Vehicle-down Sensor (Service Code 31)
Vehicle-down Sensor Input Voltage Inspection
Be sure the battery is fully charged.
Remove the vehicle-down sensor (see Vehicle-down
Connect the measuring adapter [A] between the main har-
ness connector and vehicle-down sensor connector as
Main Harness [B]
Vehicle-down Sensor [C]
Special Tool - Measuring Adapter: 57001-1700
Connect a digital meter [D] to the measuring adapter
Vehicle-down Sensor Input Voltage
Connections to Adapter:
Digital Meter (+) → R (main harness BL) lead
Digital Meter (–) → BK (main harness BR/Y) lead
Measure the input voltage with the engine stopped and
with the connector joined.
Turn the ignition switch ON.
Standard: DC 4.75 ∼ 5.25 V
Turn the ignition switch OFF.
If the reading is within the standard, check the output volt-
age (see Vehicle-down Sensor Output Voltage Inspec-
If the reading is out of the standard, remove the ECU
and check the wiring for continuity between main harness
Special Tool - Hand Tester: 57001-1394
Disconnect the ECU and sensor connectors.
Wiring Continuity Inspection
ECU Connector [A] ←→
Vehicle-down Sensor Connector [B]
BL lead (ECU terminal 48) [C]
BR/Y lead (ECU terminal 55) [D]
If the wiring is good, check the ECU for its ground and
power supply (see ECU Power Supply Inspection).
If the ground and power supply are good, replace the ECU
(see ECU Removal/Installation).
FUEL SYSTEM (DFI) 3-65