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Isuzu Trooper (2000 year). Manual - part 334

6E–465

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

DTC P1404 – EGR Stuck Closed

Step

Action

Value(s)

Yes

Was the “On-Board Diagnostic (OBD) System Check”
performed?

—

Go to

Step 2

Go to

OBD

System

Check

1. Ignition “ON,” engine “OFF”, review and record

Tech 2 Failure Records Data.

2. Operate the vehicle within Failure Records

conditions as noted.

3. Using a Tech 2, monitor “DTC inf. for DTC P1404

until the DTC P1404 test runs. Note the result.

Does the Tech 2 indicates DTC P1404 failed this
ignition?

—

Go to

Step 3

Refer to

Diagnostic

Aids

1. Disconnect the EGR valve harness connector.
2. Inspect the EGR valve and connectors for damaged

pin or terminals.

Were there any damaged pins or terminals?

—

Go to

Step 4

Go to

Step 5

Repair the damaged pin or terminal.

Is the action complete?

—

Verify repair

—

1. Remove EGR valve from Engine.
2. Inspect EGR valve for any excessive carbon

deposit on EGR shaft.

3. Inspect for any foreign material inside of EGR valve.

Was excessive carbon deposit on EGR valve shaft
and/or foreign material in EGR valve ?

—

Go to

Step 6

Go to

Step 7

1. Clean up EGR valve shaft and inside of EGR valve.
2. Remove foreign material from EGR valve.
3. Visually inspect damage of pintle and seat to see if it

is bent. If damaged leakage may occur.

Was there any severe damage which affects function?

—

Go to

Step 8

Verify repair

Go to

Step 7

1. Install the EGR valve.
2. Ignition “OFF”.
3. Install the Tech 2.
4. Run the engine at idle.
5. On the Tech 2, select EGR Control Test.
6. Use the “UP” arrow to increase the EGR from 0% to

40%.

Did EGR work properly?

—

Go to

Step 8

1. Reset the learned zero EGR valve position.
2. Repeat step 7.

Did EGR work properly?

—

Verify repair

Go to

Step 9

6E–466

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

DTC P1404 – EGR Stuck Closed

(Cont'd)

Step

Yes

Value(s)

Action

Replace the EGR valve.

Does DTC P1404 still fail “DTC” test on the Tech 2?

—

Go to

Step 10

Verify repair

Replace the PCM.

IMPORTANT: The replacement PCM must be
programmed. Refer to

On-Vehicle Service in

Powertrain Control Module and Sensors for
procedures.

And also refer to latest Service Bulletin.

Check to see if the Latest software is released or not.
And then Down Load the LATEST PROGRAMMED
SOFTWARE to the replacement PCM.

Is the action complete?

—

Verify repair

—

6E–467

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P1441 EVAP System Flow During Non-Purge

D06RY00128

Circuit Description

Canister purge is controlled by a solenoid valve that
allows manifold vacuum to purge the canister. The
powertrain control module (PCM) supplies a ground to
energize the solenoid valve (purge “ON”). The EVAP
purge solenoid control is pulse-width modulated (PWM)
or turned “ON” and “OFF” several times a second. The
duty cycle (pulse width) is determined by engine
operating conditions including load, throttle position,
coolant temperature and ambient temperature. The duty
cycle is calculated by the PCM and the output is
commanded when the appropriate conditions have been
met.
The EVAP purge vacuum switch is a normally closed
switch positioned in the purge line between the canister
and to EVAP purge solenoid. The EVAP purge vacuum
switch will open when vacuum increases to greater than 5
inches of water in the purge line. The PCM monitors the
EVAP purge vacuum switch signal to determine if the
evaporative emission control system is working properly.
If the switch is open (purge flow detected) when the PCM
is not commanding the EVAP purge solenoid “ON,” DTC
P1441 will be set.

Conditions for Setting the DTC

No active ECT sensor, IAT sensor, MAP sensor,
vacuum switch, or TP sensor DTCs set.

BARO reading is above 85 kPa.

Engine coolant temperature is below 70

C (158

F).

Start-up intake air temperature (IAT) and start-up
engine coolant temperature (ECT) are both above 5

(41

F).

The difference between start-up ECT and start-up IAT
is less than 25

C (45

F).

TP sensor indicates a throttle position above 12%.

Battery voltage is between 11.5 volts and 16 volts.

Engine speed is between 800 and 6,000 RPM.

Canister purge duty cycle is below 3%.

Canister purge vacuum switch is open, which results
in the PCM signal voltage (from the vacuum switch
input) being approximately 12 volts.

All conditions are present for at least 3 seconds.

Action Taken When the DTC Sets

The PCM will illuminate the malfunction indicator lamp
(MIL) after the second consecutive trip in which the
fault is detected.

The PCM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.

Conditions for Clearing the MIL/DTC

The PCM will turn the MIL “OFF” on the third
consecutive trip cycle during which the diagnostic has
been run and the fault condition is no longer present.

A history DTC P1441 will clear after 40 consecutive
warm–up cycles have occurred without a fault.

6E–468

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

DTC P1441 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the PCM battery
feed.

Diagnostic Aids

Check for the following conditions:

Poor connection at PCM – Inspect harness connectors
for backed-out terminals, improper mating, broken
locks, improperly formed or damaged terminals, and
poor terminal-to-wire connection.

Damaged harness – Inspect the wring harness for
damage. If the harness appears to be OK, observe the
EVAP vacuum switch display on the Tech 2 while
moving connectors and wiring harnesses related to the
sensor. A change in the display will indicate the
location of the fault.

Reviewing the Failure Records vehicle mileage since the
diagnostic test last failed may help determine how often
the condition that caused the DTC to be set occurs. This
may assist in diagnosing the condition.

Test Description

Number(s) below refer to the step number(s) on the
Diagnostic Chart.
2. The canister purge vacuum switch is normally closed

when no vacuum (purge) is present. With the
ignition “ON” and the engine “OFF,” there shouldn’t
be any vacuum (purge) present in the EVAP
system.

3. Determines if the PCM is able to control the EVAP

purge solenoid valve.

4. Determines if the DTC will set under the conditions

present when the DTC was originally stored. If not,
the fault is intermittent.

5. Checks for a grounded EVAP purge solenoid driver

circuit, a faulty EVAP vacuum switch, or a leaking
EVAP purge solenoid valve.

DTC P1441 – EVAP System Flow During Non-Purge

Step

Action

Value(s)

Yes

Was the “On-Board Diagnostic (OBD) System Check”
performed?

—

Go to

Step 2

Go to

OBD

System

Check

1. Ignition “OFF.”
2. Remove the fuel filler cap.
3. Ignition “ON.”
4. Observe “Fuel Tank Pressure” on the Tech 2.

Is “Fuel Tank Pressure” at the specified value?

1.51V

Go to

Step 3

Go to

DTC

P0452 or

P0453

1. Re-install the fuel filler cap.
2. Using the Tech 2, command the EVAP Vent

Solenoid Valve “ON” (Closed).

3. Disconnect the canister side rubber hose end that

hose is connected between the Purge Solenoid
Valve and Canister.

IMPORTANT: Before continuing with the diagnosis,
zero the EVAP pressure/purge cart J41413 (refer to the
tool operating instructions).
And them monitor the fuel tank inner pressure using the
Tech 2.

Does the fuel tank pressure remain the specified
value?

1.52 - 1.60V

Go to

Step 4

Go to

Step 6

1. Disconnect the EVAP pressure/purge cart J41413,

and then plug the hose end.

2. Disconnect the rubber hose end of engine vacuum

source side, (the hose connected between Purge
Solenoid Valve and engine).

3. Connect the vacuum hand pump to this rubber hose

end.

4. Then apply the -15 in H2O vacuum by the vacuum

pump.

5. Monitor the fuel tank inner pressure using the Tech

Does the fuel tank inner pressure hold the specified
value?

1.47 - 1.51V

Go to

Step 6

Go to

Step 5

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