Isuzu engine C22NE / 22LE / 20LE. Manual - part 104

DRIVEABILITY AND EMISSIONS  6E1-245

KEY

TRANSPONDER

ENCRYPT

ENCRYPT

TECH-2

CARTRIDGE

ENCRYPT

BATTERY

IGN''ON''

IGN''ON''

IGN''ON''

GND

BATTERY

INJECTION:STOP

IGNITION:STOP

GND

CPU

ECM

ANTENNA COIL

RELAY

(STARTER CUT)

VEHICLE
SPEED SENSOR

IMMOBILIZER
CONTROL UNIT

VSS IN

OTHER SYSTEM

DIAGNOSIS

VEHICLE SPEED SENSOR LINE
VSS OUT

CHECK
ENGINE
LAMP
(MIL)

ENGINE
MANAGEMENT
SYSTEM

DIAGNOSIS

DLC

DIAGNOSTIC TROUBLE CODE (DTC) (Flash DTC=85)

SECURITY CODE & SECURITY KEY NOT PROGRAMMED

Circuit Description

The ECM decides whether that is an abnomality in the

immobilizer control system. DTC 85 is recorded by the

ECM when security code & secret key not

programmed.

Condition for Setting the DTC

• Security code & secret key not programmed.

Action Taken When the DTC Sets

• Flashing the MIL.
• The engine does not start.

Condition for Clearing the MIL/DTC

• Use clear DTC information with Tech2. (Refer to

the immobilizer workshop manual.) (ISUZU TF

Immobilizer system)

Diagnostic Aids

Check for the following conditions:
• Poor connection at ECM and Immobilizer-Inspect

harness connectors for backed out terminals,

improper mating, broken locks, improperly formed

or damaged terminals, and poor terminal to wire

connection.

• Damaged harness?Inspect the wiring harness for

damage, If the harness appears to be OK,

disconnect the ECM and Immobilizer, turn the

ignition "ON" and observe a voltmeter connected to

the suspect driver circuit at the ECM and

Immobilizer harnass connector while moving

connectors and wiring harnesses relates to the MIL.

A change in voltage will indicate the location of the

fault.

6E1-246  DRIVEABILITY AND EMISSIONS

DTC (Flash DTC=85)

Security Code & Secret Key Not Programmed

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

Using the Tech2 system selection menu, select Body

function.

Does the Tech2 indicate DTC B****?

-

Refer to

"Immobilizer

workshop

manual"

Go to Step 3

3

IMPORTANT: The replacement ECM must be

programmed. Refer to On-Vehicle Service in Engine

Control Module and Sensors for procedures and

Immobilizer system workshop manual.

And also refer to latest Service Bulletin.

Check to see if the Latest software is released or not.

And then Down Load the LATEST PROGRAMMED

SOFTWARE to the replacement ECM.

Is the action complete?

-

Go to Step 4

-

4

Does the Tech2 indicate DTC 85?

-

Go to Step 3

Verify repair.

DRIVEABILITY AND EMISSIONS  6E1-247

KEY

TRANSPONDER

ENCRYPT

ENCRYPT

TECH-2

CARTRIDGE

ENCRYPT

BATTERY

IGN''ON''

IGN''ON''

IGN''ON''

GND

BATTERY

INJECTION:STOP

IGNITION:STOP

GND

CPU

ECM

ANTENNA COIL

RELAY

(STARTER CUT)

VEHICLE
SPEED SENSOR

IMMOBILIZER
CONTROL UNIT

VSS IN

OTHER SYSTEM

DIAGNOSIS

VEHICLE SPEED SENSOR LINE
VSS OUT

CHECK
ENGINE
LAMP
(MIL)

ENGINE
MANAGEMENT
SYSTEM

DIAGNOSIS

DLC

DIAGNOSTIC TROUBLE CODE (DTC) (Flash DTC=86)

RECEIVED INCORRECT SECURITY CODE

Circuit Description

The ECM decides whether that is an abnomality in the

immobilizer control system. DTC 86 is recorded by the

ECM when received incorrect security code.

Condition for Setting the DTC

• Received incorrect security code.

Action Taken When the DTC Sets

• Flashing the MIL.
• The engine does not start.

In case replacement ECM, Action Taken

When the DTC Sets

• Flashing the MIL.

Condition for Clearing the MIL/DTC

• Use clear DTC information with Tech2. (Refer to

the immobilizer workshop manual.) (ISUZU TF

Immobilizer system)

Diagnostic Aids

Check for the following conditions:
• Poor connection at ECM and Immobilizer-Inspect

harness connectors for backed out terminals,

improper mating, broken locks, improperly formed

or damaged terminals, and poor terminal to wire

connection.

• Damaged harness?Inspect the wiring harness for

damage, If the harness appears to be OK,

disconnect the ECM and Immobilizer, turn the

ignition "ON" and observe a voltmeter connected to

the suspect driver circuit at the ECM and

Immobilizer harnass connector while moving

connectors and wiring harnesses relates to the MIL.

A change in voltage will indicate the location of the

fault.

6E1-248  DRIVEABILITY AND EMISSIONS

DTC (Flash DTC=86)

Received Incorrect Security Code

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

Recheck the security code.

Is the action complete?

-

Verify repair

-