Isuzu 4JA1 Workshop Manual page 404

6E-150 Engine Control System (4JH1)
Step
5 1. Remove the vehicle speed sensor (VSS). Refer
to Vehicle Speed Sensor (VSS) Replacement in
this section.
2. Visually inspect the VSS for the following
conditions:
•
Physical damage
•
Being loose
•
Improper installation
•
For transmission output shaft teeth damage
3. Repair or replace as necessary.
Did you find and correct the condition?
6 1. Turn OFF the ignition.
2. Disconnect the VSS harness connector.
3. Connect a test lamp between the ignition voltage
feed circuit of the VSS harness (pin 1 of E-44
connector) and a known good ground.
4. Turn ON the ignition, with the engine OFF.
Does the test lamp illuminate?
7 1. Turn ON the ignition, with the engine OFF.
2. Connect a test lamp between the ignition voltage
feed circuit and low reference circuit of the VSS
harness (pins 1 and 2 of E-44 connector).
Does the test lamp illuminate?
8 1. Turn ON the ignition, with the engine OFF.
2. Intermittently jump the signal circuit of the VSS
(pin 3 of E-44 connector) with a test lamp that is
connected to a known good ground while
monitoring the Vehicle Speed parameter with the
scan tool.
Does the scan tool indicate any vehicle speed when
the circuit is intermittently pulled to ground?
9 Repair the open or high resistance in the VSS
ignition voltage feed circuit between the Meter (10A)
fuse (C-14) and the VSS (pin 1 of E-44 connector).
Did you complete the repair?
10 Repair the open or high resistance in the VSS low
reference circuit between the VSS (pin 2 of E-44
connector) and the chassis ground.
Did you complete the repair?
11 1. Turn OFF the ignition.
2. Remove the instrument panel (IP) cluster in order
to disconnect the B-23 harness connector.
3. Disconnect
connector.
4. Turn ON the ignition, with the engine OFF.
5. Intermittently jump the signal output circuit of the
VSS signal (pin 8 of B-23 connector) with a test
lamp that is connected to a known good ground
while monitoring the Vehicle Speed parameter
with the scan tool.
Does the scan tool indicate any vehicle speed when
the circuit is intermittently pulled to ground?
Action
the IP cluster B-23
Value(s)






harness

Yes
Go to Step 20 Go to Step 6
Go to Step 7 Go to Step 9
Go to Step 8 Go to Step 10
Go to Step 14 Go to Step 11
Go to Step 20
Go to Step 20
Go to Step 12 Go to Step 13
No

