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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 No
1 Did you perform the Diagnostic System Check -
Immobilizer Controls? —
Go to Step 2 Go to Diagnostic
System Check - Immobilizer
Controls
2 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.
1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. 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
3 Does the scan tool communicate with the ECM?
—
Go to Step 4 Go to Diagnostic
System Check -
Engine Controls
4 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
5 Does the scan tool communicate with the ICU?
—Go to Step 6 Go to Lost
Communication with The Immobilizer
Control Unit (ICU)
BACK TO CHAPTER INDEX TO MODEL INDEX
ISUZU KB P190 2007
Page 5865 of 6020
11A-14 IMMOBILIZER CONTROL SYSTEM (4JK1/4JJ1/HFV6)
6Test 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
7 1. Inspect for an intermittent, for poor
connections and for corrosion at the data link
connector (DLC) (pins 6 and 14 of B-58)
2. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 17 Go to Step 8
8 Notice:
If no data recording module (DRM) is
installed, skip to Step 9.
1. Turn OFF the ignition.
2. Disconnect the DRM C-139 harness connector.
3. Turn ON the ignition, with the engine OFF.
4. 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
9 1. Turn OFF the ignition.
2. Reconnect the DRM C-139 harness connector if disconnected.
3. Disconnect the ECM J1 (E-90) and J2 (C-58) harness connectors.
4. Turn ON the ignition, with the engine OFF.
5. 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
10 Notice:
If no AISIN automatic transmission is
installed, skip to Step 11.
1. Turn OFF the ignition.
2. Reconnect the ECM J1 (E-90) and J2 (C-58) harness connectors.
3. Disconnect the TCM C-94 and C-95 harness connectors.
4. Turn ON the ignition, with the engine OFF.
5. 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 No
BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007
Page 5867 of 6020
11A-16 IMMOBILIZER CONTROL SYSTEM (4JK1/4JJ1/HFV6)
2Important:
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.
1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. 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
3 Does the scan tool communicate with the PIM?
—
Go to Step 4 Go to Diagnostic
System Check -
Powertrain Interface
Module
4 Does the scan tool communicate with the ECM?
—Go to Step 5 Go to Diagnostic
System Check -
Engine Controls
5 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
6 Does the scan tool communicate with the ICU?
—Go to Step 7 Go to Lost
Communication with The Immobilizer
Control Unit (ICU)
7 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 20 System OK
8 1. Inspect for an intermittent, for poor
connections and for corrosion at the data link
connector (DLC) (pins 6 and 14 of B-58).
2. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 20 Go to Step 9
9 1. Turn OFF the ignition.
2. Disconnect the ECM C-56 and E-60 harness connectors.
3. Turn ON the ignition, with the engine OFF.
4. 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 No
BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007
Page 5868 of 6020
IMMOBILIZER CONTROL SYSTEM (4JK1/4JJ1/HFV6) 11A-17
10Notice:
If no automatic transmission is installed,
skip to Step 11.
1. Turn OFF the ignition.
2. Reconnect the ECM C-56 and E-90 harness connectors.
3. Disconnect the TCM C-96 harness connector.
4. Turn ON the ignition, with the engine OFF.
5. Attempt to communicate with the PIM and ICU.
Does the scan tool communicate with the PIM and
ICU? —
Go to Step 13 Go to Step 11
11 1. Turn OFF the ignition.
2. Reconnect the ECM C-56 and E-90 harness connectors if disconnected.
3. Reconnect the TCM C-96 harness connector if disconnected.
4. Disconnect the PIM B-96 and B-97 harness connectors.
5. Turn ON the ignition, with the engine OFF.
6. Attempt to communicate with the ICU.
Does the scan tool communicate with the ICU? —
Go to Step 14 Go to Step 12
12 1. Turn OFF the ignition.
2. Reconnect the PIM B-96 and B-97 harness connectors.
3. Disconnect the ICU B-109 harness connector.
4. Turn ON the ignition, with the engine OFF.
5. Attempt to communicate with the ECM, TCM and PIM.
Does the scan tool communicate with the ECM,
TCM and PIM? —
Go to Step 19 Go to Step 15
13 1. Test the CAN Low and High circuits between
the ECM (pins 23 and 55 of C-56) and the
TCM (pins 6 and 7 of C-96) for the following
conditions:
• A short to ground
• A short to battery or ignition voltage
• A short circuit each other
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 20 Go to Step 17
14 1. Test the CAN Low and High circuits between
the PIM (pins 7 and 9 of B-97) and the TCM
(pins 37 and 38 of C-96) or ECM (pins 23 and
55 of C-56) for the following conditions:
• A short to ground
• A short to battery or ignition voltage
• A short circuit each other
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 20 Go to Step 18
Step
Action Value(s)Yes No
BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007