brake ISUZU TF SERIES 2004 Workshop Manual

7A2-72 DIAGNOSIS (JR405E)
DTC P1863 (Flash Code 28) High Clutch Pressure Switch Failure



Control Valve

TCM
B1
B12
B20
RED/YEL
WHT/BLK
2-4 Brake Pressure SW
Terminal
Assembly
YEL
E54 (7)
(12)
(1)H23 (12)
(10)C95 (1)
(12)
(20)
RED/YEL
YEL
WHT/BLK
L&R Brake Pressure SW
High Clutch Pressure SWH22 (8)




Pre-setting Condition:

No gear shifting.

No Check Trans indicator lamp.

No system voltage failure.

No inhibitor switch failure.

2-4 brake duty solenoid 0 or 100 %.

ATF temperature more than 60 C.

ATF input voltage more than 0.1V.

Engine speed more than 500 rpm.

DIAGNOSIS (JR405E) 7A2-73

Setting Condition:

During the running, the high clutch pressure switch does not turn on though hydraulic pressure is supposed to be
generated in high clutch.
(All pre-setting conditions are met for 2.5 seconds, high clutch pressure switch off, 2-4 brake pressure switch on
and gear ratio more than 0.65 or less than 0.74 with 4th gear in D range.)
Or

During the running, the high clutch pressure switch does not turn off though no hydraulic pressure is supposed
to be generated in the high clutch.
(All pre-setting conditions are met for 2.5 seconds, high clutch pressure switch on in P, R or N range.)

Fail Safe:

No fail safe function

Possible Cause:

High clutch duty solenoid malfunction.

High clutch pressure switch open circuit or short circuit.

Open circuit, short circuit to battery or short circuit to ground of the harness between high clutch pressure switch
terminal 1 and TCM terminal B20 (C95).

High clutch hydraulic circuit malfunction in the control valve.

Poor connection of each connector.

Reference:
When the high clutch pressure switch is operated, following signal is outputted.
Measurement terminal: B20 (C95) and B22 (C95)
-At other than 3rd or 4th gear: More than 10V
-At 3rd or 4th gear: Less than 1V

DIAGNOSIS (JR405E) 7A2-77
Step Action Yes No
6 Is the quantity of ATF correct?
Go to Step 7
Correct the quantity of
ATF.
Go to Step 9
7 Connect the Tech 2 and test the solenoids of respective
solenoids for low & reverse brake, 2-4 brake, high clutch and
low clutch. Is operation sound heard from each solenoid?
Go to Step 8
Replace the solenoid
that does not generate
the operation sound.
Go to Step 9
8 Check the line pressure during the idling and at the engine stall
speed. Is the line pressure correct?
Go to Step 10
Either control valve, oil
pump or power train
parts (clutch, brake)
will be faulty. Replace
or overhaul the
transmission unit.
Go to step 10
9 Run the vehicle, and is the gear shifted from 1st to 4th
correctly?
Go to Step 10
Either control valve, oil
pump or power train
parts (clutch, brake)
will be faulty. Replace
or overhaul the
transmission unit.
Go to step 10
10 Clear the DTC from the memory and perform the work after
repair. Is the same DTC code outputted again in the
subsequent DTC check?
Replace the TCM Go to Step 11
11 Are the other DTCs outputted?
Go to Other DTC
Section Action is completed

7A2-78 DIAGNOSIS (JR405E)
DTC P1750 (Flash Code 51) Low & Reverse Brake Fail-safe Valve Failure

Low & Reverse Brake Fail Valve (B)Control Valve Upper Body
Low & Reverse Brake Fail Valve (A)Control Valve Lower Body

Setting Condition:

When the oil pressure generated and low & reverse brake pressure switch operates off/on twice, the TCM
detected an operation failure of the low & reverse brake fail-safe valve in D, 3, 2, L range.

Fail Safe:

When the vehicle is running, the gear position selected at the trouble detection is held and the lock-up is
inhibited.

After the vehicle stopped, all solenoid operations stop (OFF) and the gear is fixed to the 3rd.

Possible Cause:

Stick of low & reverse brake fail-safe valve.

Low & reverse brake pressure switch does not turn on.

Short circuit to ground of harness low & reverse brake pressure switch.

Poor connection of each connector of harness in low & reverse brake pressure switch.

DIAGNOSIS (JR405E) 7A2-79

Step Action Yes No
1 Turn the key switch on and check the DTC. Is only the DTC for
low & reverse brake fail-safe valve failure outputted?
Go to Step 2
Go to Other DTC
Section
2 Clear the DTC from the memory. Turn the key switch off once,
and then start the engine. Does the CHECK TRANS blink
when the D range is selected and about 10 seconds elapsed?
Go to Other DTC
Section Go to Step 3
3 Run the vehicle, shift the gear from 1st to 4th, stop the vehicle,
and again shift the gear from 1st to 4th. Does the CHECK
TRANS blink at this time?
Go to Step 4
The low & reverse
brake fail-safe valve
may be faulty
temporarily.
Go to step 5
4 Turn the key switch on and check the DTC. Is only the DTC for
the low & reverse brake fail-safe valve failure outputted?
Repair or replace the
control valve.
Go to Step 5
Go to Other DTC
Section
5 Clear the DTC from the memory and perform the work after
repair. Is the same DTC code outputted again in the
subsequent DTC check?
Replace the TCM Go to Step 6
6 Are the other DTCs outputted?
Go to Other DTC
Section Action is completed

7A2-80 DIAGNOSIS (JR405E)
DTC P1755 (Flash Code 52) 2-4 Brake Fail-safe Valve Failure

Control Valve Upper Body2-4 Brake Fail Valve (B)
Control Valve Lower Body2- 4 Br ake Fai l Val ve ( A)

Setting Condition:

When the oil pressure generated and 2-4 brake pressure switch operates off/on twice, the TCM detected an
operation failure of the low & reverse brake fail-safe valve in D, 3, 2, L range.

Fail Safe:

When the vehicle is running, the gear position selected at the trouble detection is held and the lock-up is
inhibited.

After the vehicle stopped, all solenoid operations stop (OFF) and the gear is fixed to the 3rd.

Possible Cause:

Stick of 2-4 brake fail-safe valve.

2-4 brake pressure switch does not turn on.

Short to ground of harness 2-4 brake pressure switch.

Faulty fitting of each connector of harness in 2-4 brake pressure switch.

DIAGNOSIS (JR405E) 7A2-81

Step Action Yes No
1 Turn the key switch on and check the DTC. Is only the DTC for
2-4 brake fail-safe valve failure outputted?
Go to Step 2
Go to Other DTC
Section
2 Clear the DTC from the memory. Turn the key switch off once,
and then start the engine. Does the CHECK TRANS blink when
the D range is selected and about 10 seconds elapsed?
Go to Other DTC
Section Go to Step 3
3 Run the vehicle, shift the gear from 1st to 4th, stop the vehicle,
and again shift the gear from 1st to 4th. Does the CHECK
TRANS blink at this time?
Go to Step 4
The 2-4 brake fail-safe
valve may be faulty
temporarily.
Go to step 5
4 Turn the key switch on and check the DTC. Is only the DTC for
the 2-4 brake fail-safe valve failure outputted?
Repair or replace the
control valve.
Go to Step 5
Go to Other DTC
Section
5 Clear the DTC from the memory and perform the work after
repair. Is the same DTC code outputted again in the
subsequent DTC check?
Replace the TCM Go to Step 6
6 Are the other DTCs outputted?
Go to Other DTC
Section Action is completed

DIAGNOSIS (JR405E) 7A2-83
SYMPTOM DIAGNOSIS

Symptom Condition Description
Vehicle does not
run In D, 3, 2, L, and R ranges Vehicle does not run though the accelerator
pedal is stepped on. A1
In R range Vehicle does not run in R range only. A2
It runs normally in D, 3, 2, and L ranges.
In D, 3, 2, and L ranges Vehicle does not run in D, 3, 2, and L
ranges only. A3
It runs normally in R range.
Trouble at
starting Vehicle runs in N range Creep appears in N range. B1
Vehicle moves unless the brake pedal is
stepped on in N range.
Poor acceptation Starting acceleration is poor. B2
Engine races up during starting (slip)
The engine speeds up but vehicle speed
does not increase when the accelerator
pedal is stepped on at the starting.
B3
Large shock when shift lever is changed to
N to D range or N to R range
Large shock is felt when selecting D or R
range from N range during the idling after
warming up.
B4
Engine stalls when selecting from N range
to R, D, 3, 2, or L range
The engine stalls when selecting from N or
P range to a run range during the engine
idling.
B5
Engine starter does not run in P or N rangeThe engine starter does not run though the
P or N range is selected. B6
Engine starter runs except in P or N range The engine starter runs though the R or D,
3, 2or L range is selected. B7
Extended time lag when shift lever is
changed to N to D
The shift time lag is longer than standard
value when shift lever is changed to N to D.B8
Extended time lag when shift lever is
changed to N to R
The shift time lag is longer than standard
value when shift lever is changed to N to R.B9
Brake is applied in R range Brake is applied suddenly in R range. B10
Insufficient starting or shaking in D range Insufficient starting or shaking in D range. B11
Noise or vibration Noise or vibration is generated in the vicinity
of AT at starting. B12

DIAGNOSIS (JR405E) 7A2-85
SYMPTOM DIAGNOSIS

Symptom Condition Description
Faulty shifting Engine race up (slip) when gear is shifted up
to 1st to 2nd
The engine speed up when the accelerator
pedal is stepped on for acceleration and the
gear is shifted up.
C1
Engine race up (slip) when gear is shifted up
to 2nd to 3rd
The engine speed up when the accelerator
pedal is stepped on for acceleration and the
gear is shifted up.
C2
Engine race up (slip) when gear is shifted up
to 3rd to 4th
The engine speed up when the accelerator
pedal is stepped on for acceleration and the
gear is shifted down or for kick-down during
steady run.
C3
Engine race up (slip) when gear is shift
down or kick-down to 4th to 3rd
The engine speed up when the accelerator
pedal is stepped on for acceleration and the
gear is shifted down or for kick-down.
C4
Engine race up (slip) when gear is shift
down or kick-down to 4th to 2nd
The engine speed up when the accelerator
pedal is stepped on for acceleration and the
gear is shifted down or for kick-down.
C5
Engine race up (slip) when gear is shift
down or kick-down to3rd to 2nd
The engine speed up when the accelerator
pedal is stepped on for acceleration and the
gear is shifted down or for kick-down.
C6
Engine race up (slip) when gear is shift
down or kick-down to4th or 3rd to 1st
The engine speed up when the accelerator
pedal is stepped on for acceleration and the
gear is shifted down or for kick-down.
C7
Engine race up (slip) others
The engine speed up when the accelerator
pedal is stepped on for acceleration and the
gear is shifted down or for kick-down during
steady run.
C8
Braking feel when gear is shifted up to 1st to
2nd
Brake feeling appears when the accelerator
pedal is stepped on for acceleration and the
gear is shifted up.
C9
Braking feel when gear is shifted up to 2nd
to 3rd
Brake feeling appears when the accelerator
pedal is stepped on for acceleration and the
gear is shifted up.
C10
Braking feel when gear is shifted up to 3rd
to 4th
Brake feeling appears when the accelerator
pedal is stepped on for acceleration and the
gear is shifted up.
C11
Large shock when gear is shifted to 1st to
2nd or 2nd to 1st
Large shock is felt when the accelerator
pedal is stepped on for acceleration and the
gear is shifted up or down.
C12
Large shock when gear is shifted to 2nd to
3rd or 3rd to 2nd
Large shock is felt when the accelerator
pedal is stepped on for acceleration and the
gear is shifted up or down.
C13

DIAGNOSIS (JR405E) 7A2-89
Symptom Condition Description
Faulty during the
running Low maximum speed or poor acceleration Starting acceleration is poor. F1
Acceleration is slow though the accelerator
pedal is stepped on during the running.
Engine races up during acceleration (slip)
The engine speeds up but vehicle speed
does not increase when the accelerator
pedal is stepped on at the starting.
F2

Only the engine speeds up but vehicle
speed does not increase when the
accelerator pedal is stepped on for
acceleration during the running.

Noise or vibration during the running in R, D,
3, 2, or L range
Noise or vibration is generated in the vicinity
of AT during the running. F3
Engine brake does not in apply L range
The engine brake does not apply, allowing
the vehicle to run freely when the
accelerator pedal is released at low speed in
L range.
F4
Engine stalls before vehicle stops from
running
The engine stalls simultaneously with the
vehicle stop when the brake pedal is
stepped on to stop the vehicle during the
running.
F5
Faulty in the
stopping
Vehicle moves in P range, or parking gear is
not disengaged other than P range
Vehicle moves though it stops at a slope
and P range is selected. G1

The engine stalls and vehicle does not move
though other than P range is selected and
the accelerator pedal is stepped on.

Creep force is large
Vehicle accelerates in D, 3, 2, L, and R
ranges though the accelerator pedal is not
stepped on.
G2
Creep force is small Vehicle does not move though a run range
is selected on a flat road during the idling. G3
Large noise during idling with the vehicle in
stop state
The transmission is noisy during the idling
speed in all ranges. G4
Faulty lock-up Judder occurs at the lock-up The vehicle body judders at lock-up. H1
Large lock-up shock Large shock is felt at lock-up. H2
Lock-up point is high or low Lock-up point is excessive high or low. H3
No lock-up No lock-up Lockup is not performed in spite of the lock-
up area. I1