Isuzu Trooper (2000 year). Manual - part 407

7A1–42 TRANSMISSION CONTROL SYSTEM (4L30–E)

DTC P0719 Brake Switch Circuit Low (Stuck On)

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 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.

DTC P0719 Brake Switch Circuit Low (Stuck On)

Step

Action

Yes

Was the Powertrain On–Board Diagnostic (OBD) System Check
performed?

Go to Step 2

Go to Powertrain

OBD System

Check

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.
6. Connect a test lamp from cavity B13–2 of the brake switch

connector to a known good ground.

Is the test lamp ON?

Go to Step 3

Go to Step 4

Install a J 36169–A Fused Jumper Wire from terminal B13–3 to
terminal B13–2 of the brake switch connector.

Did the TCC Brake Switch status change from Open to Closed?

Go to Step 7

Go to Step 9

1. Remove the fuse C–4 (15A).
2. Inspect the fuse for an open.

Is the fuse open?

Go to Step 5

Go to Step 8

Inspect circuit BLU/WHT for a short to ground condition. Repair
the circuit if necessary.

Did you find a short to ground condition?

Go to Step 11

Go to Step 6

Inspect circuit ORN for a short to ground condition. Repair the
circuit if necessary.

Did you find a short to ground condition?

Go to Step 11

Go to Step 10

Replace the brake switch.

Is the replacement complete?

Go to Step 11

—

Inspect circuit BLU/WHT for an open condition. Repair the circuit
if necessary.

Did you find and correct an open condition?

Go to Step 11

—

Inspect circuit ORN for an open.

Did you find an open condition?

Go to Step 11

Go to Step 10

7A1–44 TRANSMISSION CONTROL SYSTEM (4L30–E)

DTC P0719 Brake Switch Circuit Low (Stuck On) (Cont’d)

Step

Yes

Action

Replace the PCM.

Is the replacement complete?

Go to Step 11

—

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. Do not depress the brake pedal.
5. Verify that the TCC Brake Switch status indicates “Closed” (12

volts) for 2 seconds.

6. Select Specific DTC. Enter DTC P0719.

Has the test run and passed?

System OK

Begin the

diagnosis again.

Go to Step 1

TRANSMISSION CONTROL SYSTEM (4L30–E)

7A1–45

DTC P0722 Automatic Transmission Output Speed Sensor (OSS) Low Input

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

No MAP DTCs P0107 or P0108, P0106, P1106,
P1107.

No TPS DTCs P0122 or P0123.

Not in Park or Neutral.

TP angle is greater than 10%.

Engine vacuum is between 0 and 70kPa.

Engine speed is between 3,000 and 7,000 rpm.

Transmission output speed is less than 0 rpm.

All conditions met for 5 seconds.

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 “off”
long enough to power down the PCM.

Diagnostic Aids

An OSS DTC P0722 will set when no output speed is
at detected at start off.

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.

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