Isuzu Trooper (1998-2002 year). Manual - part 622

6E–136

4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P1405 (Flash DTC 37) 

EGR EVRV Circuit Open/Short

060RW135

Circuit Description

EGR EVRV Circuit has a common power source in
parallel with EGR, VSV, RPCV, and Intake Throttle Motor.
This may cause multiple DTCs. On such occasion, refer
to “Multiple ECM Information Sensor DTCs Set”.

Action Taken When the DTC Sets

D

The ECM 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

D

DTC P1405 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the ECM battery
feed.

Diagnostic Aids

An intermittent may be caused by a poor connection,
rubbed-through wire insulation or a wire broken inside the
insulation.  Check for:

D

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

D

Damaged harness – Inspect the wiring harness for
damage.

6E–137

4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS

DTC P1405 – EGR EVRV Circuit Open/Short

 

Step

Action

Value(s)

Yes

No

1

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

—

Go to 

Step 2

Go to 

OBD

System

Check

2

1. Review and record Failure Records information.
2. Clear DTC P1405.
3. Start the engine and idle for 1 minute.
4. Observe DTCs.

Is DTC P1405 set?

—

Go to 

Step 3

Refer to

Diagnostic

Aid

3

1. Ignition “OFF.”
2. Disconnect the EVRV.
3. Check for an open or a short to ground in the EVRV

circuit between the EVRV connector and the ECM
harness connector.

4. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to 

Step 4

4

Check the connections at the EVRV and replace the
terminals if necessary.

Did any terminals require replacement?

—

Verify repair

Go to 

Step 5

5

Check the connections at the ECM and replace the
terminals if necessary.

Did any terminals require replacement?

—

Verify repair 

Go to 

Step 6

6

Replace the EVRV.

Is the action complete?

—

Verify repair

Go to 

Step 7

7

Replace the ECM (Refer to the Data Programming in
Case of ECM change).

Is the action complete?

—

Verify repair

—

6E–138

4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P0406 (Flash DTC 26) 

 EGR Pressure Sensor High Voltage

 060RW134

Action Taken When the DTC Sets

D

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

D

The ECM 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

D

DTC P0404 can be cleared by using the scan tool
“Clear Info” function or by disconnecting the ECM
battery feed.

Diagnostic Aids

Check for the following conditions:

D

Poor connection or damaged harness – Inspect the
wiring harness for damage.

DTC P0406 – EGR Pressure Sensor High Voltage

 

Step

Action

Value(s)

Yes

No

1

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

—

Go to 

Step 2

Go to 

OBD

System

Check

2

Put the engine into an idling status.

Is the EGR pressure sensor voltage value displayed on
the Tech 2 above the specified value?

4 V

Go to 

Step 3

Go to 

Step 4

3

1. Turn off the ignition switch.
2. Remove the sensor connector connection.
3. Turn on the ignition switch “ON”.

Is the EGR pressure sensor voltage value displayed on
the Tech 2 below the specified value?

1 V

Go to 

Step 5

Go to 

Step 6

6E–139

4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS

DTC P0406 – EGR Pressure Sensor High Voltage

  (Cont'd)

Step

No

Yes

Value(s)

Action

4

Is the EGR pressure sensor voltage value displayed on
the Tech 2 below the specified value?

1 V

Refer to

Chart P0107

Refer to

Diagnostic

AidsandSymp

tom

Diagnosis

5

Connect the relay and solenoid checker
(5-8840-0386-0) to the battery voltage, then check the
sensor grounding circuit.

Does the checker lamp come on?

—

Go to 

Step 7

Go to 

Step 8

6

A voltage short circuit occurs in the MAP signal circuit
or this circuit is shorted with the 5V power circuit.
Repair the harness or Replace the ECM (Refer to the
Data Programming in Case of ECM change).

Is the action complete?

—

Verify repair

—

7

Replace the EGR pressure sensor hose or the EGR
pressure sensor.

Is the action complete?

—

Verify repair

—

8

Repair the harness for open ground circuit.

Is the action complete?

—

Verify repair

—