Isuzu 4JA1 Workshop Manual page 455

Step
5 1. Turn OFF the ignition.
2. Disconnect the neutral switch harness connector.
3. Turn ON the ignition, with the engine OFF.
4. Observe the Neutral Switch parameter with the
scan tool while momentarily jumping across the
neutral switch harness connectors between pin 1
of E-11 connector and pin 1 of E-12 connector.
Does the scan tool indicate ON when the circuit is
jumped and OFF when the circuit is not jumped?
6 1. Connect a test lamp between the ignition voltage
feed circuit of the neutral switch harness (pin 1 of
E-12 connector) and a known good ground.
2. Turn ON the ignition, with the engine OFF.
Does the test lamp illuminate?
7 Repair the open circuit or high resistance on the
ignition voltage feed circuit between the ECM (10A)
fuse (EB-4) and the neutral switch (pin 1 of E-12
connector).
Did you complete the repair?
8 1. Test the neutral switch signal circuit between the
engine control module (ECM) (pin 6 of C-57
connector) and the neutral switch (pin 1 of E-11
connector) for an open circuit or high resistance.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
9 1. Turn OFF the ignition.
2. Inspect for
connections at the harness connectors of the
neutral switch (pin 1 of E-11 connector and pin 1
of E-12 connector).
3. Repair the connection(s) as necessary.
Did you find and correct the condition?
10 1. Turn OFF the ignition.
2. Disconnect the ECM harness connector.
3. Inspect for an intermittent and for a poor
connection on the neutral switch circuit at the
harness connector of the ECM (pin 6 of C-57
connector).
4. Repair the connection(s) as necessary.
Did you find and correct the condition?
11 Replace the neutral switch. Refer to Neutral Switch
Replacement in Transmission Section.
Did you complete the replacement?
12 Important: Replacement
programmed.
Replace the ECM. Refer to Engine Control Module
(ECM) Replacement in this section.
Did you complete the replacement?
Action
an intermittent and for
ECM must
Value(s)
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poor
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be
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Engine Control System (4JH1) 6E-201
Yes
Go to Step 9
Go to Step 8
Go to Step 13
Go to Step 13
Go to Step 13
Go to Step 13
Go to Step 13
Go to Step 13
No
Go to Step 6
Go to Step 7
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Go to Step 10
Go to Step 11
Go to Step 12
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