Repair The Circuit(S) As Necessary - Isuzu 2008MY N Series Workshop Manual

Step
Drive the vehicle. (Lift the driving wheels as
necessary)
7
Does the engine warm up control cancel?
Observe the Engine Warm Up Switch parameter
with a scan tool.
8
Does the scan tool indicate ON?
Observe the Exhaust Brake Valve Command
parameter with a scan tool.
Does the scan tool indicate ON?
9
1. Turn OFF the ignition.
2. Remove the bezel surrounding the instrument
panel (IP) cluster enough to disconnect the
engine warm switch.
3. Disconnect the engine warm up switch
harness connector.
10
4. Connect a test lamp between the voltage feed
circuit of the switch harness (pin 1 of B-168)
and a known good ground.
5. Start the engine.
Does the test lamp illuminate?
Observe the Engine Warm Up Switch parameter
with a scan tool while momentarily jumping 3-amp
fused jumper wire across the switch harness
connector between pins 1 and 2 of B-168.
11
Does the scan tool indicate ON when the
circuit is jumpered and OFF when the circuit is
not jumpered?
Repair the open circuit or high resistance between
the ECM (10A) fuse and the switch (pin 3 of B-168).
12
Did you complete the repair?
1. Test the signal circuit between the ECM (pin
51 of J-14) and the switch (pin 2 of B-168) for
an open circuit or high resistance.
13
2.

Repair the circuit(s) as necessary.

Did you find and correct the condition?
1. Inspect for an intermittent and for poor
connections at the harness connector of the
switch (pins 1 and 2 of B-168).
14
2. Repair the connection(s) as necessary.
Did you find and correct the condition?
1. Turn OFF the ignition.
2. Disconnect the ECM harness connector.
3. Inspect for an intermittent and for a poor
connection at the harness connector of the
15
ECM (pin 51 of J-14).
4. Repair the connection(s) as necessary.
Did you find and correct the condition?
Action
Engine Control System (4HK1)
Value(s) Yes
—
System OK
—
Go to Step 9
Problem is relating
either solenoid
valves, exhaust
brake valve or
—
vacuum pressure
lines. Go to Exhaust
Brake Control
System Check
—
Go to Step 11
—
Go to Step 14
—
Go to Step 20
—
Go to Step 20
—
Go to Step 20
—
Go to Step 20
1A-327
No
Observe the Vehicle
Speed parameter.
Refer to DTC P0500
Go to Step 10
The ECM is not
allowing engine
warm up control.
Refer to Engine
Warm Up Control
Operation
Go to Step 12
Go to Step 13
—
Go to Step 15
Go to Step 18
Go to Step 19