"Dr. Gizmo"
By Phil Arendt
Friendly Disagreement, Settled Then Stirred
Question 1I need your help to settle a bet. My friend and I were discussing tires. He said that some tires can’t be rotated. I disagreed. All tires need rotation. What’s your opinion? D.S., email
Answer 1
Sorry, but your friend is
correct. There are some cars such as the
Chevrolet Corvette in which the tires can’t be rotated due to differences in
size from front to rear. The rear tires
are larger than the front.
Additionally, many vehicles are equipped with directional tires that
can’t be rotated from side to side unless they are removed from the wheels and
remounted on the wheels of the opposite side during a rotation. In such cases most owners just have the front
tires moved to the rear and the rear tires to the front and not crisscrossed. The best rule of thumb for tire rotation is
to follow the carmakers tire rotation recommendation outlined in your owner’s
guide.
Now here’s something that
might stump your buddy. Due to more
stringent tire standards for replacement the Lincoln penny is no longer a tool
to measure tread depth. For decades if
you placed a penny upside down with President Lincoln facing you, if his hairline
showed when inserted in the tread a tire needed replacement. This meant that there was 2/32 inch or less
tread remaining. Now with new tire
standards for safety and fuel economy the George Washington quarter has taken
the place of the penny. The measurement
for replacing a tire is now 4/32 inch of tread remaining. The method of measuring a tire with a quarter
is the same as with a penny but now if President Washington’s hairline shows
the tire needs replacement.
Shop Lacks Test Equipment
Question 2
My 2008 Mitsubishi cranks
when I turn the key but it won’t start.
I cranked it until the battery died and called AAA. The tow truck driver jumped the battery but
it still would not start. I had him tow
the car to my repair shop.
The car will not start for my
shop. They have done all kinds of tests
but cannot determine the trouble. My
mechanic thinks there is a problem in the antitheft system. He asked if I have another key because that
might start the car. Unfortunately, I
purchased the car a little over a year ago and the dealer did not give me two
keys.
My mechanic says his tester
does not have the capability to communicate with the system and suggested that
I have the car towed to a dealership. Is
this my only alternative? T.R., email
Answer 2
You could have the car
crushed at a salvage yard. All kidding
aside, if you are dead set against taking the car to a dealership another independent
shop might have the equipment to communicate with the antitheft system and body
control module. To find a repair shop with
the proper equipment consider calling a AAA-Approved Auto Repair shop. Call your local AAA for a list of shops. One might have the tool to do the work. If not, the next stop for your car is a
dealership and it is possible a Mitsubishi dealership is AAA-Approved. Also, once the car is repaired consider
investing in a second key just in case the present key fails to communicate
with the antitheft system.
In A Quandary Over Where To
Take Car For Repair
Question 3
A “Service Park Assist”
light has turned on in my 2007 Cadillac DTS and the system does not
function. My car has 91,000 miles on it.
Is this something that can be
repaired at an independent repair shop or do I have to go to a dealer shop? T.D.S., email
Answer 3
It all depends upon the
repair shop. Some independent repair
shops have the expertise and tools to communicate and program control modules
and some don’t. It’s likely a shop with
a great reputation that has been in business for many years will have the tools
and a technician that can do the work. A
shop with a great reputation that lacks a particular tool and or expertise to
perform an operation will refer you to a dealership or another shop that can
handle the task.
Definitely a dealership will
have the tools and technician to diagnose and repair the system.
Runaway Truck
Question 4Since replacing the battery in my 2003 Chevrolet Silverado 3500 the gas pedal has been sticking. When accelerating and I reach cruising speed I can release the gas pedal and the truck continues to accelerate for as long as ten seconds. The first time this happened I thought I had the cruise control on but it wasn’t. I pulled to the side of the road to make sure nothing was interfering with the gas pedal but the floor mat was not touching nor did the pedal bind when pressing and releasing it. Since this event the engine has accelerated on its own a few more times so I’m careful to maintain a large interval between my truck and vehicles ahead of me.
I went to a repair shop
where a technician examined the gas pedal and did a number of tests. He drove the truck with a scan tester
connected to a computer. He experienced
the acceleration trouble but could not find any problems. He suggested that I leave it for a few days
so he can track down the cause of the trouble.
As of yet, I have not left it at the shop.
Have you ever heard of
trouble like this? D.L., email
Answer 4
The gas pedal in your truck
operates an electric switch that signals the opening and closing of the throttle
on the engine. Certainly it is possible
the switch has a fault but tests should reveal issues that would tell a
technician there is trouble.
Since so far tests have not
found abnormalities it is time to consider tests of the cruise control. He might consider examination of switches and
module associated with the cruise control.
Examination of the conductors in the cruise control circuit including
ground connections and terminals in plugs is in order.
Before your technician
begins tests he might consider disconnecting the cruise control. Once this is accomplished a test drive may
find the condition does not occur with the cruise disabled. If so, he can focus on faults in that system
and abandon troubleshooting the gas pedal circuit although they are
interconnected.
Poor Connection Causes
Trouble
Question 5
I have a 1991 Volkswagen
Vanagon camper with 107,000 miles. The
vehicle is in great condition and has not given me a bit of trouble until
now. I use the vehicle for camping and
during the winter months it is parked in my garage. Occasionally, during the winter I drive it on
nice days to keep it in good working order.
The last time I drove the engine hesitated and bucked as if it was going
to stall. I took it to a repair shop that
has maintained it for several years. A
technician has done all kinds of tests and has replaced several parts including
the engine control module but the trouble remains. Now he is at a loss.
I’m not about to give up on
this vehicle. I have always changed the
oil every 3,000 miles or 3 months and follow the factory service schedule for
everything else. Do you have any
suggestions? P.W., email
Answer 5
It’s a good thing this
problem did not occur during a camping trip.
It certainly is not time to dump the camper.
At this stage of repair ask
your technician to consider a thorough check of all the electrical ground
connections. As a vehicle ages, ground
connections are prone to suffer from corrosion or become loose. When this occurs unusual driveability
conditions develop that can stump even the most experienced technician.
Once he examines the ground
connections it is likely he will find the cause of the trouble. Renewing a good electrical path at a ground
circuit will likely place your trusty VW back into service as your mode of
transportation to your next camping destination.
New Fuse Might Fix Trouble
Question 6
Yesterday, I went to start
my 2000 Dodge Durango with a 4.7-liter engine.
It cranked and cranked but would not start. Thankfully I have a second car so I could get
to work. After work I tried to start it
and it just cranked. Then I realized the
odometer had a message that said “P done”.
Also, the interior lights and power door locks do not work.
My Durango has 160,000 miles
on it. It usually runs fine. I don’t want to put a lot of money into
it. Do you have any idea what the trouble
is? P., email
Answer 6
The message decoded means
let me pass in gracefully. All kidding
aside, this might be an easy repair.
Your truck sent a message to
the odometer that means no codes. Since
the interior lights and power locks do not work, this could mean that there is
no power to the body control. The body
control module sends a code to the engine module to start. Check the fuses. You might find the fuse for the power door
locks is open or blown. If so,
replacement could get your truck back on the road. If a new fuse blows there is a short
somewhere in the circuit that needs troubleshooting. If it doesn’t blow, you’ll likely jump for
joy when your truck springs back to life.
Keep your fingers crossed
that a new fuse does the trick.
Thanks for all of your great
questions. Dr. Gizmo can’t wait to
answer more.
Phil Arendt is a
columnist, consultant and A.S.E.-Certified Master Technician. Readers may send questions to Dr. Gizmo at
P.O. Box 548, Cary, IL. 60013 or e-mail address drgizmo@hotmail.com 01/14/2013 ® DR. GIZMO © 1989-Present
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