Content .. 477 478 479 480 ..

Isuzu Trooper (1998-2002 year). Manual - part 479

6E–286

6VE1 3.5 ENGINE DRIVEABILITY AND EMISSIONS

DTC P0405 – EGR Low Voltage

(Cont'd)

Step

Yes

Value(s)

Action

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

sensor ground pin and pintle position pin.

Was voltage in range?

Less than

0.1 V

Go to

Step 13

Go to

Step 18

1. Ignition “OFF”.
2. Disconnect the EGR harness.
3. Check short circuit between EGR pintle position

circuit and EGR ground circuit.

Was any short circuit?

—

Go to

Step 14

Go to

Step 18

Locate and repair the short to ground in the pintle
position circuit

Is the action complete?

—

Verify repair

—

1. Ignition “OFF”.
2. Disconnect the PCM.
3. Ignition “ON”.
4. Measure the voltage between the EGR pintle

position circuit and ground.

Is the measured voltage near the specified value?

Less than

0.1 V

Go to

Step 17

Go to

Step 16

Check for a short circuit between other wires and the
pintle position circuit

Is there any short circuit?

—

Repair short

circuit and then

Verify repair

Go to

Step 17

Replace the EGR valve.

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

—

Go to

Step 18

Verify repair

Examine the PCM pin and terminal connection.

Was there a damaged terminal?

—

Go to

Step 4

Go to

Step 19

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–287

6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P0406 EGR High 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 more than 4.8 V and last
more than 10 seconds, then the PCM will set DTC P0406.

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 more than 99% and last more
than 10 sec.

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 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:

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–288

6VE1 3.5 ENGINE DRIVEABILITY AND EMISSIONS

DTC P0406 – EGR High 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 P0406

until the DTC P0406 test runs. Note the result.

Does the Tech 2 indicates DTC P0406 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

Is the action

complete?

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).

Did the DVM indicate the specified value?

4–6 V

Go to

Step 8

Go to

Step 6

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 7

Go to

Step 16

Repair the open 5 volt reference circuit

Is the action complete?

—

Verify repair

—

1. Ignition “OFF”
2. Disconnect the EGR harness.
3. Use a DVM to check for an resistance between 5 V

reference and Sensor Ground at EGR sensor
terminals.

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

Was the measured resistance in range?

5 to 5 K

Go to

Step 9

Go to

Step 15

1. Ignition “OFF”.
2. Disconnect the EGR harness.
3. Use a DVM to check for an resistance between

Sensor Ground and Signal Wire at EGR sensor
terminal.

Is there an open circuit?

—

Go to

Step 15

Go to

Step 10

1. Ignition “OFF”.
2. Disconnect the EGR harness at PCM connector.
3. Use a DVM to check for shorted wire between S37

and F53.

Is there a shorted wire?

—

Go to

Step 14

Go to

Step 11

6E–289

6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

DTC P0406 – EGR High Voltage

(Cont'd)

Step

Yes

Value(s)

Action

1. Ignition “ON”.
2. Use a DVM to backprobe at terminal Connector of

EGR valve for voltage.

Was measured voltage more than 4.8 V?

more than

4.8 V

Go to

Step 12

Go to

Step 12

1. Ignition “ON”.
2. Stay the EGR harness connected.
3. Check voltage by backprobing at PCM S37

terminal.

Was voltage more than 4.8 V?

4.8 V

Go to

Step 16

Go to

Step 13

1. Locate short circuit at EGR harness between

BLU/RED to GRY/RED or GRY/RED to YEL,
BLU/RED.

2. Replace EGR harness.

Is the action complete?

—

Verify repair

—

Replace EGR harness.

Is the action complete?

—

Verify repair

—

Replace the EGR valve.

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

—

Go to

Step 16

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

—

Content .. 477 478 479 480 ..