Isuzu Trooper (1998-2002 year). Manual - part 637

6E–196

4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS

QOS System Doesn’t Work

 

Step

Action

Value(s)

Yes

No

1

Was OBD System check performed?

—

Go to 

Step 2

Go to 

OBD

System

Check

2

Check glawplug indicator light. If bulb is broken,
replace.

Was a problem found?

—

Verify repair

Go to 

Step 3

3

1. Connect a circuit tester between glawplug & engine

ground.

2. With ignition on and engine off, check if the glaw

indicator and circuit tester indicate power voltage
for 9 to 13 sec. If not indicated, repair terminal & wire
harness.

Was repair needed?

—

Verify repair

Go to 

Step 4

4

1. Connect a circuit tester between glawplug and

engine ground.

2. With engine on, check if voltage continues for 180

sec. If not, inspect and repair glaw relay.

Was repair needed?

—

Verify repair

Go to 

Step 5

5

1. Remove the glawplug, and if damaged, replace.
2. Check glawplug resistance.

Was resistance as specified?

0.8 – 1

W

Go to 

Step 7

Go to 

Step 6

6

Replace glawplug.

Was measure completed?

—

Verify repair

Go to 

Step 7

7

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–197

4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS

Much Black Smoke in Exhaust Gas

 

Step

Action

Value(s)

Yes

No

1

DEFINITION:
In road tests, much black smoke is mixed.

Was OBD System check performed?

—

Go to 

Step 2

Go to 

OBD

System

Check

2

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

correct the condition as instructed in the bulletin.

Was a bulletin found?

—

Verify repair

Go to 

Step 3

3

1. Check if a correct fuel is used.
2. If a problem is found, change fuel.

Was a problem found?

—

Verify repair

Go to 

Step 4

4

1. Check air cleaner element for clogging.
2. If a problem is found, repair or replace as

necessary.

Was a problem found?

—

Verify repair

Go to 

Step 5

5

1. Connect Tech 2 to the vehicle.
2. Monitor data list to check injector function.
3. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to 

Step 6

6

1. Connect Tech 2 to the vehicle.
2. Monitor RPCV test to check rpcv function.
3. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to 

Step 7

7

1. Check valve clearance.
2. If a problem is found, adjust as necessary.

Was a problem found?

—

Verify repair

Go to 

Step 8

8

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

malfunctions have been found, review/inspect the
following:

D

Visual/physical check

D

Tech 2 data list

D

Freeze Frame data

D

All electrical connections in suspected circuits
& systems

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

Was a problem found?

—

Verify repair

Contact

Technical

Assistance

6E–198

4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS

Excess Engine Oil Consumption

 

Step

Action

Value(s)

Yes

No

1

DEFINITION:
Oil consumption measured in road tests is higher than
expected.

Was OBD System check performed?

—

Go to 

Step 2

Go to 

OBD

System

Check

2

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

correct the condition as instructed in the bulletin.

Was a bulletin found?

—

Verify repair

Go to 

Step 3

3

1. Check if a correct engine oil is used.
2. If a problem is found, change engine oil.

Was a problem found?

—

Verify repair

Go to 

Step 4

4

1. Check oil pipe connections for leakage.
2. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to 

Step 5

5

1. Check oil seals and gaskets for leakage.
2. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to 

Step 6

6

1. Connect Tech 2 to the vehicle.
2. Perform RPCV test to check its function.
3. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to 

Step 7

7

1. Check piston ring for damage & groove wear.
2. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to 

Step 8

8

1. Check valve stem, valve guide and oil controller for

wear.

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

Was a problem found?

—

Verify repair

Go to 

Step 9

9

1. Check camshaft carrier & cylinder head gaskets for

blow-by.

2. If a problem is found, repair or replace as

necessary.

Was a problem found?

—

Verify repair

Go to 

Step 10

10

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

malfunctions have been found, review/inspect the
following:

D

Visual/physical check

D

Tech 2 data list

D

Freeze Frame data

D

All electrical connections in suspected circuits
& systems

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

Was a problem found?

—

Verify repair

Contact

Technical

Assistance

6E–199

4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS

Default Matrix Table

Service Procedure Default Strategy

A referral strategy has been established to assist the
technician with additional information when the cause of

the failure cannot be determined.  If no problem is found
after performing diagnostics, then refer to the default
matrix table for further diagnostic information.

Default Matrix Table

Strategy Based Diagnostic Charts

Initial Diagnosis

Default Section(s)

On-Board Diagnostic (OBD) System
Check

Vehicle does not enter diagnostics.

Chassis Electrical

On-Board Diagnostic (OBD) System
Check

Vehicle enters diagnostics and
communicates with the Tech 2.  MIL is
“ON” in diagnostics.  Engine does not
start and run.

HEUI System Check

On-Board Diagnostic (OBD) System
Check

Engine starts and runs, no ECM codes
set.  Customer complains of vibration.

—

On-Board Diagnostic (OBD) System
Check

Engine starts and runs, no ECM codes
set.  Customer complains of harsh or
soft shift, poor performance, delayed or
no engagement into drive or reverse,
transmission fluid leak, transmission
noise or vibration, or improper TCC
operation.

Automatic Transmission

ECM Power and Ground Check

On-Board Diagnostic (OBD) System
Check.

Chassis Electrical

ECM Power and Ground Check

On-Board Diagnostic (OBD) System
Check. ECM power and ground circuits
OK. Data link voltage incorrect.

Chassis Electrical

On-Board Diagnostic (OBD) System
Check

Engine starts and runs, no ECM codes
set.  Customer complains of harsh or
soft shift, poor performance, delayed or
no engagement into drive or reverse,
transmission fluid leak, transmission
noise or vibration, or improper TCC
operation.

Automatic Transmission

Symptoms

Initial Diagnosis

Default Section(s)

Intermittents

1. On-board diagnostic (OBD)

system check.

2. Careful visual/physical inspections.

Chassis Electrical

Hard Starts

1. OBD system check.
2. Sensors (ECT, MAP, EGR, AP) ;

output chart.

3. Fuel system electrical test, fuel

system diagnosis.

4. Injector system.

Engine Mechanical, Injector
System Check, Exhaust System
Diagnosis

Surges and/or Chuggles

1. OBD system check.
2. Fuel system diagnosis.
3. Injector system.

Calibration ID “Broadcast”
/Service Bulletins, Ignition
System Check, Generator
Output, Exhaust System
Diagnosis

Lack of Power, Sluggish or Spongy

1. OBD system check.
2. Fuel system diagnosis.
3. Injector system.

Refer to 

Exhaust System in

Engine Exhaust, TCC
Operation, Calibration
ID/Service Bulletins