Isuzu Trooper (1998-2002 year). Manual - part 635

6E–188

4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS

Dieseling, Run-On Symptom

 

Step

Action

Value(s)

Yes

No

1

DEFINITION:
Engine continues to run after key is turned “OFF,” but
runs very rough.  If engine runs smooth, check ignition
switch and adjustment.

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

—

Go to 

Step 2

Go to 

OBD

System

Check

2

1. Perform a bulletin search.
2. If a bulletin that addresses the symptom is found,

correct the condition as instructed in the bulletin.

Was a bulletin found that addresses the symptom?

—

Verify repair

Go to 

Step 3

3

Was a visual/physical check performed?

—

Go to 

Step 4

Go to 

Visual/

Physical

Check

4

1. Check for a short between B+ and any of the ignition

feed circuits.

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

Was a problem found?

—

Verify repair

Go to 

Step 5

5

1. Review all diagnostic procedures within this table.
2. If all procedures have been completed and no

malfunctions have been found, review/inspect the
following:

D

Visual/physical inspection

D

Tech 2 data

D

Freeze Frame data/Failure Records butter

D

All electrical connections within a suspected
circuit and/or system

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

Was a problem found?

—

Verify repair

Contact

Technical

Assistance

6E–189

4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS

Cuts Out, Symptom

 

Step

Action

Value(s)

Yes

No

1

DEFINITION:
Steady pulsation or jerking that follows engine speed;
usually more pronounced as engine load increases.

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

—

Go to 

Step 2

Go to 

OBD

System

Check

2

1. Perform a bulletin search.
2. If a bulletin that addresses the symptom is found,

correct the condition as instructed in the bulletin.

Was a bulletin found that addresses the symptom?

—

Go to 

Step 7

Go to 

Step 3

3

Was a visual/physical check performed?

—

Go to 

Step 4

Go to 

Visual/

Physical

Check

4

1. Check the ECM grounds for clearness, tightness

and proper routing.  Refer to the ECM wiring
diagrams in 

Electrical Diagnosis.

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

Was a problem found?

—

Verify repair

Go to 

Step  5

5

1. Check for incorrect idle speed.  Ensure that the

following conditions are present:

D

The engine is fully warm.

D

The accessories are “off.”

2. Using a Tech 2, monitor the AP position.

Is the AP position within the specified values?

0%

Go to 

Step 6

Go to 

Step 7

6

1. Visually/physically inspect for the following

conditions:

D

Restricted air intake system.  Check for a
possible collapsed air intake duct, restricted
air filter element, or foreign objects blocking
the air intake system.

D

Check the Throttle body.

D

Large vacuum leak.  Check for a condition that
causes a large vacuum leak, such as an
incorrectly installed or faulty VSV or brake
booster hose disconnected .

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

Was a problem found?

—

Verify repair

Go to 

Step 7

7

Using a Tech 2, monitor the AP angle with the engine
idling.

Is the AP angle at the specified value and steady?

0%

Go to 

Step 8

Refer to 

DTC

P0123 for

further

diagnosis

8

1. Check the transmission range switch circuit.  Use a

Tech 2 and be sure the Tech 2 indicates that the
vehicle is in drive with the gear selector in drive or
overdrive.

2. If a problem is found, diagnose and repair the

transmission range switch as necessary.

Was a problem found?

—

Verify repair

Go to 

Step 9

6E–190

4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS

Cuts Out, Symptom

  (Cont'd)

Step

No

Yes

Value(s)

Action

9

1. Injector Test

Operate the each injector by Tech 2 with the
ignition “ON” and check if the working noise
confirm.

2. If a problem is found, check the harness or replace

the injector.

Is the action complete?

—

Verify repair

Go to 

Step 10

10

1. Check the following engine mechanical items.

Refer to 

Engine Mechanical for diagnosis

procedures:

D

Low compression

D

Sticking or leaking valves

D

Worn camshaft lobe(s)

D

Camshaft drive belt slipped or stripped

D

Incorrect valve timing

D

Broken valve springs

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

Was a problem found?

—

Verify repair

Go to 

Step 11

11

1. Check for faulty motor mounts.  Refer to 

Engine

Mechanical for inspection of mounts.

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

Was a problem found?

—

Verify repair

Go to 

Step 12

12

1. Review all diagnostic procedures within this table.
2. If all procedures have been completed and no

malfunctions have been found, review/inspect the
following:

D

Visual/physical inspection

D

Tech 2 data

D

Freeze Frame data/Failure Records butter

D

All electrical connections within a suspected
circuit and/or system

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

Was a problem found?

—

Verify repair

Contact

Technical

Assistance

6E–191

4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS

Starter Motor Doesn’t Rotate

 

Step

Action

Value(s)

Yes

No

1

DEFINITION:
As starter motor doesn’t rotate, engine is not cranked.

1. Perform a bulletin search.
2. If a bulletin that addresses the symptom is found,

correct the condition as instructed in the bulletin.

Was the bulletin found?

—

Verify repair

Go to 

Step 2

2

Was a visual/physical check performed?

—

Go to 

Step 3

Go to 

Visual/

Physical

Check

3

1. Check battery cord terminal for looseness & poor

contact due to corrosion.

2. Check battery voltage.
3. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to 

Step 4

4

1. Check fan belt for looseness & damage.
2. If a problem is found, adjust or replace as

necessary.

Was a problem found?

—

Verify repair

Go to 

Step  5

5

1. Check fuse bull link for disconnection & short.
2. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to 

Step 6

6

1. Check generator for mount & damage (Refer to

Engine Mechanical).

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

Was a problem found?

—

Verify repair

Go to 

Step 7

7

1. Check starter SW and starter relay for looseness

and damage.

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

Was a problem found?

—

Verify repair

Go to 

Step 8 

8

1. Check starter motor for mount and damage. (Refer

to 

Engine Mechanical)

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

Was a problem found?

—

Verify repair

Go to 

Step 9

9

1. Review all diagnostic procedures within this table.
2. If all procedures have been completed and no

malfunctions have been found, review/inspect the
following:

D

Visual/physical inspection

D

Tech 2 data

D

Freeze Frame data/Failure Records butter

D

All electrical connections within a suspected
circuit and/or system

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

Was a problem found?

—

Verify repair

Contact

Technical

Assistance