Honda Check Engine Light, What Could Be the Problem?

1. Has your car been in the shop for service recently?

2. Have you fueled your car recently?

3. Have you installed any new electronic devices recently?

4. Did your check engine light come on after driving through a deep puddle?

5. Did you possibly overfill your fuel tank?

6. Do you have excessive humidity in your car caused by a water leak?

7. Do you live in a rural area where there are lots of critters?

8. Are there any other warning light illuminated on the dash?

9. Did your car sit for a long period of time without driving it?

10. Were you the last one to drive your car?

2 Bonus Questions

1. Is the car running normal?

2. Is the check engine light flashing?

1. Has your car been serviced recently? If your car has been in the shop recently for service, it’s a good possibility the technician has caused your check engine light problem. I have seen many times where a technician will forget to reinstall a connector to a sensor or has just knocked a connector loose while doing minor service to your vehicle. It is also possible that an electrical connector is not snapped together completely.

Honda places there Oxygen sensor directly below the oil filter on older Hondas, so when you remove the oil filter, oil will spill onto the oxygen sensor. If you have had your oil changed recently, it is possible that when the technician was cleaning off the oil that spilled on to the oxygen sensor, they may have damaged the sensor and caused your check engine light to come on. It’s not likely but it does happen from time to time.

2. Have you fueled your car recently? If you have fueled your car recently it is possible that you may have not tightened the fuel cap enough or maybe you forgot to reinstall your cap, this could cause your check engine light to come on. All Honda fuel caps have a ratcheting device built into the cap to achieve a good seal and also so you cannot over tighten the cap. When tightening your fuel cap, be sure to tighten it enough to hear at least 3 clicks to insure the proper torque. If your check engine light is on, simply check your fuel cap to insure proper torque.

3. Have you installed any new electronic devices lately, or had them installed by a professional? Everyone likes all the new gadgets available for cars these days, like back up cameras, thunder booming stereos, remote car starters, HID headlights and rear entertainment systems to name a few. If you have had a new device installed recently, it is possible that the person installing the device may have blown a fuse or worst, may have tapped into the wrong wire and caused that dang check engine light to come on again.

Check to see if all electronics in the vehicle are working properly (e.g. dash light, 12v power supply, interior lights, etc…) If everything is working properly I would ether check all the fuses with a test light (using a test light or a voltage meter is the fasted way to test your fuses) or return the vehicle to the person who did the work.

4.Did your check engine light come on after driving through a deep puddle? It’s not usual to see something like this but it does happen. If you have been driving for a while on the highway your exhaust can get extremely hot, if you happen to go through an extremely large puddle, it is possible water cooled the oxygen sensor too quickly and cracked the material inside the sensor. The oxygen sensor is located under the vehicle usually in or near the catalytic converter where the temperature can exceed 600 deg. If this sounds like your scenario, take your car to the dealer or your local mechanic.

5. Did you possibly overfill your fuel tank? If your one of those people who like to top off the fuel tank, you need to break your habit if you own a newer Honda. With all the emission laws we have in the United States, car manufactures are trying to lower emissions on all cars and it starts at the pump. The new cars need to purge gas fumes safely at the pump. When you fuel you car, you are forcing fuel into the fuel tank and the vapors need to be filtered first before being released into the atmosphere.

If you over fill the fuel tank in your vehicle, it is possible to damage some emission devices that help purge fuel vapors back into the atmosphere safely and this will definitely cause the check engine light to come on. When you overfill your fuel tank, it pushes fuel into tiny vacuum lines and into filters, which in turn clogs the emission system. This could become very costly because of the parts you damaged but even worst, the time spent diagnosing the problem. Please do not top off you fuel tank, stop filling when the pump shuts off.

6. Do you have excessive humidity in your car caused by a water leak? The most common cause of a water leak is the windshield leaking. If you ever had a windshield replace in your car it could be leaking. It’s difficult to find an expert in windshield replacements, but they are out there. The fastest way to know if your windshield is leaking is by feeling the floor in the front seat area. If you have water on the floor of the vehicle, front or back, it could be the windshield.

If water is noticeable on the front and rear carpet, most likely the leak is in the front of the vehicle, water flows to the back of the carpet on acceleration and because the floor is tapered towards the rear of the vehicle. If the water is only visible on the rear carpet, most likely the leak is in the rear of the vehicle.

If the windshield is leaking it could be dripping on an ECU, (engine control unit) fuse box or any other control unit, this would cause a ECU failure and your check engine light to come on. Water is very damaging to all electronic devices, just drop your smart phone in water and see what happens.

7. Do you live in a rural area where there are lots of critters? Critters can cause all sorts of problems in cars, from horrible smells to chewed wires. If you live or work in an area where mice, rats, chipmunks or squirrels can get in to your car, (which is almost anywhere) they can wreak havoc on your cars electrical systems. Critters like small places to build nests and store food for the winter and for some reason they like to chew wires, in fact, some car manufactures assemble wire harnesses rapped with mice deterrent tape, no kidding. It’s not completely effective but it’s a start. If a critter chews the right wires in your vehicle, it will cause the check engine light to come on and an expensive bill! Replacing a wire harness is daunting and time consuming.

Signs of critters in your vehicle are; bad odors, acorns and nuts stored in the engine compartment, chewed carpeting and blower motor fans for your heating and air conditioning make a loud noise when turned on. Critters are notorious for building nests inside blower motor assemblies, causing all kinds of problems.

8. Are there any other warning light illuminated on the dash? In some cases, a failure with another part or system can cause your check engine light to come on. If there are multiple warning light illuminated on the dash, it could be caused by just one failure, so don’t panic. If you alternator is not charging or over charging, it could cause low or high voltage in the system causing the warning lights to come on. It could be only one problem with multiple lights.

9. Did your car sit for a long period of time without driving it? Cars that sit for a long period of time without being driven are susceptible to a plethora of problems. Critters can have a field day on your car, batteries go dead, flat spots in tires, brake rotors become rusted and cause a pulsation when applying the brakes, pulleys rust and cause belts to squeak, and the list goes on. If you car sat for a while, your check engine light could come on because a sensor or solenoid is stuck or a number of other things could be wrong, so have it checked out by an honest mechanic, they are out there, you just have to find them.

10.Were you the last one to drive your car? If you were not the last one to drive your car and the check engine light is on, you need to start asking questions. Sometimes family members or friends use our cars and possible could spill a soda or something and not tell you. On some Honda's, the ECM/PCM (engine control unit/powertrain control unit) is located below the center console, if you happen to spill a soda or coffee on top of the unit, the sugar will destroy the control unit and that is big bucks to replace, so just be careful with you mocha latte or big gulp.

Bonus question 1. Is the car running normal? If you car is running normal and there is no drivability problem, the problem is not that severe so there is no need to panic. The check engine light is there to warn you of a problem in the emissions system, so call your mechanic or dealer within a reasonable amount of time, in other words, don’t ignore the problem, your car is not running efficiently and your fuel mileage will drop. When your check engine light is on, you car runs on baseline parameters, like auto pilot, and you will not get the fuel mileage the car was designed to get.

Bonus question 2. Is the check engine light flashing? If your check engine light is flashing, you have a serious problem and you really should not be driving your car. When the check engine light flashes, it means you are causing damage to the engine, it's flashing because it's saying STOP!!! Hey Look At Me!!! Get the idea. It’s probably a good idea to call a tow truck at this point; you don’t want to cost yourself anymore money then what already needs to be spent.

If you have a buddy, friend, uncle or cuz that can check the code because they have a scan tool, make sure you write down the code, because if you decide to erase it, you’ll want to know what it was when the light comes back on. It’s good practice for you, and good information to give your mechanic. Unless it a loose gas cap code, the problem will usually come back.

Don’t confuse your check engine light with you maintenance reminder, If you’re not sure, check your manual under warning lights, it can be found in the back of the owner’s manual in the index.

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