Isuzu 4ja1, Workshop Manual

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6E-144 Engine Control System (4JH1)
DTC P0500 (Symptom Code 1, A) (Flash Code 24)
Circuit Description
The vehicle speed sensor (VSS) is used by the engine
control module (ECM) and speedometer, which
generates a speed signal from the transmission output
shaft. The VSS has the following circuits.
•
Ignition voltage feed circuit
•
VSS signal circuit
•
VSS low reference circuit
The VSS uses a hall effect element. It interacts with the
magnetic field created by the rotating magnet and
outputs square wave pulse signal. The 12 volts
operating supply from the Meter fuse (except 2WD with
A/T) or Back Up fuse (2WD with A/T). The ECM
calculates the vehicle speed by the VSS. If the vehicle
is 2WD with automatic transmission, VSS signals are
sent from the transmission control module (TCM). If the
ECM detects VSS signals are generated with high
frequencies, this DTC will set.
Condition for Running the DTC
•
The ignition switch is ON.
Condition for Setting the DTC
•
The ECM detects that the vehicle speed is higher
than 200 km/h (125 MPH) for 5 seconds.
(Symptom Code 1)
•
The ECM detects that the vehicle speed sensor
signal frequency is too high for 0.6 seconds.
(Symptom Code A)
Action Taken When the DTC Sets
•
The ECM illuminates the malfunction indicator
lamp (MIL) when the diagnostic runs and fails.
•
The ECM uses a vehicle speed substitution of 5
km/h (3 MPH) for engine control.
Condition for Clearing the MIL/DTC
•
The ECM turns OFF the MIL when the diagnostic
runs and does not fail.
•
A history DTC clears after 40 consecutive driving
cycles without a fault. Or clear with the scan tool.
Diagnostic Aids
•
Electrical or magnetic interference may affect
intermittent condition.
•
If an intermittent condition is suspected, refer to
Intermittent Conditions in this section.
DTC P0500 (Symptom Code 1, A) (Flash Code 24)
Schematic Reference:
Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or Engine Control Module (ECM)
Connector End Views
Chart for 2WD with A/T
Step Action Value(s) Yes No
1 Did you perform the Diagnostic System Check-
Engine Controls?

Go to Step 2
Go to Diagnostic
System Check-
Engine Controls
2 1. Inspect all of the circuits going to the automatic
transmission (A/T) 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?

Go to Step 7 Go to Step 3
3 1. Turn OFF the ignition.
2. Disconnect the A/T VSS harness connector.
3. Inspect for an intermittent and for poor
connections at the harness connector of the A/T
VSS (pins 1, 2 and 3 of E-30 connector).
4. Repair the connection(s) as necessary.
Did you find and correct the condition?

Go to Step 7 Go to Step 4