MAINTENANCE
493
EMISSION INSPECTION AND
MAINTENANCE (I/M) PROGRAMS
Some states have vehicle emission inspection programs
which include OBD (On-Board Diagnostics) checks.
The OBD system monitors the operation of the emission
control system. When the OBD system determines that a
problem exists somewhere in the emission control system, the
malfunction indicator lamp comes on. In this case, your vehicle
may not pass the I/M test and need to be repaired. Contact
your Lexus dealer to service the vehicle.
Even if the malfunction indicator lamp does not come on, your
vehicle may not pass the I/M test as readiness codes have not
been set in the OBD system.
Readiness codes are automatically set during ordinary driving.
However, when the battery is disconnected or run down, the
codes are erased. Also, depending on your driving habits, the
codes may not be completely set.
Also, if the malfunction indicator lamp had come on recently
due to temporary malfunction such as a loose fuel tank cap,
your vehicle may not pass the I/M test.
The malfunction indicator lamp will go off after taking several
driving trips, but the error code in the OBD system will not be
cleared unless about 40 trips or more are taken.
If your vehicle does not pass the I/M test and the malfunction
indicator lamp does not come on, contact your Lexus dealer to
prepare the vehicle for re-testing.
ENGINE
511 Lexus recommends the use of gasoline that contains
detergent additives to avoid build-up of engine deposits.
However, all gasoline sold in the U.S. contains detergent
additives to keep clean and/or clean intake systems.
Quality gasoline
Automotive manufacturers in the U.S., Europe and Japan
have developed a specification for quality fuel named
World-W ide Fuel Charter (WWFC) that is expected to be
applied world wide. The WWFC consists of four
categories that depend on required emission levels. In the
U.S., category 3 has been adopted. The WWFC improves
air quality by providing for better emissions in vehicle
fleets, and customer satisfaction through better vehicle
performance.
Cleaner burning gasoline
Cleaner burning gasoline, including reformulated
gasoline that contains oxygenates such as ethanol or
MTBE is available in many areas.
Lexus recommends the use of cleaner burning gasoline and
appropriately blended reformulated gasoline. These types of
gasoline provide excellent vehicle performance, reduce
vehicle emissions, and improve air quality.
Oxygenates in gasoline
Lexus allows the use of oxygenate blended gasoline
where the oxygenate content is up to 10% ethanol or 15%
MTBE. If you use gasohol in your Lexus, be sure that it has
an octane rating no lower than 87.
Lexus does not recommend the use of gasoline containing
methanol.
Gasoline containing MMT
Some gasoline contain an octane enhancing additive
called MMT (Methylcyclopentadienyl Manganese
Tricarbonyl).
Lexus does not recommend the use of gasoline that contains
MMT. If fuel containing MMT is used, your emission control
system may be adversely affected. The Malfunction Indicator
Lamp on the instrument cluster may come on. If this happens,
contact your Lexus dealer for service.
