ISUZU AXIOM 2002 Service Repair Manual

7A1±34
TRANSMISSION CONTROL SYSTEM (4L30±E)

When diagnosing for an intermittent short or open
connection, move the wiring harness while watching
the test equipment for a change.

First diagnose and clear any engine DTCs or TP
Sensor codes. Then inspect for any transmission
DTCs that may have reset.Test Description
The number below refers to the step number on the
diagnostic chart:
3. This test checks PCM and associated wiring up to
the 7±way connector. If the voltage increases to
match chart the problem is isolated to the
transmission wiring.
DTC P0711 Transmission Fluid Temperature (TFT) Sensor Performance
StepActionYe sNo
1Was the Powertrain On±Board Diagnostic (OBD) System Check
performed?
Go to Step 2
Go to OBD
System Check
Refer to
Driveability and
Emissions in
Engine section
2Perform the transmission fluid checking procedure. Refer to
Checking Transmission Fluid Level and Condition in Automatic
Transmission (4L30±E) section.
Did you perform the fluid checking procedure?
Go to Step 3
Go to Checking
Transmission
Fluid Level and
Condition in
Automatic
Transmission
(4L30±E) section
31. Install the scan tool.
2. With the engine ªoffº, turn the ignition switch to the ªonº
position.
NOTE: Before clearing DTCs, use the scan tool in order to record
the Freeze Frame and Failure Records for reference. The Clear
Info function will erase the data.
3. Record the DTC Freeze Frame and Failure Records.
4. Select TFT on the scan tool.
5. While observing the scan tool display, move or massage the
engine wiring harness from PCM connectors E35±66 and
E35±20 to the transmission 7±way connector E±42.
Does the TFT change by more than +20
C (36
F)?
Go to Step 6Go to Step 4
41. Turn the ignition ªoffº.
2. Disconnect the transmission 7±way connector E±42.
3. Install Jumper Harness on the transmission side of the 7±way
connector E±42.
4. Using the J39200 DVOM and J35616 Connector Test Adapter
Kit, connect the DVOM leads from terminal E42±4(F) to
terminal E42±1(E).
5. Set the DVOM on MIN/MAX to measure resistance.
6. Record the TFT sensor resistance.
7. Move or massage the automatic transmission wiring harness
assembly from the PCM to the TFT sensor connector.
(See Transmission Fluid Temperature (TFT) Sensor
Specifications.)
Does the DVOM MAX display a resistance greater than the value
recorded in Action item 6 of this step?
Go to Step 7Go to Step 5
5Does the DVOM MIN display a resistance less than the value
recorded in Action item 6 of step 4?
Go to Step 8Ð
6Inspect circuit RED/BLK and RED/WHT of the engine wiring
harness for an intermittent open or short condition. Repair the
circuits if necessary.
Did you find a problem?
Go to Step 12Go to Step 11

TRANSMISSION CONTROL SYSTEM (4L30±E)7A1±35
DTC P0711 Transmission Fluid Temperature (TFT) Sensor Performance (Cont'd)
StepNo Ye s Action
7Inspect the automatic transmission wiring harness assembly for
an intermittent open in circuits RED/BLK and RED/WHT.
Did you find a problem?
Go to Step 9Go to Step 10
8Inspect the automatic transmission wiring harness assembly for
an intermittent shorted condition in circuits RED/BLK and
RED/WHT.
Did you find a problem?
Go to Step 9Go to Step 10
9Replace the automatic transmission wiring harness assembly.
Is the replacement complete?
Go to Step 12Ð
10Replace TFT Sensor. Refer to Transmission Oil Temperature
Sensor (Main Case) in Automatic Transmission (4L30±E) section.
Is the replacement complete?Go to Step 12Ð
11Replace the PCM. Refer to Powertrain Control Module (PCM) in
Automatic Transmission (4L30±E) section.
Is the replacement complete?Go to Step 12Ð
12In order to verify your repair, perform the following procedure.
1. Select DTC.
2. Select Clear Info.
3. Drive the vehicle and ensure the following conditions are met:

The TFT changes by more than 2.25
C (4.05
F) for 11
seconds since startup.

The TFT does not change by more than 20
C (36
F) within
0.200 second for a period of at least 11 seconds.
4. Select Specific DTC.
5. Enter DTC P0711.
Has the test run and passed?
System OK
Begin the
diagnosis again
Go to
Step 1

7A1±36
TRANSMISSION CONTROL SYSTEM (4L30±E)
DTC P0712 Transmission Fluid Temperature (TFT) Sensor Circuit Low Input
D07R200004
Circuit Description
The TFT sensor is a thermister that controls the signal
voltage to the PCM. The PCM supplies a 5±volt reference
signal to the sensor on circuit RED/BLK. When the
transmission fluid is cold, the sensor resistance is high.
The PCM detects high signal voltage. As the
transmission fluid temperature increases to the normal
operating temperature of 100
C (212
F), the sensor
resistance becomes less and the voltage decreases to
1.5 to 2 volts. With transmission fluid over temperature
and DTC P0218 also set, check the transmission cooling
system.
This DTC detects a continuous short to ground in the TFT
signal circuit or the TFT sensor. This is a type ªDº DTC.
Conditions For Setting The DTC

Battery voltage is between 10 and 16 volts.

Ignition is ªonº.

TFT sensor indicating a voltage less than 0.4 volts.

All conditions met for 20 seconds.
Action Taken When The DTC Sets

Transmission default temperature will be:
80
C (176
F) if engine temperature code is set.
100
C (212
F) if engine temperature is warm.
80
C (176
F) if engine run time is greater than 5
minutes.
21
C (69.8
F) if engine run time is less than 5
minutes.

The PCM will not illuminate the Malfunction Indicator
Lamp (MIL).
Conditions For Clearing The DTC

The DTC can be cleared from the PCM history by
using a scan tool.
The DTC will be cleared from history when the vehicle
has achieved 40 warmup cycles without a failure
reported.

The PCM will cancel the DTC default actions when
the fault no longer exists and the ignition is cycled ªoffº
long enough to power down the PCM.
Diagnostic Aids

Check harness routing for a potential short to ground
in circuit RED/BLK. Scan tool TFT display should rise
steadily to about 100
C (212
F), then stabilize.

Inspect the wiring for poor electrical connection at the
PCM and transmission 7-way connector. Look for
possible bent, backed out, deformed or damaged
terminals. Check for weak terminal tension as well.
Also check for a chafed wire that could short to bare
metal or other wiring. Inspect for a broken wire inside
the insulation.

When diagnosing for a possible intermittent short or
open condition, move the wiring harness while
observing test equipment for a change.

The temperature to resistance value scale may be
used to test the TFT sensor at the various
temperature levels to evaluate the possibility of a
ªskewedº (mis±scaled) sensor.
A ªskewedº sensor could result in delayed garage
shifts or TCC complaints.

Verify customer driving habits, trailer towing, etc.
Test Description
The numbers below refer to the step numbers on the
diagnostic chart:
3. This test checks for a short to ground or a ªskewedº
sensor.
4. This test checks for an internal fault within the
transmission by creating an open.

TRANSMISSION CONTROL SYSTEM (4L30±E)7A1±37
DTC P0712 Transmission Fluid Temperature (TFT) Sensor Circuit Low Input
StepActionYe sNo
1Were you sent here from the ªPowertrain On±Board Diagnostic
(OBD) System Checkº?
Go to Step 2
Go to OBD
System Check
Refer to
Driveability and
Emissions in
Engine section
2Perform the transmission fluid checking procedure. Refer to
Checking Transmission Fluid Level and Condition in Automatic
Transmission (4L30±E) section
Was the fluid checking procedure performed?
Go to Step 3
Refer to
Checking
Transmission
Fluid Level and
Condition in
Automatic
Transmission
(4L30±E) section
31. Install the scan tool.
2. With the engine ªoffº, turn the ignition switch ªonº.
NOTE: Before clearing DTC(s), use the scan tool to record ªFreeze
Frameº and ªFailure Recordsº for reference, as data will be lost
when the ªClear Infoº function is used.
3. Record the DTC ªFreeze Frameº and ªFailure Recordsº.
Does the scan tool display a TFT sensor signal voltage less than
0.4 volts?
Go to Step 4
Go to Diagnostic
Aids
41. Turn the ignition ªoffº.
2. Disconnect the transmission 7±way connector E±42.
3. Turn the ignition ªonº.
Does the TFT signal voltage change to match the voltage 4.92
volts?
Go to Step 5Go to Step 10
5Using the J39200 DVOM, measure the resistance between
terminals E42±4(F) and E42±1(E).
Is the resistance within specifications? (See Transmission Fluid
Temperature (TFT) Sensor Specifications.)
Go to Diagnostic
Aids
Go to Step 6
61. Disconnect the transmission 7±way connector E±42.
2. Using the J39200 DVOM, measure the resistance between
terminals E42±4(F) and E42±1(E).
Is the resistance within specifications? (See Transmission Fluid
Temperature (TFT) Sensor Specifications.)
Go to Diagnostic
Aids
Go to Step 7
71. Remove the transmission oil pan. Refer to Transmission Oil
Temperature Sensor (Main Case) in Automatic Transmission
(4L30±E) section.
2. Check the internal wiring harness for a short to ground.
Was a problem found?
Go to Step 9Go to Step 8
81. Disconnect the internal wiring harness at the TFT sensor.
2. Measure the resistance of the TFT sensor.
Is the resistance within specifications? (See Transmission Fluid
Temperature (TFT) Sensor Specifications.)
Go to Diagnostic
Aids
Go to Step 9
9Replace the TFT Sensor.
Is the replacement complete?
Go to Step 13Ð
10Check circuit RED/BLK for a short to ground.
Was a problem found?
Go to Step 13Go to Step 11

7A1±38
TRANSMISSION CONTROL SYSTEM (4L30±E)
DTC P0712 Transmission Fluid Temperature (TFT) Sensor Circuit Low Input (Cont'd)
StepNo Ye s Action
11Check the PCM for faulty connections.
Was a problem found?
Go to Step 13Go to Step 12
12Replace the PCM. Refer to Powertrain Control Module (PCM) in
Automatic Transmission (4L30±E) section.
Is the replacement complete?Go to Step 13Ð
131. After the repair is complete, use the scan tool to select ªDTCº,
then ªClear Infoº function and ensure the following conditions
are met:
TFT sensor indicates a voltage greater than 0.33 volts for 2
seconds.
2. Review the scan tool ªDTC infoº.
Has the last test failed or is the current DTC displayed?
Begin diagnosis
again
Go to
Step 1
Repair verified
Exit DTC table

TRANSMISSION CONTROL SYSTEM (4L30±E)7A1±39
DTC P0713 Transmission Fluid Temperature (TFT) Sensor Circuit High Input
D07R200004
Circuit Description
The TFT sensor is a thermistor that controls the signal
voltage to the PCM. The PCM supplies a 5±volt reference
signal to the sensor on circuit RED/BLK. When the
transmission fluid is cold, the sensor resistance is high
and the PCM will sense high signal voltage. As the
transmission fluid temperature warms to the normal
operating temperature of 100
C (212
F), the sensor
resistance becomes less and the voltage decreases to
about 1.5 to 2 volts.
This DTC detects a continuous open or short to power in
the TFT signal circuit or the TFT sensor. This is a type ªDº
DTC.
Conditions For Setting The DTC

Battery voltage is between 10 and 16 volts.

Ignition is ªonº.

TFT sensor indicating a voltage greater than 4.86
volts.

All conditions met for 20 seconds.
Action Taken When The DTC Sets

Transmission default temperature will be:
80
C (176
F) if engine temperature code is set.
100
C (212
F) if engine temperature is warm.
80
C (176
F) if engine run time is greater than 5
minutes.
21
C (69.8
F) if engine run time is less than 5
minutes.

The PCM will not illuminate the Malfunction Indicator
Lamp (MIL).
Conditions For Clearing The DTC

The DTC can be cleared from the PCM history by
using a scan tool.
The DTC will be cleared from history when the vehicle
has achieved 40 warmup cycles without a failure
reported.

The PCM will cancel the DTC default actions when
the fault no longer exists and the ignition is cycled ªoffº
long enough to power down the PCM.
Diagnostic Aids

Inspect the wiring for poor electrical connection at the
PCM and transmission 7-way connector. Look for
possible bent, backed out, deformed or damaged
terminals. Check for weak terminal tension as well.
Also check for a chafed wire that could short to bare
metal or other wiring. Inspect for a broken wire inside
the insulation.

When diagnosing for a possible intermittent short or
open condition, move the wiring harness while
observing test equipment for a change.

Scan tool displays transmission fluid temperature in
degrees. After transmission is operating, the
temperature should rise steadily to about 100
C
(212
F), then stabilize.

The temperature to resistance value scale may be
used to check the TFT sensor at the various
temperature levels to evaluate the possibility of a
ªskewedº (mis±scaled) sensor.
A ªskewedº sensor could result in hard shifts or TCC
complaints.
Test Description
The numbers below refer to the step numbers on the
diagnostic chart:
3. This check verifies problem in the TFT sensor circuit.
4. This test simulates a TFT sensor DTC P0712. If the
PCM recognizes the low signal voltage (high
temperature), and the scan tool displays 146
C
(295
F) or greater, the PCM and wiring are OK.
5. This test checks the TFT sensor and internal wiring
harness.

7A1±40
TRANSMISSION CONTROL SYSTEM (4L30±E)
DTC P0713 Transmission Fluid Temperature (TFT) Sensor Circuit High Input
StepActionYe sNo
1Were you sent here from the ªPowertrain On±Board Diagnostic
(OBD) System Checkº?
Go to Step 2
Go to OBD
System Check
Refer to
Driveability and
Emission in
Engine section
2Perform the transmission fluid checking procedure.
Refer to
Checking Transmission Fluid Level and Condition in
Automatic Transmission (4L30±E) section.
Was the fluid checking procedure performed?
Go to Step 3
Refer to
Checking
Transmission
Fluid Level and
Condition in
Automatic
Transmission
(4L30±E) section
31. Install the scan tool.
2. With the engine ªoffº, turn the ignition switch ªonº.
NOTE: Before clearing DTC(s), use the scan tool to record ªFreeze
Frameº and ªFailure Recordsº for reference, as data will be lost
when the ªClear Infoº function is used.
3. Record the DTC ªFreeze Frameº and ªFailure Recordsº.
Does the scan tool display a TFT sensor signal voltage greater
than 4.86 volts?
Go to Step 4
Go to Diagnostic
Aids
41. Turn the ignition ªoffº.
2. Disconnect the transmission 7±way connector E±42.
3. Install a fused jumper wire from terminal E42±4(F) to
E42±1(E) on the engine harness.
4. Turn the ignition ªonº.
Does the TFT signal voltage drop to less than 0.4 volts?
Go to Step 5Go to Step 10
51. Turn the ignition ªoffº.
2. Using the J39200 DVOM, measure the resistance between
terminals E42±4(F) and E42±1(E).
Is the resistance within specifications? (See Transmission Fluid
Temperature (TFT) Sensor Specifications.)
Go to Diagnostic
Aids
Go to Step 6
61. Disconnect the transmission 7±way connector E±42.
2. Using the J39200 DVOM, measure the resistance between
terminals E42±4(F) and E42±1(E).
Is the resistance within specifications? (See Transmission Fluid
Temperature (TFT) Sensor Specifications.)
Go to Diagnostic
Aids
Go to Step 7
71. Remove the transmission oil pan.
2. Check the internal wiring harness for an open. Refer to
Transmission Oil Temperature Sensor (Main Case) in
Automatic Transmission (4L30±E) section.
Was a problem found and corrected?Go to Step 14Go to Step 8
81. Disconnect the internal wiring harness at the TFT sensor.
2. Measure the resistance of the TFT sensor.
Is the resistance within specifications? (See Transmission Fluid
Temperature (TFT) Sensor Specifications.)
Go to Diagnostic
Aids
Go to Step 9
9Replace TFT sensor. Refer to Transmission Oil Temperature
Sensor (Main Case) in Automatic Transmission (4L30±E) section.
Is the replacement complete?Go to Step 14Ð

TRANSMISSION CONTROL SYSTEM (4L30±E)7A1±41
DTC P0713 Transmission Fluid Temperature (TFT) Sensor Circuit High Input (Cont'd)
StepNo Ye s Action
10Check circuit RED/BLK for an open or short to B+.
Was a problem found?
Go to Step 14Go to Step 11
11Check circuit RED/WHT for an open.
Was a problem found?
Go to Step 14Go to Step 12
12Check the PCM for faulty or intermittent connections.
Was a problem found?
Go to Step 14Go to Step 13
13Replace the PCM. Refer to Powertrain Control Module (PCM) in
Automatic Transmission (4L30±E) section.
Is the replacement complete?Go to Step 14Ð
141. After the repair is complete, use the scan tool to select ªDTCº,
then ªClear Infoº function and ensure the following conditions
are met:
2. TFT sensor indicates a voltage less than 4.92 volts for 2
seconds.
3. Review the scan tool ªDTC Infoº.
Has the last test failed or is the current DTC displayed?
Begin diagnosis
again
Go to
Step 1
Repair verified
Exit DTC table

7A1±42
TRANSMISSION CONTROL SYSTEM (4L30±E)
DTC P0719 Brake Switch Circuit Low (Stuck On)
D07R200007
Circuit Description:
The brake switch indicates brake pedal status to the
Powertrain Control Module (PCM). The brake switch is a
normally±closed switch that supplies battery voltage on
circuit BRN/RED to the PCM. Applying the brake pedal
opens the switch, interrupting voltage to the PCM. When
the brake pedal is released, the PCM receives a constant
voltage signal. If the PCM receives a zero voltage signal
at the brake switch input, and the Torque Converter
Clutch (TCC) is engaged, the PCM de±energizes the
Torque Converter Clutch Solenoid Valve (TCC Sol.
Valve). The PCM disregards the brake switch input for
TCC scheduling if there is a brake switch circuit fault
(Refer to
Diagnostic Aids).
When the PCM detects an open brake switch circuit (0
volts, low input) during accelerations, then DTC P0719
sets. DTC P0719 is a type D DTC.
Conditions For Setting The DTC

No OSS Assy. DTCs P0722 or P0723.

The PCM detects an open brake switch or circuit (0
volts) for 15 minutes without changing for 2 seconds,
and the following events occur seven consecutive
times.

The vehicle speed is less than 8 km/h (5 mph).

then the vehicle speed is 8±32 km/h (5±20 mph) for
4 seconds.

then the vehicle speed is greater than 32 km/h (20
mph) for 4 seconds.
Action Taken When The DTC Sets

The PCM does not illuminate the Malfunction
Indicator Lamp (MIL).

DTC P0719 stores in PCM history.
Conditions For Clearing The DTC

A scan tool can clear the DTC from the PCM history.
The PCM clears the DTC from the PCM history if the
vehicle completes 40 warm±up cycles without a
failure reported.

The PCM cancels the DTC default actions when the
fault no longer exists and the ignition is OFF long
enough in order to power down the PCM.
Diagnostic Aids

Inspect the wiring for poor electrical connections at
the PCM and brake switch. Look for possible bent,
backed out, deformed or damaged terminals. Check
for weak terminal tension as well. Also check for a
chafed wire that could short to bare metal or other
wiring. Inspect for a broken wire inside the insulation.

When diagnosing for a possible intermittent short or
open condition, move the wiring harness while
observing test equipment for a change.

Check customer driving habits and/or unusual driving
conditions (i.e. stop and go, highway).

Check brake switch for proper mounting and
adjustment.

TRANSMISSION CONTROL SYSTEM (4L30±E)7A1±43
Test Description
The numbers below refer to the step numbers on the
diagnostic chart:
3. This step isolates the brake switch as a source for
setting the DTC.