2002 ISUZU AXIOM check engine

7A±11 AUTOMATIC TRANSMISSION (4L30±E)
Fluid Condition
FLUID CONDITION
NORMAL*CONTAMINATED
COLORRED OR LIGHT
BROWNBROWNNON±TRANSPARENT
/ PINKBROWN
DRAIN
REQUIRED?NOYESYESYES
CONTAMINA±
TIONNONEVery small amount of
foreign material in
bottom of panContamination by cool-
ant or other sourceLarge pieces of metal
or other foreign
material in bottom of
pan
CORRECT
LEVEL AND
CONDITION
1. LOW LEVEL:
A. Add fluid to
obtain proper
level & check for
external leaks.
B. Correct cause of
leak.
2. HIGH LEVEL:
± Remove excess
fluid± Remove both pans
± Change filter
± Flush cooler
± Add new fluid
± Check level± Repair/replace
radiator cooler
± Transmission
overhaul required
± Check for:

Damaged plates
and seals

Contaminated
solenoids
± Flush cooler
± Add new fluid
± Check level± Transmission
overhaul required
± Flush cooler and
cooler lines
± Add new fluid
± Check level
*Fluid should be changed according to maintenance
schedule.
Test Driving
Some 4L30±E automatic transmission complaints will
require a test drive as a part of the diagnostic procedure.
Some codes will not set unless the vehicle is moving. The
purpose of the test drive is to duplicate the customer's
complaint condition and set a current Powertrain Control
Module (PCM) trouble code. Perform this procedure
before each 4L30±E automatic transmission repair, and
again after repairs are made.
IMPORTANT:

Duplicate the condition under which the customer's
complaint was observed.

Depending on the complaint, the line pressure gauge
and the scan tool may be required during the test
drive.

During the test drive, it is important to record all
necessary data from the areas being monitored, for
use in diagnosis. Also listen for and note any unusual
noises.
The following procedure should be used to test drive
4L30±E automatic transmission complaint vehicles:
1. Turn the ignition ON without starting the engine.
Check that the ªCHECK TRANSº lamp comes on for
approximately 2 seconds and then goes out and
remains out.

If the lamp is flashing, GO TO Check Trans
Indicator in Transmission Control System
(4L30±E) section.
If no serial data is present, GO TO OBD System
Check. Refer to
Driveability and Emissions in
Engine section.

If the lamp stays ON or stays OFF, GO TO ªCheck
Transº Check in Transmission Control System
(4L30±E) section.
2. Drive the vehicle. During the test drive, be sure that
the transmission achieves normal operating
temperature (approx. 20 minutes).
Allow the transmission to go through all of its gear
ranges, checking shift timing and firmness. Duplicate
the owner's complaint condition as closely as
possible during the test drive.
3. If, during the test drive, the ªCHECK TRANSº lamp
comes on, use the scan tool to check for trouble
codes.
4. If, during the test drive, a problem is felt, but the
ªCHECK TRANSº lamp does not come on and no
trouble codes are present, drive the vehicle with the
PCM disconnected (manually shifting the vehicle).

In Manual L, the vehicle operates in first gear.

In Manual 2, the vehicle operates in third gear.

In Manual 3 or ªDº, the vehicle operates in fourth
gear.
If the problem still exists with the PCM disconnected,
refer to
Mechanical/Hydraulic Diagnosis in this
section.
5. If no problem has been found at this point, check all
underhood connections that supply power to the PCM
and ignition fuses. Physically and visually inspect all
the PCM harness connectors for loose or corroded
terminals. Inspect the PCM ground points.

7A±12
AUTOMATIC TRANSMISSION (4L30±E)
Mechanical / Hydraulic Diagnosis Check Trans Indicator Chart
Perform Preliminary Inspection First!
F07RT013
When the ªCHECK TRANSº indicator is flashing, it
indicates that a problem related to the transmission, the
Powertrain Control Module (PCM), or the vehicle harness
has occurred.
The system is now operating in a ªBACKUP MODEº
where the risk of further damaging the transmission has
been reduced. The vehicle may be shifted manually.
If the initial problem is intermittent or seldom, switching
the engine OFF/ON might allow normal operation again
until the problem reoccurs.

7A±13 AUTOMATIC TRANSMISSION (4L30±E)
Mechanical / Hydraulic Diagnosis Symptoms Index
Perform Preliminary Inspection First!
CHART
SYMPTOMS
1NO ENGINE START IN NEUTRAL OR PARK
2NO FORWARD GEARS IN ANY RANGE/NO REVERSE
3NO ENGINE BRAKE IN ANY RANGE
4POOR SHIFTING IN ALL GEARS (ALL HARSH OR ALL SOFT)
5aDELAYS IN DRIVE AND REVERSE
5bDELAYS IN REVERSE ONLY
6DIAGNOSTIC TROUBLE CODE (DTC) P0730
7HARSH 1±2 SHIFT
8HARSH 3±4 SHIFT
9a3±2 DOWNSHIFT COMPLAINT
9bHARSH SHIFT WHEN SHIFTING INTO ªDº OR ACCELERATING FROM STOP
9cCOASTDOWN HARSH SHIFT OR CLUNK AT 3±2 DOWNSHIFT
10INTERMITTENT 4TH TO 2ND GEAR DOWNSHIFT AT STEADY SPEED
11ENGINE FLARE AT SHIFTING DURING TURNING ONLY (USUALLY WITH WARM ENGINE)
12ENGINE FLARE DURING 1±2 OR 2±3 SHIFT
13SHUDDER ONLY DURING TORQUE CONVERTER CLUTCH (TCC) APPLYING
14POSSIBLE CAUSES OF TRANSMISSION NOISE
15aPOSSIBLE CAUSES OF LOW LINE PRESSURE
15bPOSSIBLE CAUSES OF HIGH LINE PRESSURE
16POSSIBLE CAUSES OF TRANSMISSION FLUID LEAKS
NOTE: Numbers with parenthesis on the following charts
refer to
Parts List at end of this section.
Chart 1: No Engine Start In Neutral Or Park
StepActionYe sNo
1Does engine start when shift lever moved from drive to neutral
mostly in hot condition?
Go to Step 2Go to Step 3
2Does engine start in park at any condition?Re±test vehicleGo to Step 4
3Does engine also not start in neutral when shift lever moved from
park to neutral?
Go to Step 4Go to Step 5
4Check mode switch (63) setting. Readjust if necessary.
Problems fixed?
Re±test vehicleGo to Step 5
5Check start circuit of mode switch (63) open in neutral.
Was open found?Locate and repair
open(s)Replace mode
switch (63)

7A±14
AUTOMATIC TRANSMISSION (4L30±E)
Chart 2: No Forward Gears In Any Range/No Reverse
StepActionYe sNo
1Check line pressure. Refer to Line Pressure Test in this section.
Was line pressure normal?
Go to Step 2
Use Chart 15a:
Possible Causes
of Low Line
Pressure in this
section
21. Check internal linkage:
± Manual linkage (58) not moving manual valve (326).
2. Check for internal mechanical damage:
± Turbine shaft (506) broken loose.
± Overrun roller clutch (516) broken loose.
Was the problem found?
Repair or replaceÐ
Chart 3: No Engine Brake In Any Range
StepActionYe sNo
1Check line pressure. Refer to Line Pressure Test in this section.
Was line pressure normal?
Go to Step 2
Use Chart 15a:
Possible Causes
of Low Line
Pressure in this
section
21. Check for overrun clutch leaks caused by:
± Damaged piston lip (513)
± Check ball defective (504)
2. Check for overrun lockout valve (705) stuck by foreign
material.
3. Check for leaks at turbine shaft (506) caused by:
± Teflon seal rings damaged (508)
± Excessive wear of turbine shaft bearing surfaces.
Was the problem found?
Repair or replaceÐ

7A±15 AUTOMATIC TRANSMISSION (4L30±E)
Chart 4: Poor Shifting In All Gears (All Harsh Or All Soft)
StepActionYe sNo
1Check line pressure. Refer to Line Pressure Test in this section.
Was line pressure normal?Go to Step 2Go to Step 3
21. Check for these conditions which could affect clutch apply
time:
± Defective band apply solenoid (323).
± Defective servo or/and accumulator piston.
± Excessive clutch piston travel.
2. Check of possible causes of internal leaks:
± Cut or damaged sealing ring(s)
± Damaged sealing gasket(s)
± Check ball missing or out of location in 2nd and 3rd clutch
pistons.
3. Check for causes of burned clutch plates or band.
Was the problem found?
Repair or replaceÐ
3Was the line pressure high?
Go to Step 4
Use Chart 15a:
Possible Causes
of Low Line
Pressure in this
section
4Does DTC P0705 set?
Diagnose those
DTC(s) first
Use Chart 15b:
Possible Causes
of High Line
Pressure in this
section
Chart 5a: Delays In Drive And Reverse
NOTE: A short delay (less than 3 seconds) when first
engaging drive or reverse after allowing vehicle to sit
overnight is normal.
Step
ActionYe sNo
1Check line pressure. Refer to Line Pressure Test in this section.
Was line pressure normal?
More than 3
second delay in
drive and reverse
with engine off 1
hour or less.
Teflon seals (508)
on turbine shaft
damaged. Repair
Use Chart 15a:
Possible Causes
of Low Line
Pressure in this
section.
Chart 5b: Delays In Reverse Only
StepActionYe sNo
1Check line pressure. Refer to Line Pressure Test in this section.
Was line pressure normal?
Go to Step 2
Use Chart 15a:
Possible Causes
of Low Line
Pressure in this
section.
2Main case valve body gasket (88) damaged.
± Reverse check ball (85) in valve body (84) missing or out of
location.
± Check for restrictions at valve body transfer plate orifice.
Was the problem found?
RepairÐ

7A±16
AUTOMATIC TRANSMISSION (4L30±E)
Chart 6: Diagnostic Trouble Code (DTC) P0730
StepActionYe sNo
1Check line pressure. Refer to Line Pressure Test in this section.
Was line pressure normal?
Go to Step 2
Use Chart 15b:
Possible Causes
of High Line
Pressure in this
section
21. 1st and 2nd gear missing or 3rd and 4th gear missing.
Check appropriate shift valve. If OK replace solenoid.
2. No engine brake in any range (All ranges in Drive and Reverse
are OK).
Check for suspected conditions modifying delays to clutch
apply:
± Overrun clutch seal damaged.
± Excessive overrun clutch piston travel.
± Defective 3±4 accumulator piston.
± Causes of internal leaks.
± Causes of burned clutch plates.
3. 1st and 4th gear missing or 2nd and 3rd gear missing.
Shift solenoid A stuck. Replace shift solenoid A.
4. DTC P0730 is set in D range 1st gear above 3500 rpm.
Go to
Step 3.
5. DTC P0730 is set in D range 3rd gear between 55-80 mph.
NOTE: Perform this test within safe and legal limits.
Check for suspected conditions modifying delays to clutch
apply:
± 4th clutch seal damaged.
± Excessive 4th clutch piston travel.
± Defective 3±4 accumulator piston.
± Causes of internal leaks.
± Causes of burned clutch plates.
Was the problem found?
Repair or replaceÐ
3Check 3rd gear in ªDº in winter mode.
Does vehicle move?Shift solenoid A
stuck. Replace
shift solenoid A.
Go to Step 4
4Check for suspected conditions modifying delays to clutch apply:
± 2nd clutch seal damaged.
± Excessive 2nd clutch piston travel.
± Defective accumulator piston.
± Causes of internal leaks.
± Check ball missing or out of location in 2nd clutch.
± Seals cut, damaged or missing.
± Gaskets defective.
± Causes of burned clutch plates.
Was the problem found?
Repair or replaceÐ

7A±18
AUTOMATIC TRANSMISSION (4L30±E)
Chart 9c: Coastdown Harsh Shift Or Clunk At 3±2 Downshift
StepActionYe sNo
1Check line pressure. Refer to Line Pressure Test in this section.
Was line pressure normal?
Go to Step 2
Use Chart 15b:
Possible Causes
of High Line
Pressure in this
section
2Does DTC P1850 set?
Diagnose P1850
first
Replace band
apply solenoid
(PWM) (323)
Chart 10: Intermittent 4TH TO 2ND Gear Downshift At Steady Speed
StepActionYe sNo
1Check for consistent speed sensor reading with scan tool.
Was the reading correct?Replace mode
switch for
intermittent
contact.
Go to Step 2
21. Check for wiring harness damage or short to ground. If OK, go
to
(2).
2. Check transmission speed sensor connections. If OK, go to
(3).
3. Replace transmission speed sensor.
Was the replacement complete?
Ð
Replace speed
sensor.
Chart 11: Engine Flare At Shifting During Turning Only (Usually With Warm Engine)
StepActionYe sNo
1Check for oil leaks at transmission.
Was the problem found?Replace
transmission oil
filter and gasket
Ð
Chart 12: Engine Flare During 1±2 Or 2±3 Shift
StepActionYe sNo
1Check line pressure. Refer to Line Pressure Test in this section.
Was line pressure normal?
Go to Step 2
Use Chart 15a:
Possible Causes
of Low Line
Pressure in this
section
21. Check for a stuck 1±2 accumulator valve (320).
2. Check for servo piston (106) leaks.
3. Check for a stuck band apply solenoid (323).
Was line pressure normal?
Repair or replaceÐ

7A±22
AUTOMATIC TRANSMISSION (4L30±E)
Chart 16: Possible Causes Of
Transmission Fluid Leaks
Before attempting to correct an oil leak, the actual source
of the leak must be determined. In many cases, the
source of the leak may be difficult to determine due to
ªwind flowº around the engine and transmission.
The suspected area should be wiped clean before in-
specting for the source of the leak.Oil leaks around the engine and transmission are gener-
ally carried toward the rear of the vehicle by the air
stream. In determining the source of an oil leak, the fol-
lowing two checks should be made:
1. With the engine running, check for external line
pressure leaks.
2. With the engine off, check for oil leaks due to the
raised oil level caused by drainback of converter oil
into the transmission.
Possible Causes Of Fluid Leaks Due To Sealing Malfunction
240RX008
Legend
(1) Electrical Connector (Main Case) Seal
(2) Transmission Vent (Breather)
(3) Speed Sensor O±Ring
(4) Extension (Adapter) Lip Seal
(5) Extension (Adapter) to Main Case Gasket
(6) Overfill and Oil Drain Screws Gasket
(7) Oil Pan Gasket (Main Case)
(8) Selector Shaft Seal(9) Oil Cooler Connectors (2)
(10) Oil Pan Gasket (Adapter Case)
(11) Converter housing attaching bolts not correctly
torqued
(12) Converter Housing Lip Seal
(13) Line Pressure Tap Plug
(14) Electrical Connector (Adapter Case) Seal
(15) Adapter Case Seal Rings (2)