"Dr. Gizmo"
By Phil Arendt
Check
Fuse First
Question 1I have a 2001 Toyota Camry with 169,700 miles. I'm the original owner and the vehicle maintenance has followed the recommended factory schedule.
About 2,000 miles ago, the check
engine illuminated. The car runs fine and I have noticed no
performance related issues. I had the codes interpreted by an
independent repair shop. They said multiple codes were present - air/fuel
sensor, catalytic converter or leak in exhaust system. They suggested
replacing the air/fuel sensor first and moving on from there if the check
engine light illuminated again.
I ordered the air/fuel
sensor from an online parts dealer and replaced it myself since the sensor
location was very accessible. Unfortunately, the check engine light
illuminated again. I had a local auto parts dealer with a code reader
diagnose the code. Only one code is present P1135 indicating trouble in
the first air/fuel sensor heater circuit response on bank one. The probable
cause is an open or short circuit condition or poor electrical
connection. I unhooked the electrical connection on the air/fuel
sensor and re-connected to verify the connection is sound. I purchased an
aftermarket air/fuel sensor and wonder if this is causing the problem.
I don't live in an area with
emissions testing so I could just continue to drive the car but if something
else happens I won't know because the check engine light stays on. Do I need to buy a Toyota air/fuel sensor to
get the engine light to turn off? Do you have any other
ideas? Thanks for your time.
J.G., email
Answer 1
Consider checking fuses in
the engine compartment fuse panel and passenger compartment. Sometimes a fuse pops when a sensor
fails.
If you have a digital volt/ohm
meter test the circuit using help from a repair manual. If voltage is within specifications make sure
nothing impairs the sensor’s ground circuit.
Sometimes corrosion impairs the ground at the sensor threads. Also, if you applied an anti-seize compound
or thread sealer to the threads the ground might be impaired. Correct these conditions as necessary.
If everything seems okay and
no other malfunction codes are present in the engine control module,
installation of an original equipment sensor might be a last repair.
Electrical Trouble Hampers
Transmission
Question 2Suddenly, the automatic transmission in my 2002 Chevrolet Cavalier stopped shifting and the check engine light turned on. It has 115,000 miles. It feels as though it is stuck in first gear.
I went to a repair shop
where a mechanic did a test on the computer.
He retrieved three codes. They
are PO753, PO758 and PO1860. He said he
does not overhaul transmissions. All he
can do is replace it with a junk yard unit or remanufactured transmission.
After his work I drove
slowly home. My car is in great
condition. It has never given me any
trouble. I would not hesitate to fix it. Do you think it is necessary to replace the
transmission? S.R.S., email
Answer 2
Not yet. This malfunction
truly may be an electrical issue requiring nothing but a wiring repair.
Since your technician does
not perform transmission repairs consider taking the vehicle to a shop that can
handle all aspects of transmission repair.
A technician with the tools and expertise will test circuits, cycle
solenoids and perform pressure tests that will result in a thorough diagnosis
of the cause of the trouble. If all that
is necessary is a wire repair you will save big bucks.
A Clean Sensor Could Cure
Trouble
Question 3I have a 2007 Ford Expedition with a 5.4-liter engine that suddenly idles too low. I went to a repair shop where they checked for trouble codes. One code came up that did not offer any clues. The mechanic working on the vehicle said the code is erroneous. They suggested that I drive the vehicle for a few days suggesting that more codes might show up that will be helpful.
The engine runs fine except
that it idles around 375 RPM and feels as though it will stall.
Do you have any idea what causes
this problem? D.M., email
Answer 3
Sometimes tests of the
engine control module reveals a code for which there is no definition. As for the idle concern, this might be cured
by cleaning the throttle body or mass air flow sensor. When you return to your shop, if no other
codes pop up ask them to consider this suggestion.
Open Window During Heavy
Rain Ruins Computer Module
Question 4Recently, I purchased a 2008 Mercedes-Benz S63 AMG. During a recent heavy rain storm I inadvertently left the passenger window open and a great deal of water filled the floor. I bailed out the water and upon starting the car the warning light for the suspension was on and the car was riding higher than usual.
A buddy who is pretty good
when it comes to auto repair found a module that was under water on the
passenger floor. We removed all the
water. He dried and cleaned the module
plug but this made no difference. A few
days later he installed a new module but it did not correct the trouble. Now he thinks it needs programming but I
didn’t want to take the car to a dealer.
Is it necessary to program
the module or is there something else causing the trouble? A.M., email
Answer 4
You’re lucky only one module
failed due to the rain water. Also, now
it’s time to prevent the formation of mold, mildew and corrosion by removing
the carpet so it can thoroughly dry.
I’m not sure which module
your buddy replaced but I suspect it is necessary to program it. If it is the Active Body Control module,
before you visit your favorite repair shop you might try programming it with
the remote key fob. If my suspicions are
correct pressing on the lock and unlock buttons on the fob four times might
program the module and your troubles might be over. If not, it’s time to seek the help of your
favorite shop technician.
Diagnosis Hindered By Lack
Of Diagnostic Resources
Question 5In the morning when I first start my 2001 Ford Escape with a 6-cylinder engine it sputters, coughs and stalls. Once it warms up a little it runs fine. My shop has replaced the idle control, spark plugs, ignition coils, intake gaskets and fuel filter all to no avail.
One time a mechanic came to
my house in the morning to check the car.
He found some unusual readings during tests but was unable to pinpoint
the cause of the trouble.
When my shop does tests
there are no trouble codes. They have
done several tests on sensors but they pass.
They suggest that I leave the car overnight so they can run tests when
the engine is cold but I desperately need my car. Can you help?
W.V.W., email
Answer 5
It would be interesting to know what the technician was testing when he found unusual readings. It might be worth a try to replace the part he was testing when results were out of specifications but the majority of technicians do not replace parts unless they are absolutely sure a part has failed.
To cure the trouble consider
leaving the vehicle at your shop overnight so a technician has an opportunity
to perform tests when the engine is stone cold and when he has all the
resources and tools available to do proper testing. The fact he came to your home is commendable
but he did not have all the diagnostic resources of his shop. Perhaps your shop can arrange to have a
rental car ready for you when you leave your vehicle with them.
Wheel Sensor Hidden From
View
Question 6Occasionally, the ABS light turns on in my 2000 Pontiac Grand AM. It has a 6-cylinder engine and 150,000 miles. I took the vehicle to my local shop that has been servicing the car for several years. Testing found a code that indicates a problem at the front passenger wheel. He checked the wires and everything seems ok.
What does the wheel have to
do with the antilock brakes? W.D., email
Answer 6
The wheels on your car go round and round and there is a sensor at each wheel that sends signals to a computer that determines how fast the wheels are spinning. This information is used by the traction control and anti-lock brake system to assist you in controlling braking and traction.
More than likely the sensor
on the right front wheel has a fault.
Since this sensor is part of the wheel hub, the hub needs
replacement. The hub is the part on the
drive axle that the brake rotor, tire and wheel are secured to. Since your technician is not sure if the
sensor has a fault, it’s likely an intermittent condition. It’s also likely he does not want to replace
the part until he is absolutely sure.
At this point you can drive
the vehicle until the warning light turns on a frequent basis or steadily. Or, your technician can replace the sensor
and hub assembly with a reasonable degree of certainty that doing so will
repair the trouble.
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 mailto:drgizmo@hotmail.com. 07/22/2013 ® DR. GIZMO © 1989 - Present
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