Why is my check engine light not coming on after first turn of the key and does this mean my computer is dead
My miata was running fine parked it for the night the next day it will not start. Turn the key on all the check lights come on except the check engine light,theirs no spark no fuel pump. It has an old battery but it still turns the motor over good just checked batt. 13.06volts . I think my computer controll is dead (ECU , ECI) im not sure what to call that black box.
My car has 182724 miles.
My car has an automatic transmission.
Experienced mechanics share their insights in answering this question :
Hi there. It is possible that the ECU is damaged; however, it could be a simple problem like a damaged fuse, damaged electrical relay or problems with the dashboard itself. It’s best to have a professional mechanic to complete a check engine light inspection. This will allow the mechanic to attempt to access the ECU with the scanner. If it connects, then the issues are much easier to resolve. Replacing an ECU can only be done by a dealer; or authorized Mazda mechanic, which can get rather expensive.
How to Identify and Fix Common car Problems ?
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the check engine light should come on when key is turned to on. cluster does a bulb check every time key is turned to on. if it is not coming on,then it could be a fuse or the bulb its self is burned out in the cluster. check owners manual,and or fuse box lid/cover for fuse location first.
A check engine light will shut itself off if the condition that caused it is remedied. So, if your converter is marginal, and you did a lot of stop-and-go driving, which creates high demand for the converter, that may have turned on the check engine light.
However, if there`s a problem, the light will come back on as soon as the computer runs the test that caused the light in the first place. It might happen right after you turn the car on, which might make it seem like you can`t clear the check engine light. Or it might take a couple of days to come back.
There is no fuse for the check engine light. If it`s not working (i.e. if it doesn`t light up as part of the ignition sequence), chances are it was deliberately deactivated to hide a major issue and dupe you, the buyer, out of more money.
In short, yes; it`s possible to diagnose a problem with a vehicle even if the check engine light does not illuminate.
It`s absolutely normal for the engine light to turn on when starting the vehicle, and it should go off after a few seconds. Otherwise, if the light stays or turns on when you`re on the road, you can do the following: Check the fuel cap and tighten it if it is loose. If the light goes away after this, you`re good to go.
The check engine light should go off after you drive for several minutes if the light was caused by a loose gas cap. Pay attention to the dashboard after the check engine light experience. If you find that the light keeps coming on, and goes off again once you tighten the gas cap, then your gas cap is too loose.
Press the odometer`s Trip and Reset buttons while turning the ignition key ON. After turning the key ON, release the odometer Reset and Trip buttons to check if the Diagnostic Trouble Code or DTC appears on the odometer display.
Disconnecting your battery and draining the power to cause an ECU reset is one of the most common fixes for a check engine light that won`t go away on its own. Doing so is equivalent to a hard reboot on a desktop computer, which is a standard way to eliminate many common problems.
The check engine light illuminates when your vehicle`s computer believes there is a problem that could affect — or is affecting — your car`s emissions control system. When the light comes on, one or more diagnostic trouble codes are stored in the car`s computer. These codes will stay there even if the light goes out.
Blown Fuse. If you`ve plugged into your car`s diagnostic port and aren`t reading anything, you might think that your OBD-II brain has been fried, but don`t declare it dead yet. The most common reason for getting no OBD code is simply a blown fuse.
If there`s no Check Engine light or any codes that might suggest an O2 sensor related fault, he has no way of knowing if any O2 sensors need to be replaced. The only clues may be a loss of fuel economy, or elevated carbon monoxide emissions (if a pre-OBD II vehicle fails a tailpipe emissions test).
Bad Sensors
One common culprit for this problem is the crankshaft position sensor, which measures the position and speed of the crankshaft. The computer uses the information from this sensor to know when to fire the spark plugs. If the sensor isn`t working, the spark plugs won`t fire, keeping the engine from starting.
Bad Gas, What are the Symptoms? If you`ve inspected the gas cap, the problems you are having may be due to contaminated fuel. If a car, truck, or SUV has trouble starting, will not accelerate, or just is not running smoothly, then it`s possible you just have a contaminated tank of gas.
Many manufacturers recommend tightening the fuel cap until it clicks three times, which is just a random number to make sure the cap is tight. At this point — even though the engine will run fine — it would be best to bring the car into have it looked at.
The easiest method to reset the check engine light is to drive your car as you normally would and let the light turn off naturally by itself. If it hasn`t turned off after three days, turn the car on and off three times consecutively.
Can I Check My Own Light? You can. All you need to check your light is an OBD-II reader, which can pull codes that help you find out what`s wrong with your car.
Car Scanner ELM OBD2
Car Scanner ELM is an easy-to-use app that allows you to view any DTC`s (Diagnostic Trouble Codes) that your vehicle might have accumulated. This app is one of the best OBD2 apps for Android as well as iOS.
It really depends on the ECU, the car itself, and what year car it is. Also, it depends on what is being relearned. Some things, like short term fuel trims can be learned in as little as 20 miles. Other things like long term fuel trims will take longer, maybe 80 to 100 or more miles.
To make sure the check engine light does not reappear, it`s recommended that you drive your car 30 to 100 miles. This enables the vehicle`s “Drive Cycle” to reset, as the various sensors need time to recalibrate.
Engine misfires, rough idling and hard starts can all be traced to a clogged engine air filter. The dirty air filter restricts the air supply to the engine causing unburned fuel to form a soot residue that accumulates on the spark plug.
Incorrect filter installation or installing the wrong filter can leave your engine open to dirt and debris. When the engine`s air intake is not completely covered by a filtering element, extensive damage can occur.
Relevant Questions and Answers :
the most relevant questions and answers related to your specific issue
Why is my check engine light not coming on after first turn of the key and does this mean my computer is dead
ANSWER : Hi there. It is possible that the ECU is damaged; however, it could be a simple problem like a damaged fuse, damaged electrical relay or problems with the dashboard itself. It’s best to have a professional mechanic to complete a check engine light inspection. This will allow the mechanic to attempt to access the ECU with the scanner. If it connects, then the issues are much easier to resolve. Replacing an ECU can only be done by a dealer; or authorized Mazda mechanic, which can get rather expensive.
I am not getting any power when I turn the key to the on position. there is no dash lights only check engine lite comes on.
ANSWER : The problem of having erratic electrical issues with this year Bronco they have problems with the ignition switch losing contact. You should check and replace the ignition switch. When the switch is removed you should check linkage rod and electrical connector for problems and repair as needed along with replace the ignition switch.
Battery light goes on when I start car then turns off, if I rev engine light comes back until rpms go down. Abs goes comes on/off
ANSWER : Batteries can die due to faults in the charging system so ideally a suspected "faulty" battery should be load tested before a decision is made to condemn it. The only exception to this rule is if the battery is already clearly "old" (greater than 5 years) but even then once you put a new battery in, as a replacement for a "dead" battery, you have to comprehensively check out the charging system. Diagnostic Trouble Code P0460 will result in disruption of the dashboard fuel gauge’s ability to accurately report your tank’s fuel levels. The fuel gauge readings may be erratic, or read somewhere off scale. Vehicles equipped with a low fuel warning light feature may also suffer from erratic low fuel warnings in the event of a code P0460. Unless the P0460 code has been reported alongside other trouble code, all of the vehicle’s essential systems should otherwise function normally. I would recommend that you request a check engine light diagnostic to first resolve the fault causing the P0460 code to set. The check gas cap light warning light could be due a faulty gas cap and/or small leaks in the EVAP system.
Traction light/reduced engine power and check engine light coming on
ANSWER : Hello. From what you describe, it would appear that your vehicle may be experiencing some sort of intermittent wiring or sensor issue. If the problem occurred again after driving over a bump, then it may be possible that a damaged or loose wire is shorting or having contact issues. A common issue that can cause stalling is a faulty crank position sensor or wiring. I would carefully examine the engine for any loose or damaged wires. If the Check Engine Light comes back on, I would recommend having the trouble codes scanned before resetting the computer.
Check Engine Light comes on after starting pickup
ANSWER : Hello there, thank you for asking about your 1992 Isuzu Pickup. A professional will have the correct equipment to read OBD1 codes. Retrieving the diagnostic trouble code(s) is the first place to start when diagnosing your vehicle. Increasing RPMs changes engine load, which can in turn affect many different sensors and components, causing the Check Engine Light to illuminate. The only way to narrow down the options and find the culprit is through in person diagnosis with an OEM compatible scan tool. A certified technician from YourMechanic can retrieve the OBD codes at your home or office.
2006 Ford Mustang has check engine light on
ANSWER : There are countless potential causes for your illuminated check engine light. The mechanic manually turned off the light, but it came back on because the problem has not been fixed. The first place to start is retrieval of the stored diagnostic trouble codes (DTCs). These codes serve as a starting point for any further diagnostics a mechanic may perform. Codes will be stored anytime the check engine light is on. Since the first mechanic was unable to fix your concern, I recommend giving the professionals at YourMechanic a call. We offer expert check engine light diagnosis and repair.
Every time I put my key into the ignition lights flicker, radio comes on, and check engine light comes on.
ANSWER : Hi there. There is an issue with the ignition switch when you are turning the key. The tumbler may have worn contacts within the switch causing the lights to flicker and the radio to come on when it is turned off. I recommend seeking out a professional, such as one from Your Mechanic, to help you diagnose an electrical short or loose ground in the ignition switch circuit.
Doesn’t turn on without the Check Engine Light coming on
ANSWER : Hi there. It sounds like the EFI relay is sticking or has resistance internally. This relay provides power to the engine computer. If it delays that power, then there is a delay in the Check Engine Light displaying and the engine starting. The Check Engine Light is there during start up to show that the engine computer is on and powered up. Try replacing that relay and see if the condition continues. I suggest having a qualified technician perform an inspection to avoid replacing unnecessary parts. YourMechanic has several available technicians that can assist you with a starting issue inspection and service your ECM relay as necessary.
