Isuzu 4JA1 Workshop Manual page 399

Step
4 1. Turn OFF the ignition.
2. Disconnect the engine control module (ECM)
harness connector.
3. Inspect for an intermittent and for a poor
connection on A/T VSS circuit at the harness
connector of the ECM (pin 68 of C-56 connector).
4. Repair the connection(s) as necessary.
Did you find and correct the condition?
5 1. Remove the A/T VSS. Refer to A/T Speed
Sensor Replacement in automatic transmission
section.
2. Visually inspect the A/T VSS for the following
conditions:
•
Physical damage
•
Being loose
•
Improper installation
3. The following conditions may cause this DTC to
set:
•
Electromagnetic interference in the A/T
VSS circuits
4. Repair or replace as necessary.
Did you find and correct the condition?
6 Replace the A/T VSS. Refer to A/T Speed Sensor
Replacement in automatic transmission section.
Did you complete the replacement?
7 1. Reconnect all previously disconnected harness
connector(s).
2. Clear the DTCs with the scan tool.
3. Turn OFF the ignition for 30 seconds.
4. Drive the vehicle.
5. Observe the Vehicle Speed parameter with the
scan tool.
Does the Vehicle Speed parameter indicate correct
vehicle speed?
8 Observe the DTC Information with the scan tool.
Are there any DTCs that you have not diagnosed?
Chart for except 2WD with A/T
Step
1 Did you perform the Diagnostic System Check-
Engine Controls?
2 1. Inspect all of the circuits going to the vehicle
speed sensor (VSS) for the following:
•
Routed too closely to fuel injection solenoid
wiring or components
•
Routed too closely to after-market add-on
electrical equipment
•
Routed too closely to solenoids, relays, and
motors
2. If you find incorrect routing, correct the harness
routing.
Did you find and correct the condition?
Action
Action
Engine Control System (4JH1) 6E-145
Value(s) Yes

Go to Step 7

Go to Step 7

Go to Step 7

Go to Step 8
Go to Diagnostic

Trouble Code (DTC)
List
Value(s) Yes

Go to Step 2

Go to Step 7
No
Go to Step 5
Go to Step 6

Go to Step 2
System OK
No
Go to Diagnostic
System Check-
Engine Controls
Go to Step 3