Isuzu Trooper (1998-2002 year). Manual - part 478

6E–282

6VE1 3.5 ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P0404 EGR Open Stuck

D06R200075

Circuit Description

The powertrain control module (PCM) monitors the EGR
valve pintle position input to ensure that the valve
responds properly to commands from the PCM, and to
detect a fault if pintle position is different from
commanded position. If the PCM detects a pintle position
signal indicates more than 15 points different between
current and commanded and more than 15 seconds, the
PCM will set DTC P0404.

Conditions for Setting the DTC

The engine is running.

Ignition voltage is between 11 and 16 volts.

Intake Air Temp is more than 3

C (37.4

F).

Desire EGR position is less than 3%.

The difference between desired EGR and current EGR
is less than 3%.

Difference EGR pintle position between current and
commanded position becomes more than 15% and
last more than 15 seconds, and this condition meets
three times in a trip. Then it trigger, the PCM lights on.

Action Taken When the DTC Sets

The PCM will ON the MIL after second trip with
detected the fault.

The PCM will store conditions which were present
when the DTC was set as Freeze Frame and in 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 P0404 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

DTC P0404 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:

Excessive carbon deposit on EGR valve shaft may
cause EGR stuck open or unsmooth operation. Those
carbon deposit may occur by unusual port operation.
Clean up carbon may make smooth function of EGR
valve.

Poor connection or damaged harness – Inspect the
wiring harness for damage. If the harness appears to
be OK, observe the EGR actual position display on the
Tech 2 while moving connectors and wiring harnesses
related to EGR valve. A change in the display will
indicate the location of the fault.

6E–283

6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

DTC P0404 – EGR Open Stuck

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” info for DTC P0404

until the DTC P0404 test runs. Note the result.

Does the Tech 2 indicates DTC P0404 failed this
ignition?

—

Go to

Step 3

Check the

Procedure

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.

—

Verify repair

Is the action

complete?

1. Remove EGR valve from Engine.
2. Inspect EGR valve whether there is any excessive

carbon deposit on EGR shaft.

Was excessive carbon deposit on EGR valve shaft?

—

Go to

Step 6

Go to

Step 7

1. Clean up EGR valve shaft and inside of EGR valve.
2. Visually inspect damage of pintle and seat if is bent,

leakage may occur.

Was there any severe damage which affects function?

—

Go to

Step 8

Verify repair

Go to

Step 7

1. Reconnect.
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

Replace the EGR valve.

Does DTC P0404 still fail “DTC” test on the Tech 2?

—

Go to

Step 9

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–284

6VE1 3.5 ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P0405 EGR Low Voltage

D06R200075

Circuit Description

The powertrain control module (PCM) monitors the EGR
valve pintle position input to ensure that the valve
responds properly to command from the PCM. If current
pintle position voltage indicates less than 0.1 V and last
more than 10 seconds, then the PCM will set DTC P0405.

Conditions for Setting the DTC

Ignition voltage is between 11 and 16 volts.

Intake Air Temp is more than 3

C (37.4

F).

EGR pintle position is less than 2% and last more than
10 sec. Action taken when the DTC sets.

Action Taken When the DTC Sets

The PCM will ON the MIL after second trip with
detected the fault.

The PCM will store conditions which were present
when the DTC was set as Freeze Frame and in 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 P0402 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

DTC P0405 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:

6E–285

6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

DTC P0405 – EGR Low Voltage

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” info for DTC P0405

until the DTC P0405 test runs. Note the result.

Does the Tech 2 indicates DTC P0405 failed this
ignition?

—

Go to

Step 3

Check the

Procedure

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. Disconnect the EGR harness connector.
2. Ignition “ON”.
3. At the EGR valve, use a DVM to check the voltage

at the 5 volt reference wire (BLU/RED) and ground.

Did the DVM indicate the specified value?

4–6 V

Go to

Step 6

Go to

Step 7

1. Disconnect the EGR harness connector.
2. Measure resistance between terminal 5 volt

reference wire and ground.

Was resistance in range?

5–5.5 K

Go to

Step 10

Go to

Step 17

1. Ignition “ON”.
2. At the PCM connector, backprobe with a DVM at the

5 volt reference for the EGR valve.

Did the DVM indicate the specified value?

4–6 V

Go to

Step 8

Go to

Step 9

Repair the open 5 volt reference circuit.

Is the action complete?

—

Verify repair

—

Repair the damaged sensor ground wire.

Is the action complete?

—

Verify repair

—

1. Disconnect the EGR harness
2. Use an ohmmeter to measure between the pintle

position pin and the sensor ground pin on the EGR
valve.

NOTE: J-35616 Connector Test Adapter Kit may be
useful for gaining access to the recessed pins on the
valve.

Was the ohmmeter reading approximately equal to the
specified value?

1 to 1.25 K

Go to

Step 13

Go to

Step 17

1. Ignition “ON”.
2. Backprobe with a DVM to measure voltage at EGR

valve pintle position pin and sensor ground pin.

Was voltage in range?

Less than

0.1 V

Go to

Step 17

Go to

Step 12

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