Isuzu Trooper (1998-2002 year). Manual - part 600

6E–48

4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS

Malfunction Indicator Lamp (MIL) “ON” Steady

 

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. Ignition “OFF,” disconnect ECM.
2. Ignition “ON,” observe the MIL (CHECK ENGINE

lamp).

Is the MIL “ON?”

—

Go to 

Step 3

Go to 

Step 5

3

1. Ignition “OFF,” disconnect the instrument panel

cluster.

2. Check the MIL driver circuit between the ECM and

the instrument panel cluster for a short to ground.

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

Was the MIL driver circuit shorted to ground?

—

Go to 

OBD

System

Check

Go to 

Step 4

4

Replace the instrument panel cluster.

Is the action complete?

—

Go to 

OBD

System

Check

—

5

1. Ignition “OFF,” reconnect the ECM.
2. Ignition “ON,” reprogram the ECM. Refer to

On-Vehicle Service  in Engine Control Module and
Sensor for procedures.

3. Using the Tech 2 output controls function, select

MIL dash lamp control and command the MIL
“OFF.”

Did the MIL turn “OFF?”

—

Go to 

OBD

System

Check

Go to 

Step 6

6

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

Is the action complete?

—

Go to 

OBD

System

Check

—

6E–49

4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS

Engine Cranks But Will Not Run

Circuit Description

In this type of injector system, the Engine Control Module
(ECM) triggers the correct driver inside the injector, which
then triggers the correct injector based on the 57X signal
received from the crankshaft position sensor (CKP).
During crank, the ECM monitors the CKP 57X signal.  The
CKP signal is used to determine which cylinder will fire
first.  After the CKP 57X signal has been processed by the
ECM, it will command all four injectors to allow a priming
shot of fuel for all the cylinders.  After the priming, the
injectors are left “OFF” during the next four 57X reference
pulses from the CKP.  This allows each cylinder a chance
to use the fuel from the priming shot.  During this waiting
period, a camshaft position (CMP) signal pulse will have
been received by the ECM.  The CMP signal allows the
ECM to operate the injectors sequentially based on
camshaft position.  If the camshaft position signal is not
present at start-up, the ECM will begin sequential fuel
delivery with a 1-in-4 chance that fuel delivery is correct.
The engine will run without a CMP signal, but will set a
DTC code.

Diagnostic Aids

An intermittent problem may be caused by a poor
connection, rubbed-through wire insulation or a wire

broken inside the insulation.  Check for the following
items:

D

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

D

Faulty engine coolant temperature sensor – Using a
Tech 2, compare engine coolant temperature with
manifold air temperature on a completely cool engine.

Test Description

Number(s) below refer to the step number(s) on the
Diagnostic Chart.
4. An obvious cause of low fuel pressure would be an

empty fuel tank.

5. The engine will easily start and run if a few injectors

are disabled.  It is not necessary to test all injectors
at this time since this step is only a test to verify that
all of the injectors have not been disabled by fuel
contamination.

8.If there is an open or shorted driver circuit, DTCs

0201-0204 should be set.

Engine Cranks But Will Not Run

 

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

Check the 15 A injector fuse, the 15 A engine device
fuse, and the 15A ECM fuse.

Was a fuse blown?

—

Go to 

Step 3

Go to 

Step 4

3

Check for a short to ground and replace the fuse.

Is the action complete?

—

Verify repair

—

4

Is fuel tank empty?

—

Fill the fuel

tank

Go to 

Step 5

5

Is the right fuel using?

—

Go to 

Step 6

Replace the

fuel

6

Is the right engine oil using?

—

Go to 

Step 7

Replace the

engine oil

7

Using the Tech–2.

Is DTC P0192 or P0193 set? (Check rail pressure
system)

—

Go to 

DTC

P0192 or

DTC P0193

Go to 

Step 8

8

Using the Tech–2.

Is DTC P0201 – P0204 set? (Check inject circuit fault)

—

Go to 

DTC

P0201 –

P0204

Go to 

Step 9

9

Using the Tech–2.

Is DTC P1657 set? (Check ECM Main relay)

—

Go to 

DTC

P1657

Go to 

Step 10

6E–50

4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS

Engine Cranks But Will Not Run

  (Cont'd)

Step

No

Yes

Value(s)

Action

10

Refer to 

Engine Mechanical Diagnosis to diagnose the

following conditions:

D

Faulty camshaft drive belts

D

Leaking or sticky valves or rings

D

Excessive valve deposits

D

Weak valve springs

D

Incorrect valve timing

D

Leaking head gasket

Is the action complete?

—

Verify repair

Go to 

Step 11

11

Observe the “Engine Speed” data display on the Tech 2
while cranking the engine.

Is the engine RPM indicated?  (If the Tech 2 is normally
powered from the cigarette lighter socket, and if the
Tech 2 display goes blank while cranking the engine, it
will be necessary to power the Tech 2 directly from the
vehicle battery.)

—

Go to 

Step 12

Go to 

Step 17

12

1. At the ECM (female) side of the connector

mentioned in step, connect a test light between the
ignition + terminal and one of the injector driver
circuits at the same connector.

2. Ignition “ON.”
3. Observe the test light, and repeat the test for each

injector driver circuit by oscilloscope.

Did the test light stay on when checking any of the 4
injector driver circuits?

—

Go to 

Step 13

Go to 

Step 15

13

1. Ignition “OFF,” disconnect the ECM.
2. Ignition “ON,” observe the test light.

Is the test light “ON?”

—

Go to 

Step 14

Go to 

Step 16

14

Locate and repair the short to ground in the injector
driver circuit.

Is the action complete?

—

Verify repair

—

15

Check for an open injector driver circuit.

Was a problem found?

—

Verify repair

Go to 

Step 16

16

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

Is the action complete?

—

Verify repair

—

17

1. Raise the vehicle and disconnect the CKP sensor

harness.

2. Ignition “ON.”
3. With a test light to ground, probe the harness

ignition feed terminal.

Did the light illuminate?

—

Go to 

Step 19

Go to 

Step 18

18

Check the ignition feed wire between the sensor and
the ECM for a short to ground or open circuit.

Is the action complete?

—

Verify repair

—

6E–51

4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS

Engine Cranks But Will Not Run

  (Cont'd)

Step

No

Yes

Value(s)

Action

19

1. Ignition “ON.”
2. At the CKP harness connector, connect a test light

between the ignition and ground terminals.

Did the light illuminate?

—

Go to 

Step 21

Go to 

Step 20

20

Check the sensor ground circuit for an open or short to
voltage.

Is the action complete?

—

Verify repair

—

21

Check the signal circuit between the sensor and the
ECM for a short to ground, short to voltage, or an open.

Was a problem found?

—

Verify repair

Go to 

Step 22

22

Replace the CKP sensor.

Is the action complete?

—

Verify repair

Go to 

Step 16