Isuzu Trooper (1998-2002 year). Service manual — part 786
TRANSMISSION CONTROL SYSTEM (4L30–E)
7A1–53
D
For lamp illumination refer to DTC type definition
(type B).
Conditions For Clearing The MIL/DTC
D
The PCM will turn off the MIL and CHECK TRANS
Lamp after three consecutive trips without a failure
reported.
D
The DTC can be cleared from the PCM history by
using a scan tool.
D
The DTC will be cleared from history when the vehicle
has achieved 40 warmup cycles without failure
reported.
D
The PCM will cancel the DTC default actions when
the fault no longer exists and the ignition is cycled “off”
long enough to power down the PCM.
Diagnostic Aids
D
A OSS DTC P0723 will set when output speed has
been detected and is lost.
D
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.
D
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.
DTC P0723 Automatic Transmission Output Speed Sensor (OSS) Intermittent
Step
Action
Yes
No
1
Were you sent here from the “Powertrain On–Board Diagnostic
(OBD) System Check”?
Go to Step 2
Go to OBD
System Check
Refer to
Driveability and
Emissions in
Engine section
2
1. Install the scan tool.
2. With the engine “off”, turn the ignition switch “on”.
NOTE: Before clearing DTC(s), use the scan tool to record “Freeze
Frame” and “Failure Records” for reference, as data will be lost
when the “Clear Info” function is used.
3. Record the DTC “Freeze Frame” and “Failure Records”.
4. Raise the drive wheels.
5. Start the engine.
6. Place the transmission in any drive range.
With the drive wheels rotating, does the “Trans Output Speed”
increase with the drive wheel speed?
Go to Diagnostic
Aids
Go to Step 3
3
Check for the most current and/or incorrect calibration.
Is the calibration current?
Go to Step 16
Go to Step 4
4
1. Turn the ignition “off”.
2. Disconnect the S (RED) PCM connector.
3. Using the J39200 DVOM, measure the resistance between
harness connector terminals S–22 and S–55.
Is the reading 3,000 ohms?
Go to Step 5
Go to Step 6
5
1. Select AC volts.
2. Rotate the rear wheels, ensuring the driveshaft is turning.
Is the voltage greater than 0.5 volts?
Go to Step 7
Go to Step 8
6
Inspect circuits RED and WHT for a poor connection or an open
circuit.
Was a problem found?
Go to Step 17
Go to Step 8
7A1–54 TRANSMISSION CONTROL SYSTEM (4L30–E)
DTC P0723 Automatic Transmission Output Speed Sensor (OSS) Intermittent (Cont’d)
Step
No
Yes
Action
7
1. Reconnect the S (RED) PCM connector.
2. Disconnect the OSS harness from the OSS.
3. With the engine “off”, turn the ignition “on”.
4. Using the J 39200 DVOM, measure the voltage at the OSS
harness connector terminals M15–2 and M15–1.
Is the reading between 4.0 to 5.1 volts?
Go to Step 16
Go to Step 10
8
1. Remove the OSS.
2. Check the output shaft speed sensor rotor for damage or
misalignment. Refer to Speed Sensor (Extension Housing) in
Automatic Transmission (4L30–E) section.
Was a problem found?
Go to Step 17
Go to Step 9
9
Replace the OSS.
Is the replacement complete?
Go to Step 17
—
10
Was the reading in step 7 less than 4.0 volts?
Go to Step 12
Go to Step 11
11
Was the reading in Step 7 greater than 5.1 volts?
Go to Step 15
—
12
Using the J 39200 DVOM to chassis ground, measure the voltage
on circuit RED.
Is the reading between 4.0 to 5.1 volts?
Go to Step 13
Go to Step 14
13
Repair the open in circuit WHT.
Is the repair complete?
Go to Step 17
—
14
Check circuit RED for a short to ground or open.
Was a problem found and corrected?
Go to Step 17
Go to Step 16
15
Repair the short to B+ in circuit RED.
Is the repair complete?
Go to Step 17
—
16
Replace the PCM. Refer to Powertrain Control Module (PCM) in
Automatic Transmission (4L30–E) section.
Is the replacement complete?
Go to Step 17
—
17
1. After the repair is complete, use the scan tool to select “DTC”,
then “Clear Info” function and operate the vehicle under the
following conditions:
Transmission output speed is greater than 101 rpm for 3
seconds.
2. Review the scan tool “DTC Info”.
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)
7A1–55
DTC P0724 Brake Switch Circuit High (Stuck Off)
LHD
D07R200047
RHD
D07R200048
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 ORN 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
D
No OSS Assy. DTCs P0722 or P0723.
D
The PCM detects a closed brake switch circuit (12
volts) without changing and the following events
occur seven consecutive times:
D
The vehicle speed is greater than 32 km/h (20 mph)
for 4 seconds;
D
then the vehicle speed is between 8–32 km/h (5–20
mph) for 4 seconds;
D
then the vehicle speed is less than 8 km/h (5 mph).
7A1–56 TRANSMISSION CONTROL SYSTEM (4L30–E)
Action Taken When The DTC Sets
D
The PCM does not illuminate the Malfunction
Indicator Lamp (MIL).
D
DTC P0724 stores in PCM history.
Conditions For Clearing The DTC
D
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.
D
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
D
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.
D
When diagnosing for a possible intermittent short or
open condition, move the wiring harness while
observing test equipment for a change.
D
Check customer driving habits and/or unusual traffic
conditions (i.e. stop and go, expressway).
D
Check brake switch for proper mounting and
adjustment.
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)
Step
Action
Yes
No
1
Was the Powertrain On–Board Diagnostic (OBD) System Check
performed?
Go to Step 2
Go to Powertrain
OBD System
Check
2
1. Install the scan tool.
2. With the engine “off,” turn the ignition switch to the “on”
position.
NOTE: Before clearing the DTC(s), use the scan tool in order to
record the “Failure Records” for reference. Using the “Clear Info”
function will erase the stored “Failure Records” from the PCM.
3. Record the DTC Failure Records, then clear the DTC(s).
4. Select “TCC Brake Switch” on the scan tool.
5. Disconnect the brake switch connector from the brake switch.
Did the TCC brake switch status change from “Closed” to “Open”?
Go to Step 3
Go to Step 4
3
Replace the brake switch.
Is the replacement complete?
Go to Step 6
—
4
Inspect circuit ORN for a short to B+ condition. Repair the circuit if
necessary.
Did you find a short to B+ condition?
Go to Step 6
Go to Step 5
5
Replace the PCM.
Is the replacement complete?
Go to Step 6
—
6
In order to verify your repair, perform the following procedure:
1. Select DTC.
2. Select “Clear Info”.
3. With the engine “off” turn the ignition switch to the “on” position.
4. Apply the brake pedal.
5. Verify that the TCC brake switch status indicates “Open” (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
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