How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Ron Z. Your Own Question
Ron Z.
Ron Z., - Toyota Tech -
Category: Toyota
Satisfied Customers: 17797
Experience:  18+yrs experience. State Inspector and Toyota Diagnostics
Type Your Toyota Question Here...
Ron Z. is online now
A new question is answered every 9 seconds

Cel just came on yesterday. truck runs fine (97 t100, 230k

Customer Question

cel just came on yesterday. truck runs fine (97 t100, 230k miles) otherwise. could this be low oil or more likely emissions issue?
JA: When was your last oil change? How many miles are on the car?
Customer: oil is changed every 5 k religously. april of this year.
JA: Tell me a bit more about what's going on so he can help you best.
Customer: only other thing i can add is that the oil pressure indicator is on the low end. that's why i thought it might be oil related.
JA: Are you hoping to fix this yourself?
Customer: yes.
JA: Great! What have you tried so far?
Customer: nothing other than online search and chatting with you.
JA: Is there anything else important you think the Toyota Mechanic should know about your Toyota?
Customer: no. are you a real person?
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Toyota Mechanic about your situation and then connect you two.
Submitted: 4 months ago.
Category: Toyota
Expert:  Ron Z. replied 4 months ago.

When the Check Engine light comes on, this is the on-board computer's way of telling you it sees a problem in one of the monitored systems. Unfortunately, there are literally 100's of parts and sensors monitored in various systems, and to take a "guess" as to which part/sensor in which system is faulty, is virtually impossible. However, if you are not experiencing any drivability issues such as skipping, stalling, shifting problems, etc, then more than likely, the problem is going to lie in the EVAP (emissions control/recovery) system. Very commonly, this could be a faulty, loose or missing fuel cap or even putting fuel in while the vehicle is running can set the light. Check the underside of the fuel cap for any cracks or signs of defects that may keep the cap from sealing correctly. If there are any doubts about the inspection of the cap, replace it. Keep in mind, you will need a cap that meets OE Specs. Those "universal" or "locking" fuel caps sold at after market parts stores do not meet OE specs, and will not seal the system correctly. Check the top of the fuel filler neck for any signs of damage or debris. Check under the vehicle, around the rear areas of the vehicle, looking for any vacuum lines that have dry-rot cracks, holes or loose/missing connections. If these all check out, then the best thing to do at this point is to have the Diagnostic Trouble Codes (aka "p-codes") read from the on-board computer. These p-codes are what is used as a "starting point" for the diagnosis and will tell which part/sensor, in which system, has the fault. There isn't a Mechanic on the planet that can tell you what is wrong with the vehicle just by "looking" at the Engine Light. Every single Mechanic's first course of action WILL be to obtain the p-codes. It's standard diagnostic procedure. Once you get these p-codes you can more accurately and efficiently diagnose the problem and then make the correct repair. You can have these p-codes read FREE (except in California) at any local "big chain" part store (ie. AutoZone, PepBoys, Advanced, etc). If my answer has helped you, please help me and rate using the stars at the top of the page or 'accept' my answer.
If you cannot rate or do not see where to rate, please let me know!
Rating or accepting my answer does not cost you extra. It allows me to be credited for this Q&A.

Expert:  Ron Z. replied 4 months ago.


Related Toyota Questions