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service engine soon light questions and answers
Check Engine Light Question and Answers
Question: 1999 Ford Expedition. We tested the SRS. The malfunction Indicator
blinked Code 52. Checking DERM we found some water at that area and we thought this
the cause of the fault. After replacing DERM, the vehicle operated without trouble
- but only for two weeks. After this period, our client came again for service:
MIL of SRS blinked trouble Code 12. The fuse of the system has blown. Fitting in
a new fuse the MIL blinked Code 52 again. We didn't find any trouble as before.
Shall we replace DERM again? What would be the cause of the repeated fault? Can
you give us some idea? (Unfortunately, we haven't DRB for this model because there
are only a dozen Expeditions in our country) Awaiting for your reply - Regards from
Hungary, Budapest
Answer: You should replace the DERM again. However, before you do, check
the wiring looms in the engine compartment for damage or bad connections. Also,
check the ground connections for high resistance. Either a shorted or a bad connection
will overload the 12 volts causing the failure you described.
Question: 1998 Chevy/Spectrum 4 cyl mileage: 86,000. Same as Isuzu I-Mark
Have 1986 Chevy Spectrum, 4 cyl, AT-AC, 86k miles. Local service centers stumped.
Been checking off and on since 12/18/00. We have emissions requirements here and
vehicle was waived two years ago. Would not pass test and diagnosis unknown. State
will not allow a waiver two periods in a row. In last year, had radiator, heater
core, plugs, wires, distributor, cap, rotor, fuel & air filter, O2 sensor all replaced.
Vehicle scoped and no answer to symptom of wanting to shut off while idling at a
stop. Engine seems to choke & tries to shut off. When given a little gas, it revs
up nice and smooth. Only other symptoms are an intermittently blinking check engine
light that shows no trouble code and engine runs cool, even though thermostat replaced
with 195-degree unit. Was told to go buy another car that passes emissions.Answer: Your problem may be an idle speed control motor or possibly a
partially plugged catalytic converter. The blinking check engine light would indicate
a stored fault code. Retrieving the codes of your make and model of car is difficult.
Question: 1998 Cadillac Eldorado mileage: 82,000. Recent engine problem
said to be MAYBE a MAP sensor as car stalls with Fuel Rich Mixture and gives a Code
of 21. Changed TPS and idling improved but erratic (sometimes) stall occurs proceeded
by "Check Engine Light"! Spent thousands of dollars on this engine since day #1
- has NEVER run correctly - believe it to be and have spent lots more restoring
car as my wife loves it! #1 Do you believe it is as simple as MAP sensor (current
crisis)? And #2 where on earth can I buy one? Have tried! #3 Can I get this lemon
engine to EVER run right? Can a speed shop do it? Tell me - please! Can you explain
why this year's engine has been such a problem? Cadillac was NEVER able to make
it run smoothly and correctly! Remedies?
Answer: The coolant temperature sensors were not the best. The same type
of sensor is used for the air temperature. Replacing both of them at the same time
is a good practice. Also, check the fuel pressure regulator. We do not believe the
MAP sensor is your problem.
Question: 1999 Mustang Cobra mileage: 87,000. I have been going back and
forth with this Ford dealer who couldn't seem to install my clutch properly. After
three attempts, the second two at no charge to me, the clutch seems to be working
fine and the car seems to run ok. However, soon after I picked up my car the third
time and drove to my destination. My check engine light comes on and stays on. When
I turn my car off and back on it goes off, but will come back on and stay after
driving some variable amount of time. Does a clutch replacement require any interaction
with sensors or any component that affects the computers' readings that may cause
the check engine light to come on?
Answer: Your car is equipped with four oxygen sensors that are close to
the transmission. If one of them was inadvertently not reconnected, it will light
the check engine light.
Question: 1993 Chevy c10 pickup 2wd mileage: 272,000. When I am driving on a
road with a lot of hills or curves sometimes my service engine light comes on It
seems to only effect the brake system as there is no noticeable engine change, except
when I shut the motor off it will keep running for a few seconds. After about 5
minutes, I can restart with no problems. I have also had the light come on at highway
speeds with the same effect. I took it to my mech. and he tried to use his analyzer
on it but it would not compute. The message came back no connection possible. He
said he would have to replace the computer to find out what the problem was. This
seems to be an expensive way to find the problem.
Answer: When your car is in use several electronic components are used.
Making this particular repair is one of the most dreaded. Your problem could be
from your ignition switch to a fuel pump, about 15 different things can cause this
condition.
Question: 1989 Chevy Corvette mileage: 67,000. I got a code 34 on my computer,
went in had another MAF put in, car ran fine for 3 days with no codes. Suddenly
code 34 is back...what could cause this.
Answer: The catalytic converter may be the cause of the failure code for
the mass airflow sensor (MAF). If the converter is partially plugged, it backs up
the exhaust, which affects intake manifold vacuum. The airflow into the engine is
then affected resulting in your code 34.
Question: 1996 Honda Civic mileage: 155,000. I bought a liquid bottle
called "fuel up"(for fuel system/anti-rust cleaner) pour half of the bottle in the
gas tank (full), as recommended on the instructions. Next day I drove my car
for about 15 minutes and the "check engine" light came up, I stepped on the gas
pedal and the car turned off, I started the car again and it turned on ok, and the
check engine light went off. I would like to know if it was the fuel system
cleaner I bought or something wrong with the car. Please help. Thank
you.
Answer: There is a chance that having it in the fuel system may have caused
a malfunction in the oxygen sensor lighting your check engine light.
Question: 1999 Nissan Sentra mileage: 121,000. The "Check
Engine Soon" light came on the other night, but the car seems to run fine.
One of my friends says it's probably just that I need more anti-freeze or coolant.
Is this right? This is Michigan and its about 10 degrees F during the night.
Answer: The “check engine” light will “light” when there is a malfunction
in the engine management system. The fault code is then stored in the computer.
The computer must be scanned to retrieve these stored faults to pinpoint the malfunctioning
component.
Question: 1997 Chevy Lumina 3.8L mileage: 98,520. I have been getting
a service engine soon light for some time and haven't been able to find a cheap
code scanner for this vehicle. I bought a Hayes computer code trouble-shooting manual
and it tells me to put a jumper in the A and B slots on the ALDL to ground the diagnostic
terminal. The only problem with this is that there is nothing in the B slot;
it just goes all the way through the back of the socket. This ALDL has only
3 terminals being used in it. There is one in the A position and one below
it. According to the book there should be a B terminal right next to the A.
This car is OBD1 certified and I guess what I need to know is what is the proper
why to jumper out the ALDL to retrieve the codes or do I have to take it to a service
shop to have it done on a diagnostic machine. I would greatly appreciate your
help in this matter.
Answer: Your car cannot be jumped between the A and B slots to read the
codes. 1993 was the last year where this could be done. Your car has to be
scanned with an OBD II scanner.
Question: 1997 Saturn SL2 mileage: 118,000. If I change the O2 sensor
(on the exhaust manifold), how can I re-set the diagnostic computer codes so the
"Check Engine" light will go off? Also, the J.C. Whitney catalog lists a universal
'one-wire' oxygen sensor; will this work on my Saturn? Thanks!Answer:
The check engine light on your car must be reset with a computer scanner.
In addition, if your car is equipped with a one-wire oxygen sensor, then the one-wire
sensor should work. However, your car has a four-wire sensor.
Question: 1992 Hyundai Accent mileage: 155,000. Ok my Hyundai Excel
was not treated as well as it should have been. I believe the one of the cylinder
piston skirts cracked. It was time for a new engine. My mates
and I pulled out the old one. Placed in a reconditioned engine... much better.
But. Initially the timing was retarded too far and therefore the engine backfired.
I drove about 100 miles with the engine like this. I got my hands on a timing
light and was just about to tune it when the CHECK ENGINE light came on.
My manual says that this indicates a problem with the exhaust system. I cannot
detect any such problem and the engine appears to be working perfectly (Once I fixed
the timing). What do I need to fix? Did the backfiring just fry
some environmental circuit? I have heard third hand of an Excel having the
same light turn on, nothing wrong with it. Kept on going for years.
Any help would be appreciated.
Answer: The light can be extinguished and fault codes cleared by
disconnecting the battery for several minutes. If there is a malfunctioning
sensor or switch, it will relight the light. The “check engine” light
will “light” when there is a malfunction in the engine management system.
The fault code is then stored in the computer. The computer must be scanned
to retrieve these stored faults to pinpoint the malfunctioning component.
Question: 1998 Chevy 1500 Truck 4x4. I just bought a used Chevy 1500
4x4. I was wondering if there is one of those levers or buttons that you have to
push in to turn off the service engine light after you have changed the oil.
If you know where this magical button is could you email me back, thanks a lot.
Answer: There is no magic button for the service engine light.
If there is a malfunctioning sensor or switch, it will relight the light.
This is good you will know for sure that something is wrong. The “check engine”
light will “light” when there is a malfunction in the engine management system.
The fault code is then stored in the computer. The computer must be scanned
to retrieve these stored faults to pinpoint the malfunctioning component.
Question: 1994 Buick Regal mileage: 105,000. The check engine light
comes one frequently but with no certain pattern. We asked our technician
about this indicating there was no change in "functionality" of the car when the
light comes on and he said not to worry about it. I have also been told this
is a common trait with this vehicle. What is your professional opinion?
Answer: When your car is in use several electronic
components are used. Making this particular repair is one of the most dreaded. Your
problem could be from your ignition switch to a fuel pump, about 15 different things
can cause this condition.
Question: 1990 Buick Electra Park Ave. mileage: 124,000. Car runs
great. Speedometer does not always work. When it does not work and I am climbing
a hill the "check Engine" light comes on. As soon as the speedometer starts
to move again, the light goes off. Sometimes the light will stay on for 30
minutes, but when the speedometer moves, it goes out. Immediately car runs
great. If I am going with traffic say 55 - 60 the speedometer reads 25 or
so (sorta got to be careful about getting out at that speed Eh?) I get a code
24 from flashes on dashboard when asking computer about "check engine" deal.
Problem is: the guys at the GM dealer say that there is no VSS on that year and
model. And besides when I do find it, if I do have one on the car. Is
it behind the speedometer or on transmission somewhere? Thanks for any help.
Answer: Your problem may be caused by the cruise control transducer.
The speedometer cable from the transmission goes into the transducer and back out
to the speedometer. It is more likely than not that the transducer is
causing the problems you are experiencing. The vehicle speed sensor should
be located in the rear of the transmission.
Question: 2001 Ford Escort 1.9l Fi mileage: 75,000. I am an ex GM
mechanic, is there anyway to read and clear fault codes on this vehicle without
a scanner?
Answer: A scanner is necessary in order to read and clear the codes
on late model Fords.
MORE: Check engine or
service engine soon light questions and answers
Repair Topics / Check Engine
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