Toyota Camry Manual page 1295

DI–268
HINT:
D
When the DTC P0171 is recorded, the actual air–fuel ratio is on the lean side. When DTC P0172 is
recorded, the actual air–fuel ratio is on the rich side.
D
If the vehicle runs out of fuel, the air–fuel ratio is lean and DTC P0171 is recorded. The MIL then comes
on.
D
If the total of the short–term fuel trim value and long–term fuel trim value is within 35 % (80°C (176°F)
or more), the system is functioning normally.
D
The A/F sensors (bank 1, 2 sensor 1) output voltage and the short–term fuel trim value can be read
using the OBD II scan tool or TOYOTA hand–held tester.
D
The ECM controls the voltage of AFRX, AFLX, AFRu and AFLu terminals of ECM to the fixed volt-
age. Therefore, it is impossible to confirm the A/F sensor output voltage without OBD II scan tool or
TOYOTA hand–held tester.
D
OBD II scan tool (excluding TOYOTA hand–held tester) displays the one fifth of the A/F sensors (bank
1, 2 sensor 1) output voltage which is displayed on the TOYOTA hand–held tester.
INSPECTION PROCEDURE
Read freeze frame data using TOYOTA hand–held tester or OBD II scan tool. Because freeze frame records
the engine conditions when the malfunction is detected, when troubleshooting it is useful for determining
whether the vehicle was running or stopped, the engine warmed up or not, the air–fuel ratio lean or rich, etc.
at the time of the malfunction.
1 Check air induction system (See page SF–1).
OK
2 Check injector injection (See page SF–25).
OK
3 Check mass air flow meter and engine coolant temp. sensor
(See pages SF–35 and SF–63).
OK
DIAGNOSTICS – ENGINE (1MZ–FE)
NG Repair or replace.
NG Replace injector.
NG Repair or replace.
Author : Date :
503