2002 ISUZU AXIOM ignition

7A1±48
TRANSMISSION CONTROL SYSTEM (4L30±E)
DTC P0723 Automatic Transmission Output Speed Sensor (OSS) Intermittent
D07R200006
Circuit Description
Output speed information is provided to the PCM by the
OSS, which is a permanent magnet (PM) generator. The
PM generator produces a pulsing AC voltage. The AC
voltage level and number of pulses increases as the
speed of the vehicle increases. The PCM then converts
the pulsing voltage to output speed, which is used for
calculations. The vehicle speed can be displayed with a
scan tool.
This DTC detects a fast decrease of output speed when
engine running in a drive gear range. This is a type ªBº
DTC.
Conditions For Setting The DTC
Drive range

Engine running time is greater than 5 seconds.

Output speed is greater than 1300 rpm for 2 second.

NORAW±NOLAST < 200 rpm for 2 seconds.

NORAW: Latest raw data of output shaft speed.

NOLAST: Fitered previous data of output speed.

Transmission negative output speed change is
greater than 1300 rpm.

Conditions met for 3 seconds.
Action During Detection Time

Output speed value is frozen
Action Taken When The DTC Sets

Fixed to 4th gear.

Maximum line pressure.

Inhibit TCC engagement.

For lamp illuminate refer to
DTC type definition (type
B).
Conditions For Clearing The MIL/DTC

The PCM will turn off the MIL and CHECK TRANS
Lamp after three consecutive ignition cycles without a
failure reported.

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

A OSS DTC P0723 will set when output speed has
been detected and is lost.

Inspect the wiring for poor electrical connection at the
PCM. 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.
Test Description
The numbers below refer to the step numbers on the
diagnostic chart:
4. This test checks the OSS circuit.
5. This test checks the integrity of the OSS.
7. This test checks the 5±volt and ground circuit of the
PCM.

TRANSMISSION CONTROL SYSTEM (4L30±E)7A1±49
DTC P0723 Automatic Transmission Output Speed Sensor (OSS) Intermittent
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
21. 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.
4. Raise the drive wheels.
5. Start the engine.
6. Place the transmission in any drive range.
With the drive wheels rotating, does the ªTrans Output Speedº
increase with the drive wheel speed?
Go to Diagnostic
Aids
Go to Step 3
3Check for the most current and/or incorrect calibration.
Is the calibration current?
Go to Step 16Go to Step 4
41. Turn the ignition ªoffº.
2. Disconnect the E35 (RED) PCM connector.
3. Using the J39200 DVOM, measure the resistance between
harness connector terminals E35±22 and E35±55.
Is the reading 3,000 ohms?
Go to Step 5Go to Step 6
51. Select AC volts.
2. Rotate the rear wheels, ensuring the driveshaft is turning.
Is the voltage greater than 0.5 volts?
Go to Step 7Go to Step 8
6Inspect circuits BLU/YEL and BLU/GRN for a poor connection or
an open circuit.
Was a problem found?
Go to Step 17Go to Step 8
71. Reconnect the E35 (RED) PCM connector.
2. Disconnect the OSS harness from the OSS.
3. With the engine ªoffº, turn the ignition ªonº.
4. Using the J 39200 DVOM, measure the voltage at the OSS
harness connector terminals E44±1 and E44±2.
Is the reading between 4.0 to 5.1 volts?
Go to Step 16Go to Step 10
81. Remove the OSS.
2. Check the output shaft speed sensor rotor for damage or
misalignment. Refer to
Speed Sensor (Extension Assembly)
in Automatic Transmission (4L30±E) section.
Was a problem found?Go to Step 17Go to Step 9
9Replace the OSS.
Is the replacement complete?
Go to Step 17Ð
10Was the reading in step 7 less than 4.0 volts?Go to Step 12Go to Step 11
11Was the reading in Step 7 greater than 5.1 volts?Go to Step 15Ð
12Using the J 39200 DVOM to chassis ground, measure the voltage
on circuit BLU/YEL.
Is the reading between 4.0 to 5.1 volts?
Go to Step 13Go to Step 14

TRANSMISSION CONTROL SYSTEM (4L30±E)7A1±51
DTC P0724 Brake Switch Circuit High (Stuck Off)
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 a closed brake switch circuit (12
volts, high input) during decelerations, then DTC P0724
sets. DTC P0724 is a type D DTC.
Conditions For Setting The DTC

No OSS Assy. DTCs P0722 or P0723.

The PCM detects a closed brake switch circuit (12
volts) without changing and the following events
occur seven consecutive times.

The vehicle speed is greater than 32 km/h (20 mph)
for 4 seconds.

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

then the vehicle speed is less than 8 km/h (5 mph).
Action Taken When The DTC Sets

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

DTC P0724 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 connection at the
PCM. 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 traffic
conditions (i.e. stop and go, expressway).

Check brake switch for proper mounting and
adjustment.

7A1±52
TRANSMISSION CONTROL SYSTEM (4L30±E)
Test Description
The numbers below refer to the step numbers on the
diagnostic chart:
2. This step isolates the brake switch as a source for
setting the DTC.
DTC P0724 Brake Switch Circuit High (Stuck Off)
StepActionYe sNo
1Was the Powertrain On±Board Diagnostic (OBD) System Check
performed?
Go to Step 2
Go to Powertrain
OBD System
Check
21. Install the scan tool.
2. With the engine ªoff,º turn the ignition switch to the ªonº
position.
NOTE: Before clearing the DTC(s), use the scan tool in order to
record the ªFailure Recordsº for reference. Using the ªClear Infoº
function will erase the stored ªFailure Recordsº from the PCM.
3. Record the DTC Failure Records, then clear the DTC(s).
4. Select ªBrake Switchº on the scan tool.
5. Disconnect the brake switch connector from the brake switch.
Did the TCC brake switch status change from ªClosedº to ªOpenº?
Go to Step 3Go to Step 4
3Replace the brake switch.
Is the replacement complete?
Go to Step 6Ð
4Inspect circuit BRN/RED for a short to B+ condition. Repair the
circuit if necessary.
Did you find a short to B+ condition?
Go to Step 6Go to Step 5
5Replace the PCM.
Is the replacement complete?
Go to Step 6Ð
6In order to verify your repair, perform the following procedure:
1. Select DTC.
2. Select ªClear Infoº.
3. With the engine ªoffº turn the ignition switch to the ªonº position.
4. Apply the brake pedal.
5. Verify that the brake switch status indicates ªOpenº (0 volts) for
2 seconds.
6. Select Specific DTC. Enter DTC P0724.
Has the test run and passed?
System OK
Begin the
diagnosis again.
Go to
Step 1

7A1±54
TRANSMISSION CONTROL SYSTEM (4L30±E)

The PCM will illuminate the CHECK TRANS Lamp.

Turn force motor OFF.
Conditions For Clearing The DTC/CHECK
TRANS Lamp

The PCM will turn ªoffº the CHECK TRANS Lamp
after three consecutive ignition cycles without a
failure reported.

The DTC can be cleared from PCM memory by using
a scan tool.

The DTC can also be cleared from memory when the
vehicle has made 40 warmup cycles without a failure
reported.

The PCM will cancel the DTC Actions Taken items
when the fault conditions no longer exist and the
ignition is cycles ªoffº long enough to power down the
PCM.
Diagnostic Aids

Check for intermittent output speed sensor circuit
problems.

Check for possible incorrect calibration. (PCM part
No., tire specification, and rear axle ratio)
Test Description
The numbers below refer to the step numbers on the
diagnostic chart:
3. This step checks for possible low fluid level causing
slipping resulting in an undefined gear ratio.
4. This step checks for correct gear ratios for
commanded gears.
5. This step checks for low line pressure.
DTC P0730 Gear Error Without Input Speed
StepActionYe sNo
1Were you sent here from the ªOn±Board Diagnostic (OBD)
System Checkº?
Go to Step 2
Go to OBD
System Check
Refer to
Driveability and
Emission in
Engine section
2Visually inspect the transmission cooling system for fluid leaks.

Refer to
Chart 16: Possible Causes of Transmission Fluid
Leaks of Mechanical/Hydraulic Diagnosis Symptoms Index in
Automatic Transmission (4L30±E) section
Was condition found and corrected?Go to Step 7Go to Step 3
3Refer to Checking Transmission Fluid Level and Condition in
Automatic Transmission (4L30±E) section.
Has transmission fluid checking procedure been performed?
Go to Step 4
Go to Checking
Transmission
Fluid Level and
Condition in
Automatic
Transmission
(4L30±E) section
41. Install the scan tool.
2. Turn the ignition switch to the ªonº position.
3. Engine not running.
NOTE: Before clearing DTC(s) use the scan tool to record the
ªFailure Recordsº for reference, as data will be lost when the ªClear
Infoº function is used.
4. Record the Failure Record data.
5. Use the scan tool snapshot mode to record transmission gear
ratios.
6. Drive vehicle in transmission gear ranges L, 2, 3, and D with
the engine speed is greater than 3,500 rpm for 5.5 seconds.
7. Record each transmission gear.
1st:2.73 ± 2.99
2nd:1.54 ± 1.71
3rd:0.93 ± 1.05
4th:0.66 ± 0.78
Does commanded gear ratio match ranges as shown?
Refer to
Diagnostic AidsGo to Step 5

7A1±56
TRANSMISSION CONTROL SYSTEM (4L30±E)
DTC P0742 Torque Converter Clutch (TCC) System Stuck On
D07R200008
Circuit Description
The PCM energizes the TCC solenoid by creating an
ignition voltage on circuit BRN/BLU. When ignition
voltage is energized by the PCM, the TCC solenoid stops
converter signal oil from exhausting. This causes
converter signal oil pressure to increase and move the
TCC valve. The TCC solenoid will deenergize when the
PCM no longer provides ignition voltage. When the TCC
solenoid is deenergized, it will exhaust fluid and release
the TCC.
This DTC detects low torque converter slip when the TCC
is commanded ªoffº. This is a type ªBº DTC.
Conditions For Setting The DTC
The following conditions occur once per TCC cycle, three
consecutive times:

No TPS DTCs P0122 or P0123.

No OSS DTCs P0722 or P0723.

No TCC solenoid DTC P1860.

TP angle is greater than 20%.

Engine speed is greater than 500 rpm and less than
3,000 rpm.

Engine vacuum is between 0 and 70 kPa.

Commanded gear is not 1st.

Gear range is D4.

TCC is commanded ªoffº.

No TCC Stuck off DTC P1870.
TCC slip speed is between ±20 and 40 rpm for 2
seconds.

Vehicle speed is greater than 25 km/h (15 mph) and
less than 120 km/h (75 mph).

Speed ratio is greater than 0.9 and less than 2.0.
Action Taken When The DTC Sets

For lamp illuminate refer to DTC type definition (type
B).

Inhibit TCC engagement.
Conditions For Clearing The MIL/DTC

The PCM will turn off the MIL and CHECK TRANS
Lamp after three consecutive ignition cycles without a
failure reported.

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.

TRANSMISSION CONTROL SYSTEM (4L30±E)7A1±57
Diagnostic Aids

If the TCC is mechanically stuck ªonº with the parking
brake applied and any gear range selected, the TCC
fluid will mechanically apply the TCC, possibly
causing an engine stall.
Test Description
The number below refers to the step number on the
diagnostic chart:
3. This test checks the mechanical state of the TCC.
(When the PCM commands the TCC solenoid ªoffº,
the slip speed should increase).
DTC P0742 Torque Converter Clutch (TCC) System Stuck On
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
21. 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.
4. Using the scan tool, verify the ªTP Sensorº operation.
Are the ªTP Sensorº values within 0.6 ± 5.0 volts?
Go to Step 3
Go to Diagnostic
Aids
3Drive the vehicle in the D4 drive range in fourth gear under steady
acceleration, with a TP angle greater than 20%.
Does the scan tool display ªTCC Slip Speedº between ±30 and
+30 rpm, while the displayed TCC solenoid state is ªoffº?
Go to Step 4
Go to Diagnostic
Aids
4The TCC is mechanically stuck ªonº. Check the following items:

Clogged exhaust orifice in the TCC solenoid.

Converter clutch apply valve stuck in the apply position.

Misaligned or damaged valve body gasket.

Restricted release passage.
Was a problem found and corrected?
Go to Step 5Ð
51. After the repair is complete, use the scan tool to select ªDTCº,
then ªClear Infoº function and ensure the following conditions
are met:
TCC slip speed must be between 200 and 2,500 rpm for 4
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

7A1±58
TRANSMISSION CONTROL SYSTEM (4L30±E)
DTC P0748 Pressure Control Solenoid (PCS) (Force Motor) Circuit Electrical
D07R200009
Circuit Description
The PCS is a PCM±controlled device used to regulate
transmission line pressure. The PCM compares TPS
voltage, engine rpm, and other inputs to determine the
line pressure appropriate for a given load. The PCM will
regulate the pressure by applying a varying amperage to
the PCS. The applied amperage can vary from 70 to 1060
milliampere (mA), and is monitored by the PCM.
This DTC detects a continuous open or short to ground in
the PCS circuit or the PCS. This is a type ªCº DTC.
Conditions For Setting The DTC

Battery voltage is between 10 and 16 volts.

The PCM detects that the different between
commanded and actual current is 200 milliampere
(mA) for over 1 second.

Engine speed is greater than 300 rpm.
Action Taken When the DTC Sets

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

Maximum line pressure.

The PCM will illuminate the CHECK TRANS Lamp.

Turn Force Motor OFF (Durability).
Conditions For Clearing The DTC/CHECK
TRANS Lamp

The PCM will turn ªoffº the CHECK TRANS Lamp
after three consecutive ignition cycles without a
failure reported.
The DTC can be cleared from PCM history by using a
scan tool.

The DTC will be cleared from memory 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 at the transmission 4±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.
Test Description
The numbers below refer to the step numbers on the
diagnostic chart:
2. This test checks the ability of the PCM to command
the PCS.
3. This test checks the PCS and internal wiring harness
for incorrect resistance.