Repair Topics / Warning Lights / Warning Lights-2 / Warning Lights-3

• Why is my service engine soon light on?
• Why is my check engine light on?
• How to test a thermostat
• How to reprogram a key fob remote control

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Car Warning Lights - This category contains featured questions as examples. They relate to most vehicles.

Question: 2002 Toyota Camry, miles: 67,990 I had the battery in my car replaced. After starting the car with the new battery installed, I noticed the air bag indicator light was flashing. This warning light had never come on before. Recently at my 90,000-mile maintenance check, I had the dealer check the air bag system, and he told me there was an open circuit in the air bag control system, which would cost $900 to repair. I haven't had this 'problem' fixed. Forward to this week. I had my starter replaced, and today when I picked it up and drove off the lot, I noticed the maintenance indicator light was on. Again, this light had never come on before, and now after having my starter replaced it does. My owner's manual states that this light indicates a potential emission control problem. I took it back to the mechanic to check into this, and he checked the 'coding', whatever that is. He determined it was a hard code, and they couldn't reset it. He suggests I take the car to the dealer to check, which I'm sure will result in another $1000 repair recommendation. It seems too coincidental to me to suddenly have problems with the air bag and emission control systems, after having these unrelated repairs performed. Do you have any ideas related to what could be causing these warning lights to come on, and how I can have them reset without having needless and expensive repair done? I would appreciate any ideas. Thanks.

Answer: It sounds like the battery was installed with the battery cables backward for a brief time, causing the system to short circuit.

Question: 2000 Chevy S-10  mileage: 50,000.  I have a Chevy S-10 with very low mileage.  It has no AC.  It is in excellent over all condition.  Recently I began to have acceleration problems.  It runs great when cold and sometimes even when heats up.  But most of the time, once it warms up, it pops and sputters on acceleration.  I can't figure it out.  Fuel pump weak after warm-up!  Fuel regulator valve!  Electrical!  I hope you can help.

Answer: Your car is ready for a major tune-up including auto parts like: spark plugs, plug wires, fuel filter and air filter.  Also, perform a fuel pump pressure test just to be safe.

Question: 2002 Toyota Camry, miles 65,000: I have been to the shop twice for the check engine light coming on. $60 bucks a shot. Each time it was an O2 sensor, first one before the catalectic converter then the one after went. Now the light is on again.

Answer:   This is difficult because the computer can't detect a problem, your car thinks everything is ok. In reality what is happening is the electrical component inside the MAF sensor becomes contaminated by the impurities in the air (heavies) These containments imbed themselves to electrical component that senses the air flow causing the sensor to be slightly off, but not enough to trigger the MIL (malfunction indicator lamp). Replace the MAF sensor with a new sensor and you're problem will go away, plus your car get better mileage and performance. (Mass Air Flow MAF sensor or Air Intake Sensor AIS, depending on manufacture. It does the same thing with different names).

Question:   2001 Hyundai Sonata, mileage: 98,000 Thanks for taking the time to answer my question. It is very hard to start. The only way to start it is to start it and not give it any gas for a minute or so. It takes-6 tries before you can get it to stay running. It has a service engine light on the dash and disconnecting the battery cable has not eliminated the light. Once started it runs fair but it cuts out as if it is running lean. the problem seems to be getting worse. We do not have a local dealer. Any input you can give me will be appreciated.

Answer:   The service engine light indicates a problem in the computer controlled engine management system. Scan PCM for trouble codes and repair as needed.

Question: 1999 Lincoln Continental, mileage: 120,000. The DCL indicator came on in the diagnostics screen. What is it, what does it mean, and how do I fix it?

Answer: The DCL indicator you refer too is short for "driver caution light." Below the diagnostics screen should be a small button to press. The screen will then tell you what the problem is for example, tail light bulb out, parking light failed, etc. Your owner�s manual should have more information on this system.
 

Question: 1999 Chevrolet Tahoe, mileage: 128,000. My coolant light comes on sometimes. Can I just add coolant or do I have to have it flushed?

Answer:   The coolant light normally comes on when you are low on coolant. Adding coolant will extinguish the light. If your cooling system has not been serviced (changing the coolant), it should be done now. A cooling system needs to be serviced every two to three years.

Question: 1999 Mitsubishi Montero V6 mileage: 82,000.  I was driving my Montero today and the "Check Engine" light came on. I checked the engine over and found no problem.  It wasn't overheating, it had plenty of oil and antifreeze, the oil pressure was okay, and there was no visible problem.  Do you have any idea what would cause the light to come on and stay on?  Any suggestions?

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: 1991 Oldsmobile Alero, mileage: 72,000.  1. Service engine light is on.  I did the paper clip thing.  Code is 41.  Does that mean the cam sensor is bad?  2.  Temp light goes on at about 80 mph if I back off the gas it goes out in about 45 or seconds or so.  Water pump going bad?

Answer: The cam sensor may be faulty or a stretched or worn timing chain would also give you a code 41. We do not think the water pump is at fault.  A partially plugged radiator may be causing your problem.

Question: 1989: Pontiac Grand Prix, mileage: 79,000.  My car is having problems idling, it won't, It stalls.  The service engine soon light comes on.  I got the diagnostic code off the car, it flashed code 33.  I was wondering if you could give me a hint on what could be wrong.

Answer:  Code 33 is a map sensor problem.  Check the engine for vacuum leaks.  Check the exhaust for blockage (catalytic converter).  The map sensor may be faulty.

Question: 1987 Ford F150  mileage: 150,000.  The check engine light comes on intermittently with a code 77 (#3 EGR solenoid).   The EGR has been changed and all connections checked. I don't see any carbon or anything which could have held it open. Is there anything I should look for?

Question: 1988 Ford F250, mileage: 120,000.  Thanks for any help.  I will try to be specific.  I purchased the truck about a month ago.  The "check engine" light comes on after being driven for 5 or 10 miles from a cold start.  EEC-IV codes were checked: Key On Engine Off test gives a code of 11 (system pass).  Continuous code (stored memory) issues 41 (system indicates lean) and a 34 (EVP voltage above closed limit).  I have recently replaced the EGR valve, the EVP sensor, and the oxygen sensor in an effort to correct this problem with no success.  Sometime before that, the MAP sensor was replaced.  The condition of the spark plugs and the engine temperature gauge do not indicate that the mixture is lean, at least not severely.  I set the timing (SPOUT shorted) to 10 degrees BTDC.  Except for this warning light, the motor seems to be running pretty smooth.  It has an automatic transmission (no overdrive) and air conditioning.  Any help would be greatly appreciated.

Answer:   Check the fuel pump pressure and replace the fuel filter if not recently done.  Try injector cleaner in the gas tank if the problem persists.   The fuel injectors may need to be replaced.

Question: 1988 Chevrolet S10, miles: 97,000 The truck was purchased for our son has new engine. The check engine light is on and the code reads 41 and 24 we know the speed sensor but what could the 41 be for it is not in the book? We had someone look at it and he mentioned distributor reference voltage and hall effect something called HEI. Make some suggestions please and if you�re wondering I am not the one doing the work thank goodness.

Answer:   First scan PCM for trouble codes and repair as needed. IF no codes are present then try testing the ignition coil output.

Question: I recently replaced the air intake on my car with an after market model, and during the installation, I started the car without the Mass Air Sensor wire installed. Now, my check engine soon light is on, and I was wondering if there is any way to reset this.

Answer: The malfunction indicator light cannot be reset without an OBD II scanner tool.

Question: 1999 Acura Integra, mileage: 81,000. I bought the car at 78K miles. It seems in excellent condition. I changed the oil at 81K and since then the oil light flashes intermittently, although oil is full and car drives excellent, with no engine noise. I suspect a sensor but am concerned. Any ideas or help will be appreciated.

Answer: You may have low oil pressure. With engine the stopped, remove the oil pressure-sending unit. Replace with a temporary mechanical oil pressure gauge. Start the engine and note pressure at idle and at 2000 RPM. At 2000 RPM, the pressure should be approximately 40 to 50 pounds and about that at idle. If you do not get these results, you may have internal engine problems. One possibility is a stuck oil pressure relief valve.

Question: 1989 Dodge Ram 1500 4x4, mileage 78,000. The truck occasionally has periods of poor acceleration and hesitation, sometimes stalls and has poor gas mileage - 21 mph. The car had a complete tune-up 3 months ago; the symptoms got better but did not go away. A red CHECK ENGINE light comes on occasionally. The poor performance happens when the light is on. Is this something I can fix myself or do I need a mechanic?

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 Ford Ranger, mileage: 149,800. The check engine light came on in the truck. I popped the hood, looked at it, and saw that this thing had come disconnected, which is located next to where you pour the oil in. (Sorry for my lousy description, I don't know what it is.) So, I reconnected it, but the check engine light remained on. I took it to the dealership today and they said the oxygen sensor had gone out, plus I needed to have the fuel injectors cleaned, desludged and replace the fuel filter. I went ahead with the oxygen sensor replacement, but have to wait on the rest because of the cost involved. I was wondering, if you fix whatever it is that makes the check engine light come on, will it automatically go off or does a mechanic have to flip a switch?

Answer: No the light does not automatically go off. Only the OBD II scanning system can reset the MIL (malfunction indicator light, more commonly known as check engine light.)

Question: 1999 Volkswagen Jetta 2.0, miles: 98,000 How do I get my check engine light to go off? It comes on about every three months then goes off. It happened three times in three years.

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 Dodge Pickup, 2500, mileage: 157,000. The check engine light came on so I took the pickup to the dealer and they reset it. They said the purge control solenoid was the problem. The light came on again a few days later. Is there a way I can reset without taking back to a mechanic?

Answer:   It sounds like the dealer missed the problem. First scan PCM for trouble codes and repair as needed.  Only the OBD II scanner system can reset the MIL (check engine light).

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Repair Topics / Warning Lights / Warning Lights-2 / Warning Lights-3