Content .. 326 327 328 329 ..

Isuzu Trooper (1998-2002 year). Service manual - part 328

6E–225

ENGINE DRIVEABILITY AND EMISSIONS

DTC P0402 – EGR Pintle Crank Open Error

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 Tech 2, monitor “Specific DTC” info for DTC

P0402 until the DTC P0402 test runs. Note the
result.

Does Tech 2 indicates DTC P0402 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 whether there is any foreign

material between seat and pintle.

Was any foreign material in EGR valve?

—

Go to

Step 6

Go to

Step 7

1. Remove EGR valve foreign material from EGR

valve and clean up inside.

2. Visually inspect damage of pintle and seat, which

leakage may occur.

Was there any severe damage which affects function?

—

Go to

Step 7

Verify repair

Go to

Step 8

1. Reconnect.
2. Ignition “OFF”.
3. Install Tech 2.
4. Run the engine at idle.
5. On Tech-II, select special function for EGR.
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 P0402 still fail “DTC” test on Tech 2?

—

Go to

Step 9

Verify repair

Replace the EGR valve.

Is the action complete?

—

Verify repair

—

6E–226

ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P0404 EGR Open Stuck

D06RW106

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

Ignition voltage is between 11 and 16 volts.

Intake Air temp is more than 3

Desire EGR position is more than 0.

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 illuminate the malfunction indicator lamp
(MIL) as soon as failure detected after consecutive 2nd
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 Failure
Records data.

Conditions for Clearing the MIL/DTC

DTC P0404 can be cleared by using 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
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–227

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 Tech 2, monitor “Specific DTC” info for DTC

P0404 until the DTC P0404 test runs. Note the
result.

Does Tech 2 indicates DTC P0404 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.

—

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 0n 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 whether

there 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 Tech 2.
4. Run the engine at idle.
5. On Tech 2, select F3:Misc. Test; F2:EGR.
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 Tech 2?

—

Go to

Step 9

Verify repair

Replace the PCM.

IMPORTANT: The replacement PCM must be
programmed. Refer to

UBS 98model year Immobilizer

Workshop Manual.

Is the action complete?

—

Verify repair

—

6E–228

ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P0405 EGR Low Voltage

D06RW106

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.

EGR pintle position output voltage is less than 0.1 volt
and last more than 10 sec. Action taken when the DTC
sets.

Action Taken When the DTC Sets

The PCM will illuminate the malfunction indicator lamp
(MIL) as soon as failure detected.

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

DTC P0405 can be cleared by using Tech 2 “Clear Info”
function or by disconnecting the PCM battery feed.

Diagnostic Aids

Check for the following conditions:

Content .. 326 327 328 329 ..