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Question: I have a
2006 Honda Odyssey with 90,000 miles. Under hard braking
above 50 miles per hour, the car shakes. Below 50 mph,
hard braking seems normal with no shaking. Actual
stopping performance doesn't seem affected. Your best
guess would help me in dealing with the dealer or brake
repair shop.
Answer: Front brake
rotors that are warped, worn or vary in thickness can
cause this type of vibration. A binding or sticking
caliper might cause the pads to overheat, creating a
vibration while braking at speed. And at 90,000 miles,
there may be enough normal wear and tear that it's time
for new pads and possibly new rotors.
But don't forget to have
the shop check the steering and suspension components
for any damage or wear. A bent steering arm, worn ball
joint or steering rod end or even a dead shock or strut
could cause this type of vibration.
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Q: I have a 2008 Buick
Lucerne. From day one, the cruise control has not worked
properly. It works one day and the next it doesn't. The
dealership has replaced a module to no avail. It will
work, and I'll stop for lunch for 30 minutes and get
back on the highway and it won't work. There must be a
switch stuck somewhere. The dealership doesn't know what
else to do. Can you help?
A: If by "not
worked" you mean that you cannot engage the cruise
control, the cruise control switch is certainly a
potential culprit. The switch provides a voltage signal
input to the BCM (body control module), which then
communicates this to the ECM (engine control module). My
Alldata automotive database pulled up a relatively
simple test measuring resistance through the various
circuits of the steering wheel-mounted switch.
In addition, a scan tool
can identify any B-series fault codes in the cruise
control circuits.
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Q: I own a 3.4-liter 2003
Pontiac Montana with only 56,000 miles. When I recently
took it to the dealership to have the engine oil
changed, they informed me that my intake manifold gasket
was failing and that I should have it replaced. As far
as I know they did not do any engine testing. The car
does not leak any antifreeze or oil.
After some research, I
found out that Pontiac had problems with the intake
gasket for this vehicle. What tests are needed to
diagnose an intake manifold gasket failure, or can a
tech just tell that the gasket is failing by just
looking at the engine?
A: In most cases, an
intake manifold coolant or oil leak will reveal itself
with drips on the garage floor and/or having to add oil
or coolant periodically. My Alldata pulled up GM
bulletin 03-06-01-010C, dated April 2008, that addresses
this issue based on owner's complaints of oil or coolant
leaks. Have the dealership show you the physical
evidence of leaking: residue, stains or wetness on the
engine or transmission.
Internal leakage might
lead to oil contaminating the coolant or vice versa.
This could be much more damaging to the engine, so make
sure there's no evidence of oil in the coolant or
antifreeze on the oil dipstick.
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Q: Recently, the little
box on my instrument panel of my 2004 Ford F-150 went
blank. It lights up, but there is no display of
odometer, compass or temperature. Any thoughts?
A: A scan tool can check
for fault codes from the display itself, and identify
any communication problems in the controller area
network circuits.
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