Isuzu N 2008 Series Workshop Manual page 54

Step
Notice: If no immobilizer system is installed, skip to
Step 8.
7
Does the scan tool communicate with the ICU?
Test the Keyword serial data circuit for an
intermittently short to ground or intermittently short
to voltage. Then, test the Keyword serial data
circuit for an intermittently open (based on which
8
control module did not communicate) at the
connection in the circuit.
Did you find and correct the condition?
1. Inspect for an intermittent, for a poor
connection and for corrosion at the data link
connector (DLC) (pin 7 of B31).
9
2. Repair the connection(s) as necessary.
Did you find and correct the condition?
1. Turn OFF the ignition.
2. Disconnect the ECM E12 and J14 harness
connectors.
3. Turn ON the ignition, with the engine OFF.
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4. Attempt to communicate with the TCM, HSA
control unit, SRS control unit and ICU.
Does the scan tool communicate with the TCM,
HSA control unit, SRS control unit and ICU?
Notice: If no Smoother transmission is installed,
skip to Step 12.
1. Turn OFF the ignition,
2. Reconnect the ECM E12 and J14 harness
connectors.
3. Disconnect the TCM B109, B110, B111 and
11
B112 harness connectors.
4. Turn ON the ignition, with the engine OFF.
5. Attempt to communicate with the ECM, SRS
control unit and ICU.
Does the scan tool communicate with the ECM,
SRS control unit and ICU?
Notice: If no HSA system is installed, skip to Step
13.
1. Turn OFF the ignition.
2. Reconnect the ECM E12 and J14 harness
connectors if disconnected.
3. Disconnect the HSA control unit B14 harness
12
connector.
4. Turn ON the ignition, with the engine OFF.
5. Attempt to communicate with the ECM, SRS
control unit and ICU.
Does the scan tool communicate with the ECM,
SRS control unit and ICU?
Action
Engine Control System (4JJ1)
Value(s) Yes
—
Go to Step 8
—
Go to Step 21
—
Go to Step 21
—
Go to Step 16
—
Go to Step 17
—
Go to Step 18
1A-51
No
Go to Diagnostic
System Check -
Immobilizer
Controls in Section
9I Security and Lock
System OK
Go to Step 10
Go to Step 11
Go to Step 12
Go to Step 13