Isuzu 4JA1 Workshop Manual page 401

DTC P0500 (Symptom Code B) (Flash Code 24)
Circuit Description
The vehicle speed sensor (VSS) is used by the engine
control module (ECM)
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 not generated, this DTC
will set.
Condition for Running the DTC
• The ignition switch is ON.
• The engine speed is higher than 3600 RPM.
• The fuel injection quantity is more than 41 mg/strk.
Chart for 2WD with A/T
Step
1 Did you perform the Diagnostic System Check-
Engine Controls?
2 1. Install the scan tool.
2. Turn OFF the ignition for 30 seconds.
3. Turn ON the ignition, with the engine OFF.
4. Select the "JR405E Automatic Transmission" in
the system selection menu.
5. Monitor the Read Diagnostic Trouble Code
(DTC) Info As Stored By ECU with the scan tool.
Does the transmission control module (TCM) DTC
P0722 set?
3 1. Drive the vehicle.
2. Select the data display function of engine control
module (ECM).
3. Observe the Vehicle Speed parameter with the
scan tool.
Does the Vehicle Speed parameter indicate correct
vehicle speed?
4 1. Turn OFF the ignition.
2. Disconnect the TCM harness connector.
3. Turn ON the ignition, with the engine OFF.
4. Intermittently jump the VSS signal output circuit
(pin 10 of C-94 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?
and speedometer, which
Action
Engine Control System (4JH1) 6E-147
Condition for Setting the DTC
• The ECM detects that the vehicle speed is lower
than 1.5 km/h (1 MPH) for 60 seconds.
Action Taken When the DTC Sets
• The ECM illuminates the malfunction indicator
lamp (MIL) when the diagnostic runs and fails.
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 B) (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
Value(s) Yes

Go to Step 2

Go to Applicable
DTC in Automatic
Transmission
Section

Go to Diagnostic
Aids

Go to Step 8
No
Go to Diagnostic
System Check-
Engine Controls
Go to Step 3
Go to Step 4
Go to Step 5