QuestionQUESTION: Hi Roland, my "check engine" light keeps coming on after my car has run about 5 minutes. I checked the oil and transmission fluid, all fluids okay. Can I ruin the engine if I drive it while the light is on? Is it safe to drive? What else could be wrong? It seems to run fine. Thanks for your help. Jennifer
ANSWER: Hi Jennifer,
The check engine light means that something is wrong that will raise the pollution coming from the tailpipe if it is not corrected. It is safe to drive, most likely, and similarly it shouldn't ruin the engine but leaving uncorrected could do harm to other pollution control devices like the catalytic converter. So to avoid an unnecessary repair and help prevent air pollution you would be well advised to find out what is wrong and fix it.
You didnt't tell me the year or model or engine size so I can't tell you specifically how to diagnose the problem. If the vehicle is '96 and earlier it has a self-diagnostic capability you can do yourself with the ignition key. Newer than that there is still on-board diagnostics that may or may not be accessible with the key or may require that an electronic reader to be plugged into a socket under the dash. If you have the newer model you may be able to get a free readout of the code numbers at an Autozone parts store, otherwise a shop should do the readout for around $40.
Try to turn your ignition key: on-off-on-off-on and leave it on, doing that in 5 seconds elapsed time or less. Then watch the check engine light to begin to flash, pause, flash, etc. Count the number of flashes before each pause and let me know what they are. Repeat the counts to be sure you have them accurately. If the light doesn't flash, then watch the odometer window in the speedo to see if it changes to tell you a code number. If no change is noticed then you need the separate reader approach to getting the code number which will tell us what is wrong.
If you get number, write back and tell me what they are, and tell me about the specifics of your car.
Roland
---------- FOLLOW-UP ----------
QUESTION: Sorry I forgot to give you details on my car, it is a '94 Chrysler Plymouth
Acclaim, 4 cylinder, 4 door. Your answer may already help me. My light
went out today after adding transmission fluid. But I want to check on what
you said about the pollution device and the ignition key test. Thanks for the
help and expert advice! I think you are very knowledgeable and
trustworthy....Great job!!! I will let you know if I get a number of flashes on
the ign. key test.. I will refer you to friends and family.....Jennifer
ANSWER: Hi Jennifer,
Thanks so much for the kind remarks. But if you refer me to friends and family, only to those who own Chrysler products, please.
On the check engine light, I doubt that simply adding trans fluid to your transmission, at least on the 2.5L 4 cyl engine, is going to solve the light being 'on' issue. That is because it is not an electronically controlled transmission so it doesn't have any sensors that could generate a fault code. But it is a very good transmission nonetheless and keeping it to the full line (but not overfilled!) is good practice.
But the good news is that because you have '94 model you will be able to do a fault code readout with your ignition key and counting the flashes of the check engine light. So go to it and let me know the results.
Roland
---------- FOLLOW-UP ----------
QUESTION: Hi Roland, I did the ignition key test and it worked! I think it showed a
series of light flashes that went 3--3--5--5. My "check engine" light went t
for three days but came back on today, it is not overheating. I am curious
what you come up with for the code. Thanks. Jennifer
AnswerHi Jennifer,
The 33 code means there is either a short or an open circuit or maybe something wrong with the AC clutch relay's actuation coil. If you haven't had to use the AC lately, it is also called into play when you use the defrost mode on your heater/AC unit. When you do that, the radiator fan should start and you should hear a clunk when the AC compressor's clutch is activated by the AC clutch relay.
So have a friend either push the button for AC or for defrost while you watch/listen to see if the AC clutch springs into action at that very moment. If not, then you need to do some circuit tracing with a volt-ohm meter or try switching the AC clutch relay with one of the other relays that has the same part number to see if the one that was switched either now makes the AC clutch work or if some other function where you plugged in the original AC relay now doesn't work which would say that the AC clutch relay is no good. The AC clutch relay is the middle one on the left inner fender shield, and you could switch it with the starter relay which is the one of the two on the strut tower which is toward the outside of the vehicle. Do that switch after the engine is running (if the relays have the same part number) then try the AC. Then turn it off and try the starter to see if the relay from the AC will work in the starter position. But make sure the two relays have identical part numbers. If switching the relays makes no difference then the wiring needs to be checked, which you can ask me about.
Roland
