Isuzu Amigo / Axiom / Trooper / Rodeo / VehiCross. Manual - part 932

7A1–48 TRANSMISSION CONTROL SYSTEM (4L30–E)

DTC P0723 Automatic Transmission Output Speed Sensor (OSS) Intermittent

D07RY00016

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 low output speed when there is a high
engine speed in a drive gear range. This is a type “B”
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 seconds.

NORAW-NORAWLAST < 200 rpm for 2 seconds.

NORAW Latest raw data of output shaft speed.

NORAWLAST Filtered pervious 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 illumination 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 trips 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 failure
reported.

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

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

Step

Action

Yes

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

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

Check for the most current and/or incorrect calibration.

Is the calibration current?

Go to Step 16

Go to Step 4

1. Turn the ignition “off”.
2. Disconnect the J2 (RED) PCM connector.
3. Using the J39200 DVOM, measure the resistance between

harness connector terminals J2–22 and J2–55.

Is the reading 3,000 ohms?

Go to Step 5

Go to Step 6

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

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

1. Reconnect the J2 (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

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

Replace the OSS.

Is the replacement complete?

Go to Step 17

—

Was the reading in step 7 less than 4.0 volts?

Go to Step 12

Go to Step 11

Was the reading in Step 7 greater than 5.1 volts?

Go to Step 15

—

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

7A1–50 TRANSMISSION CONTROL SYSTEM (4L30–E)

DTC P0723 Automatic Transmission Output Speed Sensor (OSS) Intermittent (Cont’d)

Step

Yes

Action

Repair the open in circuit WHT.

Is the repair complete?

Go to Step 17

—

Check circuit RED for a short to ground or open.

Was a problem found and corrected?

Go to Step 17

Go to Step 16

Repair the short to B+ in circuit RED.

Is the repair complete?

Go to Step 17

—

Replace the PCM. Refer to Powertrain Control Module (PCM) in
Automatic Transmission (4L30–E) section.

Is the replacement complete?

Go to Step 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)

7A1–51

DTC P0724 Brake Switch Circuit High (Stuck Off)

D07RY00012

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

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

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.

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