Isuzu N 2008 Series Workshop Manual page 185

1A-182 Engine Control System (4JJ1)
Step
1. Inspect the VSS, drive gear, driven gear or
output shaft for the following conditions:
• Physical damage of sensor, drive gear or
driven gear
• Loose or improper installation of sensor,
drive gear or driven gear
4
• Transmission output shaft teeth damage
• Excessive transmission output shaft play
2. Disconnect the aftermarket signal pulse pick
up device and retest if installed.
3. Repair or replace as necessary.
Did you find and correct the condition?
1. Turn OFF the ignition.
2. Inspect
connections and corrosion at the harness
connector of the VSS (pins 1, 2 and 3 of J48).
3. Disconnect the ECM harness connector.
5
4. Inspect for an intermittent, for a poor
connection and corrosion at the harness
connector of the ECM (pin 19 of J14).
5. 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.
6
Did you complete the replacement?
1. Reconnect
harness connector(s).
2. Clear the DTCs with a scan tool.
3. Turn OFF the ignition for 30 seconds.
7
4. Drive the vehicle while observing the Vehicle
Speed parameter with a scan tool.
Does the scan tool indicate correct vehicle speed?
Observe the DTC Information with a scan tool.
8
Are there any DTCs that you have not diagnosed?
Circuit/ System Testing DTC P0500 (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. Turn ON the ignition, with the engine OFF.
2
4. Monitor the DTC Information with a scan tool.
Is DTC P0502 or P0503 also set?
Drive the vehicle while observing the Vehicle
Speed parameter with a scan tool.
3
Does the scan tool indicate correct vehicle speed?
Action
for an intermittent,
all previously disconnected
Action
Value(s)
—
for poor
—
—
—
—
Value(s)
—
—
—
Yes
Go to Step 7
Go to Step 7
Go to Step 7
Go to Step 8
Go to DTC List
Yes
Go to Diagnostic
System Check -
Go to Step 2 Engine Controls
Go to Applicable
DTC
Go to Diagnostic
Aids
No
Go to Step 5
Go to Step 6
—
Go to Step 2
System OK
No
Go to Step 3
Go to Step 4