Keyword Device - Isuzu N 2008 Series Workshop Manual

1A-50 Engine Control System (4JJ1)
Scan Tool Does Not Communicate with
Keyword Device
Specification)
Circuit Description
The ECM, the transmission control module (TCM), the
hill start aid (HSA) control unit, the supplemental
restraint system (SRS) control unit and the immobilizer
control unit (ICU) communicates with the scan tool over
the Keyword serial data link. However, the ECM, the
electric hydraulic control unit (EHCU), the TCM, the
data recording module (DRM) and the instrument panel
(IP) cluster communicate with each other over the
controller area network (CAN) link. The CAN link is not
used for communication with the scan tool and is
shared only among each module.
Circuit/ System Testing Scan Tool Does Not Communicate with Keyword Device (Except Euro 4
Specification)
Step
Did you perform the Diagnostic System Check -
1 Engine Controls?
1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. Attempt to communicate with the listed control
modules.
• ECM
• Transmission
(Smoother only)
2
• Hill start aid (HSA) control unit
(If so equipped)
• Supplemental restraint system (SRS)
control unit (If so equipped)
• Immobilizer control unit (ICU)
(If so equipped)
Does the scan tool communicate with any of the
listed control modules?
Does the scan tool communicate with the ECM?
3
Notice: If no Smoother transmission is installed,
skip to Step 5.
4
Does the scan tool communicate with the TCM?
Notice: If no HSA system is installed, skip to Step
6.
5
Does the scan tool communicate with the HSA
control unit?
Notice: If no airbag system is installed, skip to Step
7.
6
Does the scan tool communicate with the SRS
control unit?
(Except Euro
Action
control module (TCM)
Diagnostic Aids
4
The following conditions will cause a loss of Keyword
serial data communication between the TCM, SRS
control unit and HSA control unit or between the scan
tool any control module:
• A Keyword serial data circuit open
• A Keyword serial data circuit shorted to ground
• A Keyword serial data circuit shorted to voltage
• An internal condition within a module or connector
on the Keyword serial data circuit, that causes a
short to voltage or ground to the Keyword serial
data circuit.
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Value(s)
—
—
—
—
—
—
Yes
Go to Diagnostic
System Check -
Go to Step 2 Engine Controls
Go to Step 3 Go to Step 9
Go to Lost
Communication with
The Engine Control
Go to Step 4 Module (ECM)
Go to Diagnostic
System Check -
Transmission
Controls in Section
5A Transmission
Go to Step 5 Control System
Go to Diagnostic
System Check -
HSA Controls in
Go to Step 6 Section 4E HSA
Go to Diagnostic
System Check -
SRS Controls in
Section 8C SRS
Go to Step 7 Control System
No