Isuzu 2008MY N Series Workshop Manual page 205

1A-202 Engine Control System (4HK1)
Step
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
observed from the Freeze Frame/ Failure
Records.
Did the DTC fail this ignition?
Observe the DTC Information with a scan tool.
14
Are there any DTCs that you have not
diagnosed?
Circuit/ System Testing DTC P0502 (Model with ABS)
Step
Did you perform the Diagnostic System Check
1
- Engine Controls?
1. Install a scan tool.
2. Turn OFF the ignition for 30 seconds.
3. Start the engine.
2
4. Monitor the DTC Information with a scan tool.
Does the DTC fail this ignition?
Observe the ABS DTCs information with a scan
tool.
3
Is DTC C0251, C0252, C0253, C0254,
C0261, C0262, C0263 or C0264 set?
1. Turn OFF the ignition.
2. Disconnect the EHCU harness connector.
3. Turn ON the ignition, with the engine OFF.
4 4. Connect a test lamp between the vehicle
speed signal circuit (pin 14 of J-22) and a
battery voltage.
Does the test lamp illuminate?
1. Leave the test lamp connected between the
EHCU 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 also set?
1. Test the vehicle speed signal circuit between
the ECM (pin 19 of J-14) and the EHCU (pin
14 of J-22) for a short to ground or short to the
low reference.
6
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
Action
within the conditions
Action
Value(s)
—
that you
—
Value(s)
—
—
—
—
—
—
Yes
Go to Step 3 Go to Step 14
Go to DTC List
Yes
Go to Diagnostic
System Check -
Go to Step 2 Engine Controls
Go to Diagnostic
Go to Step 3
Go to Applicable
DTC
Go to Step 6
Go to Step 8
Go to Step 12
No
System OK
No
Aids
Go to Step 4
Go to Step 5
Go to Step 7
Go to Step 11