necessary.
Bad 3→4 Gear
shifting quality S1, S4 has failure.
B1brake belt release valve is blocked.
T he brake b elt is adjusted incorrectly.
The front servo piston O-ring is damaged.
The variable pressure solenoid valve (S5) is damaged or
has failure.
The brake belt combination regulating valve has failure. Detect the S1, S4.R einstall or replace it if
necessary.
Detect the blow-off valve. Replace or repair
it if necessary.
Detect the brake belt. Adjust it if necessary.
Detect the O -ring .R eplace or maintain it if
necessary.
Detect the S5.R epla ce or maintain it if
necessary.
Detect the r egulating valve. R eplace or
maintain it if necessary.
The engine has
the
extinguishing
co nd itio n
when select
the automatic
gear or R-gear. The torque converter clutch control valve is blocked or
solenoid valve 7 has failure. Detect and clean the torque converter clutch
valve (CCCV)
Has unstable
vibration
co nd itio n. S7 has the failure. Process the necessary detection, maintenance
and replacement according to the
requirem ent.

Automatic transmission-52
Failure Reason Corresponding measures
C2 is burnt.
T operation lever linkage is beyond the
normal adjusting scope.

S6 is invalid.-Operating lever is hard.

The over speed Gear/output shaft sealing
ring is damaged. Monitor and repair the C2 if necessary and
adjust the linkage device.
Repair the C2; detect, repair or replace the
S6 if necessary.
Repair the C2; detect and replace the
sealing ring or shaft if necessary.
C4 is burnt. The clutch C4 assembly clearance is
incorrect.

The over speed Gear/output shaft sealing
ring is damaged.
3→4 one-way clutch is in rear position.

The over speed clutch (OC) /1
st-Gear low
speed ball spool has displacement. Detect the C4. Det ect and adjust the clutch
C4 assembly clearance if necessary.
Repair the C4; detect and replace the oil
seal or shaft.
Repair the C4, detect or modify the OWC
if necessary.
Repair the C4, detect or modify the ball
spool if necessary.
B1 is burnt. B1R spring is damaged.

The dimension of oil inlet hole of front
servo is large and has the possibility of
loose.
The input shaft sealing ring is damaged.
C1/B1R ball spool has displacement. Detect and repair the or replace the spring
if necessary.
Replace the socket if necessary and detect
the C3 piston O-ring.
Replace the sealing ring.
Repair the B1; modify the ball spool if
necessary.
C1 is burnt. B1Rspring / plug is lost.

The over speed Gear/input shaft sealing
ring is damaged

4→3 sequence valve is in rear position.

Clutch attachment oil feed inlet (CAF).
B1Rball spool is lost. Detect and repair C1 or replace the spring
if necessary.
Repair the C1; detect and replace the
sealing ring or shaft if necessary.
Repair the C1; detect and modify the valve
if necessary.
Repair the C1; detect and replace the ball
spool if necessary.
B2 brake belt is burnt. In
R-Gear- without manual
1
st-Gear. The rear brake belt is adjusted incorrectly or
damaged.
The low speed R-Gear /1
st-Gear ball spool
has displacement. Detect and adjust the brake belt if
necessary.
Detect and reinstall the ball spool if
necessary.
The torque converter is
locked hardly or is not
locked. The torque converter combination regulator
is in rear position. Detect and modify the valve if
necessary.