Isuzu D-Max / Isuzu Rodeo (TFR/TFS). Manual - part 174

6E–300

4JH1 ENGINE DRIVEABILITY AND EMISSIONS

Replace the ECM.
Is the action complete?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobiliser system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobiliser System-ECM replacement” for
the ECM/Immobiliser linking procedure.

—

Verify repair

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Step

Action

Value(s)

Yes

4JH1 ENGINE DRIVEABILITY AND EMISSIONS

6E–301

Diagnostic Trouble Code (DTC) P1690 (Symptom Code 8) (Flash Code 77)

Check Engine Lamp (MIL) Circuit Voltage High

Step

Action

Value(s)

Yes

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

—

Go to Step 2

Go to On Board

Diagnostic

(OBD) System

Check

1. Connect the Tech 2.

2. Review and record the failure information.

3. Select “F0: Read DTC Infor As Stored By ECU” in

“F0: Diagnostic Trouble Codes”.

Is the DTC P1690 (Symptom Code 8) stored as
“Present Failure”?

—

Go to Step 3

Refer to

Diagnostic Aids

and Go to Step

1. Using the Tech 2, ignition “On” and engine “Off”.

2. Select “F1: Clear DTC Information” in “F0:

Diagnostic Trouble Codes” with the Tech 2 and
clear the DTC information.

3. Operate the vehicle and monitor the “F0: Read

DTC Infor As Stored By ECU” in the “F0:
Diagnostic Trouble Codes”.

Was the DTC P1690 (Symptom Code 8) stored in this
ignition cycle?

—

Go to Step 4

Refer to

Diagnostic Aids

Is the ECM programmed with the latest software
release?
If not, download the latest software to the ECM using
the “SPS (Service Programming System)”.
Was the problem solved?

—

Verify repair

Go to Step 5

Substitute a known good ECM and recheck.
Was the problem solved?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobiliser system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobiliser System-ECM replacement” for
the ECM/Immobiliser linking procedure.

—

Go to Step 6

—

Verify repair

—

6E–302

4JH1 ENGINE DRIVEABILITY AND EMISSIONS

SYMPTOM DIAGNOSIS

PRELIMINARY CHECKS

Before using this section, perform the “On-Board
Diagnostic (OBD) System Check” and verify all of the
following items:

• The engine control module (ECM) and check engine

lamp (MIL=malfunction indicator lamp are operating
correctly.

• There are no Diagnostic Trouble Code(s) stored.

• Tech 2 data is within normal operating range. Refer to

Typical Scan Data Values.

• Verify the customer complaint and locate the correct

symptom in the table of contents. Perform the
procedure included in the symptom chart.

VISUAL/PHYSICAL CHECK

Several of the symptom procedures call for a careful
visual/physical check. This can lead to correcting a
problem without further checks and can save valuable
time. This check should include the following items:

• ECM grounds for cleanliness, tightness and proper

location.

• Vacuum hoses for splits, kinks, and proper

connection. Check thoroughly for any type of leak or
restriction.

• Air intake ducts for collapsed or damaged areas.

• Air leaks at throttle body mounting area, mass air flow

(MAF) sensor and intake manifold sealing surfaces.

• Wiring for proper connections, pinches and cuts.

INTERMITTENT

Important: An intermittent problem may or may not turn
on the check engine lamp (MIL=malfunction indicator
lamp) or store a Diagnostic Trouble Code. Do NOT use
the Diagnostic Trouble Code (DTC) charts for
intermittent problems.
The fault must be present to locate the problem.
Most intermittent problems are cased by faulty electrical
connections or wiring. Perform a careful visual/physical
check for the following conditions.

• Poor mating of the connector halves or a terminal not

fully seated in the connector (backed out).

• Improperly formed or damaged terminal.

• All connector terminals in the problem circuit should

be carefully checked for proper contact tension.

• Poor terminal-to-wire connection. This requires

removing the terminal form the connector body to
check.

• Check engine lamp (MIL=malfunction indicator lamp)

wire to ECM shorted to ground.

• Poor ECM grounds. Refer to the ECM wiring

diagrams.

Road test the vehicle with a Digital Multimeter
connected to a suspected circuit. An abnormal voltage
when the malfunction occurs is a good indication that
there is a fault in the circuit being monitored.
Using Tech 2 to help detect intermittent conditions. The
Tech 2 have several features that can be used to located
an intermittent condition. Use the following features to
find intermittent faults:

To check for loss of diagnostic code memory, disconnect
the MAF sensor and idle the engine until the check
engine lamp (MIL=malfunction indicator lamp) comes
on. Diagnostic Trouble Code P0100 should be stored
and kept in memory when the ignition is turned OFF.
If not, the ECM is faulty. When this test is completed,
make sure that you clear the Diagnostic Trouble Code
P0100 from memory.

An intermittent check engine lamp (MIL=malfunction
indicator lamp) with no stored Diagnostic Trouble Code
may be caused by the following:

• Check engine lamp (MIL=malfunction indicator lamp)

wire to ECM short to ground.

• Poor ECM grounds. Refer to the ECM wiring

diagrams.

Check for improper installation of electrical options such
as light, cellular phones, etc. Check all wires from ECM
to the ignition control module for poor connections.
Check for an open diode across the A/C compressor
clutch and check for other open diodes (refer to wiring
diagrams in Electrical Diagnosis).

If problem has not been found, refer to ECM connector
symptom tables.

• Check the “Broadcast Code” of the ECM, and

compare it with the latest Isuzu service bulletins and/
or Isuzu EEPROM reprogramming equipment to
determine if an update to the ECM's reprogrammable
memory has been released.

This identifies the contents of the reprogrammable
software and calibration contained in the ECM.
If the “Broadcast Code” is not the most current available,
it is advisable to reprogram the ECM's EEPROM
memory, which may either help identify a hard-to find
problem or may fix the problem.
The Service Programming System (SPS) will not allow
incorrect software programming or incorrect calibration
changes.

4JH1 ENGINE DRIVEABILITY AND EMISSIONS

6E–303

ENGINE CRANKS BUT WILL NOT RUN

DEFINITIONS: Engine cranks, but will not run. (The engine never start.)
NOTE: The vehicle with immobiliser system, this system may be activated. Check the immobiliser system diagnosis.

Step

Action

Value(s)

Yes

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

—

Go to Step 2

Go to On Board

Diagnostic

(OBD) System

Check

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

Was a visually/physical check performed?

—

Go to Step 4

Go to Visual /

physical Check

Is the fuel amount enough?

—

Go to Step 5

Add fuel to the

tank

Is the customer using the incorrect fuel type?

Diesel fuel

only

Replace with

diesel fuel

Go to Step 6

Check the “ECM” fuse (10A) and “Engine” fuse (15A).
If the fuse is burnt out, repair as necessary.
Was the problem found?

—

Verify repair

Go to Step 7

Visually/physically inspect for the following conditions.

• Restrict air intake system. Check for a restricted air

filter element, or foreign objects blocking the air
intake system

• Check for objects blocking or excessive deposits in

the throttle bore and on the throttle plate

• Check for a condition that causes a large vacuum

leak, such as an incorrectly installed or faulty
crankcase ventilation hose.

• Restrict air intake system at the turbocharger.

Check for objects blocking the turbocharger
compressor wheel or turbine shaft sticking.

If a problem is found, repair as necessary.
Was a problem found?

—

Verify repair

Go to Step 8

Check the ECM & PSG grounds to verify that they are
clean and tight. Refer to the ECM wiring diagrams.
Was a problem found?

—

Verify repair

Go to Step 9

1. Using the Tech 2, ignition “On” and engine “Off”.

2. Monitor the “Neutral Switch” in the data display.

Does the Tech 2 indicate correct “Neutral Switch”
status depending on any shift positions?
If a problem is found, repair as necessary.
Was the problem found?

—

Verify repair

Go to Step 10

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