Isuzu N 2008 Series Workshop Manual page 188

Step
1. Leave the test lamp connected between the
VSS harness connector and battery voltage.
2. Turn OFF the ignition for 30 seconds.
5
3. Turn ON the ignition, with the engine OFF.
4. Monitor the DTC Information with a scan tool.
Is DTC P0503 set?
Repair the open circuit or high resistance on the
ignition voltage feed circuit between the ABS (10A)
fuse and the VSS (pin 1 of J48). Check the ABS
6
(10A) fuse first.
Did you complete the repair?
1. Test the signal circuit between the ECM (pin
19 of J14) and the VSS (pin 3 of J48) for a
short to ground or short to the low reference.
7
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
1. Test the signal circuit between the ECM (pin
19 of J14) and the VSS (pin 3 of J48) for an
open circuit or high resistance.
8
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
VSS (pins 1 and 3 of J48).
9
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
10
ECM (pin 19 of J14).
4. Repair the connection(s) as necessary.
Did you find and correct the condition?
Replace the VSS. Refer to Vehicle Speed Sensor in
Section 9E Instrumentation/ Driver Info.
11
Did you complete the replacement?
Important: Replacement
programmed and learned.
12
Replace the ECM. Refer to ECM Replacement.
Did you complete the replacement?
1. Reconnect all previously disconnected fuse or
harness connector(s).
2. Clear the DTCs with a scan tool.
3. Turn OFF the ignition for 30 seconds.
4. Start the engine.
13
5. Operate the vehicle within the Conditions for
Running the DTC. You may also operate the
vehicle within
observed from the Freeze Frame/ Failure
Records.
Did the DTC fail this ignition?
Action
ECM must
the conditions that
Engine Control System (4JJ1)
Value(s)
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be
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you
Yes
Go to Step 9 Go to Step 8
Go to Step 13
Go to Step 13 Go to Step 12
Go to Step 13 Go to Step 10
Go to Step 13 Go to Step 11
Go to Step 13 Go to Step 12
Go to Step 13
Go to Step 13
Go to Step 3 Go to Step 14
1A-185
No
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