Isuzu KB P190. Manual - part 1466

IMMOBILIZER CONTROL SYSTEM (4JK1/4JJ1/HFV6) 11A-13

Scan Tool Does Not Communicate with CAN Device

Circuit Description

The engine control module (ECM), transmission control
module (TCM) (AISIN A/T only) and ICU all
communicate with the scan tool over the controller area
network (CAN) link. The ECM, TCM, ICU and the data
recording module (DRM) communicate with each other
over the same CAN link. (4JK1/ 4JJ1)
The ECM, TCM, powertrain interface module (PIM) and
ICU all communicate with the scan tool over the CAN
link. (HFV6)

Diagnostic Aids

The following conditions will cause a loss of CAN serial
data communication between the ECM, TCM and PIM
or between the scan tool and any control module:

• A CAN serial data circuit open

• A CAN serial data circuit shorted to ground

• A CAN serial data circuit shorted to voltage

• An internal condition within a module or connector

on the CAN serial data circuit, that causes a short
to voltage or ground to the CAN serial data circuit

Schematic Reference: Immobilizer Controls
Schematics

Connector End View Reference: ICU Connector End
View

Circuit/ System Testing Scan Tool Does Not Communicate with CAN Device (4JK1/ 4JJ1)

Step

Action

Value(s)

Yes

Did you perform the Diagnostic System Check -
Immobilizer Controls?

—

Go to Step 2

Go to Diagnostic

System Check -

Immobilizer

Controls

Important: Make sure the CANdi module is not
malfunctioning. When functioning properly, the
CANdi module LED will be flashing. In the event of
a problem, the LED will be continually illuminated
or not illuminated.

Install a scan tool.

Turn ON the ignition, with the engine OFF.

Attempt to establish communication with the
listed control modules.

• Immobilizer Control Unit (ICU)

• Engine control module (ECM)

• Transmission control module (TCM)

(AISIN A/T only)

Does the scan tool communicate with any of the
listed control modules?

—

Go to Step 3

Go to Step 7

Does the scan tool communicate with the ECM?

—

Go to Step 4

Go to Diagnostic

System Check -
Engine Controls

Notice: If no AISIN automatic transmission is
installed, skip to Step 5.

Does the scan tool communicate with the TCM?

—

Go to Step 5

Go to Diagnostic

System Check -

Transmission

Controls

Does the scan tool communicate with the ICU?

—

Go to Step 6

Go to Lost

Communication with

The Immobilizer

Control Unit (ICU)

11A-14 IMMOBILIZER CONTROL SYSTEM (4JK1/4JJ1/HFV6)

Test the CAN Low and High serial data circuit for an
intermittently short to ground, intermittently short to
voltage or short circuit each other. Then, test the
CAN Low and High serial data circuit for an
intermittently open (based on which control module
did not communicate) at the connection in the
circuit.

Did you find and correct the condition?

—

Go to Step 17

System OK

Inspect for an intermittent, for poor
connections and for corrosion at the data link
connector (DLC) (pins 6 and 14 of B-58)

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 17

Go to Step 8

Notice: If no data recording module (DRM) is
installed, skip to Step 9.

Turn OFF the ignition.

Disconnect the DRM C-139 harness
connector.

Turn ON the ignition, with the engine OFF.

Attempt to communicate with the ECM, TCM
and ICU.

Does the scan tool communicate with the ECM,
TCM and ICU?

—

Go to Step 13

Go to Step 9

Turn OFF the ignition.

Reconnect the DRM C-139 harness connector
if disconnected.

Disconnect the ECM J1 (E-90) and J2 (C-58)
harness connectors.

Turn ON the ignition, with the engine OFF.

Attempt to communicate with the TCM and
ICU.

Does the scan tool communicate with the TCM and
ICU?

—

Go to Step 14

Go to Step 10

Notice: If no AISIN automatic transmission is
installed, skip to Step 11.

Turn OFF the ignition.

Reconnect the ECM J1 (E-90) and J2 (C-58)
harness connectors.

Disconnect the TCM C-94 and C-95 harness
connectors.

Turn ON the ignition, with the engine OFF.

Attempt to communicate with the ECM and
ICU.

Does the scan tool communicate with the ECM and
ICU?

—

Go to Step 15

Go to Step 11

Step

Action

Value(s)

Yes

IMMOBILIZER CONTROL SYSTEM (4JK1/4JJ1/HFV6) 11A-15

Circuit/ System Testing Scan Tool Does Not Communicate with CAN Device (HFV6)

Turn OFF the ignition.

Reconnect the ECM J1 (E-90) and J2 (C-58)
harness connectors if disconnected.

Reconnect the TCM C-94 and C-95 harness
connectors if disconnected.

Disconnect the ICU B-109 harness connector.

Turn ON the ignition, with the engine OFF.

Attempt to communicate with the ECM and
TCM.

Does the scan tool communicate with the ECM and
TCM?

—

Go to Step 16

Go to Step 12

Repair the open circuit, short to ground, short to
voltage or short circuit each other on the CAN Low
or High serial data circuit between the DLC and
ECM, TCM, ICU or DRM.

Did you complete the repair?

—

Go to Step 17

—

Replace the DRM. Refer to DRM Replacement.

Did you complete the replacement?

—

Go to Step 17

—

Important: Replacement ECM must be
programmed and learned.
Replace the ECM. Refer to ECM Replacement.

Did you complete the replacement?

—

Go to Step 17

—

Important: Replacement TCM must be
programmed.
Replace the TCM. Refer to TCM Replacement.

Did you complete the replacement?

—

Go to Step 17

—

Important: Replacement ICU must be
programmed.
Replace the ICU. Refer to ICU Replacement.

Did you complete the replacement?

—

Go to Step 17

—

Attempt to establish communication with the ECM,
TCM and ICU.

Does the scan tool communicate with the ECM,
TCM and ICU?

—

System OK

Go to Step 2

Step

Action

Value(s)

Yes

Did you perform the Diagnostic System Check -
Immobilizer Controls?

—

Go to Step 2

Go to Diagnostic

System Check -

Immobilizer

Controls

Step

Action

Value(s)

Yes

11A-16 IMMOBILIZER CONTROL SYSTEM (4JK1/4JJ1/HFV6)

Important: Make sure the CANdi module is not
malfunctioning. When functioning properly, the
CANdi module LED will be flashing. In the event of
a problem, the LED will be continually illuminated
or not illuminated.

Install a scan tool.

Turn ON the ignition, with the engine OFF.

Attempt to establish communication with the
listed control modules.

• Immobilizer Control Unit (ICU)

• Engine control module (ECM)

• Transmission control module (TCM)

• Powertrain Interface module (PIM)

Does the scan tool communicate with any of the
listed control modules?

—

Go to Step 3

Go to Step 8

Does the scan tool communicate with the PIM?

—

Go to Step 4

Go to Diagnostic

System Check -

Powertrain Interface

Module

Does the scan tool communicate with the ECM?

—

Go to Step 5

Go to Diagnostic

System Check -
Engine Controls

Notice: If no automatic transmission is installed,
skip to Step 6.

Does the scan tool communicate with the TCM?

—

Go to Step 6

Go to Diagnostic

System Check -

Transmission

Controls

Does the scan tool communicate with the ICU?

—

Go to Step 7

Go to Lost

Communication with

The Immobilizer

Control Unit (ICU)

Did you find and correct the condition?

—

Go to Step 20

System OK

Inspect for an intermittent, for poor
connections and for corrosion at the data link
connector (DLC) (pins 6 and 14 of B-58).

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 20

Go to Step 9

Turn OFF the ignition.

Disconnect the ECM C-56 and E-60 harness
connectors.

Turn ON the ignition, with the engine OFF.

Attempt to communicate with the TCM, PIM
and ICU.

Does the scan tool communicate with the TCM,
PIM and ICU?

—

Go to Step 16

Go to Step 10

Step

Action

Value(s)

Yes

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