preludejtstyle

Welcome to OBD II
The ’95 Accord V6 was the first Honda to feature a
PGM-FI system that meets the new on-board diagnostics
(OBD) requirements known as OBD II. The rest of our
models will have OBD II systems by the ’96 model year.
OBD II is a comprehensive diagnostic system designed
to allow any skilled technician to repair an engine
management system problem on any OBD-II-equipped
vehicle with the aid of an OBD-II-compatible scan tool.
With the scan tool, you can now read much of the same
sensor data that the engine control module (ECM) sees.
In many cases, you no longer have to reproduce a
diagnostic trouble code (DTC); reading the data will tell
you whether there’s a malfunction or not.
The SAE-established OBD II guidelines include these
changes:
• A universal 16P diagnostic connector, with
standardized pin assignments, called the data link
connector (DLC).
• A standard list of DTCs for all manufacturers.
• Data snapshot capability in the ECM when a fault
occurs.
• The ability to record a DTC whenever a fault occurs
that affects emissions.
• The ability to erase DTCs with the scan tool.
The SAE-defined DTCs, for example P0131, are
five-character alphanumeric codes:
• First character, area of vehicle: B for body, C for
chassis, P for powertrain, and U for undefined.
(Currently, only powertrain codes have been defined.)
• Second character, code origin: 0 for SAE-controlled
codes, 1 for manufacturer-controlled codes.
• Third character, system affected: 1 and 2 for fuel and
air metering, 3 for ignition system or misfire, 4 for
auxiliary emission controls, 5 for vehicle speed and
idle controls, 6 for computer and output circuits, and 7
and 8 for transmission.
• Fourth and fifth characters, the fault: general
malfunction, high or low voltage or frequency, or “out
of range.�

Clearing ABS Wheel
Sensor DTCs
When some vehicles with ABS are run on a lift, the
ABS control unit can set a wheel sensor DTC(s) and
turn on the ABS indicator. Some wheel sensor DTCs
keep the ABS indicator on until the vehicle is driven
above 7 mph.
To turn off the ABS indicator, clear the DTC with a
PGM Tester, and drive the vehicle above 7 mph.
When the ABS control unit gets a normal vehicle
speed input from all four wheels, it completes the
ABS DTC clearing procedure and turns off the
indicator.

Coping With Static Shock
Static shock can be irritating to downright painful.
That’s because when you get shocked from what’s
commonly called “static electricity� it’s really high
voltage electricity. Depending on conditions, it can
actually reach a potential of several thousand volts,
and the drier the air, the greater your chances of
getting shocked.
What Causes Static Shock
Static electricity appears whenever the quantities of
positive and negative electrical charges in something
aren’t perfectly equal. Normally the positives cancel
the negatives, and everything behaves electrically
neutral. But if two insulators of different materials
contact each other, then the electrical charges of the
material transfer between the surfaces. One surface
ends up with more negative charges than positive,
and has a negative charge imbalance. The other
surface has fewer negative charges than positive, so it
has a positive charge imbalance. Both surfaces are
electrically charged and a high potential voltage exists
between them.
As long as these surfaces stay together, their electrical
charges cancel each other out. But if you separate
them, you also separate their polarities (a positive
charge stays with one, a negative charge with the
other). Now the potential voltage between the two
surfaces rises dramatically. If you bring the two
surfaces back together, at some point, the opposite
polarities jump the gap and rejoin, producing a
high-voltage spark.
From our little science lesson, you can see what
happens in dry weather when you step out of the
vehicle and get shocked closing the door. Your body
becomes electrically charged from your clothes (an
insulator) contacting the seats and seat-backs (a
different insulator). When you step out, you’re taking
just one polarity of charge along with you, while the
seat keeps the opposite polarity. At the same time, the
seat is causing the entire vehicle to become
electrically charged by a process called “Faraday’s
Icepail Effect.� The potential voltage between you
and the vehicle now surges up to 10,000 or even
20,000 volts. If you’re wearing shoes, especially those
with rubber soles, the charge has no chance to leak to
ground. So when you reach out to close the door,
which is grounded to the vehicle, the opposite
polarities rejoin at your finger and ZAP!, you get
shocked.
How to Prevent Static Shock
Now that you know what causes static shock, what
can be done to prevent it? Here are some helpful tips
to pass along to your customers:
• Avoid wearing clothes that contribute to static
shock. Clothes made from wool or from synthetic
materials such as nylon, polyester, or plastic, put a
greater electrical charge on your body than clothes
made from cotton or other materials. (A ’98 study
done in the UK recorded peak body voltages of
21,000 volts when wearing nylon clothes, 9,000
volts for wool clothes, and 7,000 volts for cotton
clothes.) Also, consider choosing leather upholstery
instead of fabric. Fabric upholstery creates a greater
charge imbalance than leather does.
• Shoe soles create a charge imbalance and work as
insulators as well. To avoid getting shocked, don’t
wear rubber-soled shoes—they create a significant
charge imbalance, and when you step out of the
vehicle, the insulating properties of rubber keep the
charge from leaking to ground. Try wearing thin,
leather-soled shoes instead.
• Try getting into the habit of holding your keys as
you step out of the vehicle, then grip one of the
keys firmly by the metal, and tap the door lock
cylinder with the tip of the key. The spark will still
jump, but it won’t be painful. The tip of the key will
take the spark’s punishment instead of your tender
finger.
• Try spraying the seats, seat-backs, floor mats, and
carpet with some anti-static liquid such as
ScotchGard or Static Gard, or your own brew from
mixing 1 part liquid fabric softener with 10 parts
water. This spray treatment dampens the surfaces
making them slightly conductive, so the separated
charges can instantly flow back together. This
treatment generally lasts up to 3 months. On
vehicles with side airbags, don’t get the front
passenger’s seat too wet, or it may trigger the SIDE
AIRBAG indicator (see the article Side Airbag
Indicator Comes On in the November ’00 edition.)
• If you get shocked when you drive up and touch
outside objects that are grounded (mail boxes, toll
booths, drive-up ATMs, etc.), the vehicle itself has
probably created a charge imbalance. Waiting
several seconds before touching any outside objects
that are grounded can sometimes allow the charge
to dissipate.

__________________