NOTE
Be sure the battery is fully charged.

Main Harness [B] Oxygen Sensor [C]
Special Tool - Measuring Adapter: 57001-1700
Oxygen Sensor Heater Power Source Voltage Connections to Adapter: Digital Meter (+) → R (main harness W/R) lead Digital Meter (–) → Frame Ground terminal

Power Source Voltage Standard: Battery Voltage
If the reading is in specification, but the problem still exists, replace the ECU (see ECU Removal/Installation in the Fuel System (DFI) chapter).
If the reading is out of the standard, check the following.
ECU Relay Fuse 15 A (see Fuse Inspection in the Electrical System chapter) Power Source Wiring (see Oxygen Sensor Circuit)
If the fuse and wiring are good, remove the ECU and check the wiring for continuity between harness connectors.
Special Tool - Hand Tester: 57001-1394
Disconnect the ECU and sensor connectors.

Wiring Continuity Inspection ECU Connector [A] ←→ Oxygen Sensor Connectors [B] R lead (ECU terminal 76) [C]
If the wiring is good, check the ECU for its ground and power supply (see ECU Power Supply Inspection in the Fuel System (DFI) chapter).
If the ground and power supply are good, replace the ECU (see ECU Removal/Installation in the Fuel System (DFI) chapter).
Oxygen Sensor Circuit

1. ECU
2. Oxygen Sensor
3. Ignition Switch
4. Joint Connector F
5. Joint Connector A
6. Fuse Box 1
7. Ignition Fuse 15 A
8. Relay Box
9. ECU Main Relay
10. Frame Ground 3
11. Starter Relay
12. ECU Fuse 15 A
13. Main Fuse 30 A
14. Battery
15. Engine Ground
Oxygen Sensor Heater Resistance Inspection
KIBS Hydraulic Unit Communication Error (Service Code 1b, KIBS Equipped
Models)Self-Diagnosis Procedures
NOTE
Use a fully charged battery when conducting
self-diagnosis. Otherwise, the light (LED) and symbol
do not light or blink.
Turn the ignition switch to ON.
When a problem occurs with DFI system and ignition system,
the warning indicator light (LED) [A] goes on and
FI warning symbol ...
Fuel Pump Installation
Remove dirt or dust from the fuel pump [A] by lightly applying
compressed air.
Replace the fuel pump gasket with a new one.
Check that the fuel pump terminal [A] and band [B] are in
place.
Apply a non-permanent locking agent to the threads of
the fuel pump bolts.
Tighten the ...
Intake Air Pressure Sensor #1 Output Voltage Inspection
Measure the output voltage at the intake air pressure sensor
#1 in the same way as input voltage inspection, note
the following.
Disconnect the intake air pressure sensor #1 connector
and connect the measuring adapter [A] between these
connectors.
[B] Main Harness
[C] Intake Air Pressu ...