Check engine light came on and the owners manual refers to it as a emissions control problem. The vehicle only has 38000 mi. What could be wrong?

when you turn on your ignition to the point before engaging the starter all your warning lights should light up. The Engine Check Light is very obvious, except they throw convention to the wind and show it as 'Service Engine Soon' lamp 'Malfunction indicator lamp (MIL)'.
Page 63 - Section 2-7 Instruments and controls

Malfunction indicator lamp (MIL) If this indicator lamp comes on steady or blinks while the engine is running, it may indicate a potential emission control malfunction. The malfunction indicator lamp may also come on steady if the fuel filler cap is loose or missing, or if the vehicle runs out of fuel. Check to make sure the fuel filler cap is installed and closed tightly, and that the vehicle has at least three gallons of fuel in the fuel tank. After a few driving trips, the lamp should turn off if no other potential emission control system malfunction exists.

http://www.vadennissanservicecontracts.com/owners-manual/nissan/2001-Nissan-Frontier.pdf

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B1318 Battery Voltage Low ABS Module Only applicable for hybrid vehicles. REFER to the Powertrain Control/Emissions Diagnosis (PC/ED) manual. B1318 Battery Voltage Low Instrument Cluster For gasoline vehicles, REFER to Section 414-00 .
For hybrid vehicles, REFER to the Powertrain Control/Emissions Diagnosis (PC/ED) manual. B1318 Battery Voltage Low Power Steering Control Module REFER to the Powertrain Control/Emissions Diagnosis (PC/ED) manual. B1318 Battery Voltage High RCM For gasoline vehicles, REFER to Section 414-00 .
For hybrid vehicles, REFER to the Powertrain Control/Emissions Diagnosis (PC/ED) manual. B1318 Battery Voltage Low SJB For gasoline vehicles, REFER to Section 414-00 .
For hybrid vehicles, REFER to the Powertrain Control/Emissions Diagnosis (PC/ED) manual. B1318 Battery Voltage Low 4WD Control Module For gasoline vehicles, REFER to Section 414-00 .
For hybrid vehicles, REFER to the Powertrain Control/Emissions Diagnosis (PC/ED) manual.
Your best bet , take it to a qualified repair shop.

Light knowed as Emission Control? Its possible that you are talking about Check Engine light, that generally is refer at emission problem. When the light comes on, one or more diagnostic trouble codes (DTC) are stored in the engine control module. These DTCs remain even if the light goes out.


To address a Check Engine Light problem, the DTCs are retrieved and the appropriate troubleshooting information is followed in order to determine the problem.

The four most common Check Engine Light scenarios and what to do:
* The Check Engine Light turns on and off or flickers.
If the Check Engine Light comes on in the city but goes off on the freeway, then the fault is present during city driving conditions. Pay attention to whether or not the vehicle runs or drives any differently when the Check Engine Light illuminates. If vehicle performance does change, drive the car as little as possible and take it to be checked by a service professional as soon as possible. If there is no change in vehicle performance, you can drive home, but have it inspected as soon as possible. In this condition, you run a risk of the vehicle dying or not starting.

* The Check Engine Light comes on and stays on.
If the Check Engine Light illuminates constantly during driving with no noticeable driving or performance problems, there is a permanent fault in the emission control system. When this happens, the computer that controls the emission system usually has a backup program that runs while the fault is present. (These backup programs are often referred to as "limp home" mode programs.) You should get the vehicle serviced as soon as possible, but in most cases, the vehicle will continue to operate, though you run a risk of it dying or not starting.

* The Check Engine Light illuminates, stays on, and there are performance problems.
This means that a vital component of your emission control and engine management system has a serious problem. It usually involves a component or system needed for the vehicle to run at all. In most cases, drive the vehicle as little as possible. In many cases, the vehicle is not safe to drive at all -it could stop or stall out at any moment. It is best to pull over to a safe place and have the vehicle towed to an automotive diagnostician for a thorough inspection and repair.

* The Check Engine Light light comes on and blinks in a steady pattern while driving.
Don't confuse this steady pulsing of the Check Engine Light light (usually one or more flashes per second) with a flicker (see above). The Check Engine Light may stay on steadily or it may flash when the vehicle is accelerated. This is very serious. There is a severe failure of the emission control system that is causing the engine to misfire to the point that the catalytic converter is damaged each time the Check Engine Light flashes. It may mean that the catalytic converter is overheating to the point that it will glow red or, in extreme cases, start a fire on the underside of the vehicle. Immediately pull over to a safe place and have your vehicle towed to an automotive diagnostician for repair. Vehicles can be severely damaged and even destroyed by fire if this condition is ignored for too long.

Hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.

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Go to an Autozone, Oreilys, or Advance parts store for a free scan. Then buy a part for yourself or price a repair at a shop. You will know what is wrong and can price out the repair.

Hi Bob:
The 'check engine' light is reserved only for powertrain problems that could have an impact on the emissions systems

The Four Most Common Check Engine Light Scenarios and What to Do
The Check Engine Light turns on and off or flickers.
If the Check Engine Light comes on in the city but goes off on the freeway, then the fault is present during city driving conditions. Pay attention to whether or not the vehicle runs or drives any differently when the Check Engine Light illuminates. If vehicle performance does change, drive the car as little as possible and take it to be checked by a service professional as soon as possible. If there is no change in vehicle performance, you can drive home, but have it inspected as soon as possible. In this condition, you run a risk of the vehicle dying or not starting.

The Check Engine Light comes on and stays on.
If the Check Engine Light illuminates constantly during driving with no noticeable driving or performance problems, there is a permanent fault in the emission control system. When this happens, the computer that controls the emission system usually has a backup program that runs while the fault is present. (These backup programs are often referred to as "limp home" mode programs.) You should get the vehicle serviced as soon as possible, but in most cases, the vehicle will continue to operate, though you run a risk of it dying or not starting.

The Check Engine Light illuminates, stays on, and there are performance problems.
This means that a vital component of your emission control and engine management system has a serious problem. It usually involves a component or system needed for the vehicle to run at all. In most cases, drive the vehicle as little as possible. In many cases, the vehicle is not safe to drive at all - it could stop or stall out at any moment. It is best to pull over to a safe place and have the vehicle towed to an automotive diagnostician for a thorough inspection and repair.

The Check Engine Light light comes on and blinks in a steady pattern while driving.
Don't confuse this steady pulsing of the Check Engine Light light (usually one or more flashes per second) with a flicker (see above). The Check Engine Light may stay on steadily or it may flash when the vehicle is accelerated. This is very serious. There is a severe failure of the emission control system that is causing the engine to misfire to the point that the catalytic converter is damaged each time the Check Engine Light flashes. It may mean that the catalytic converter is overheating to the point that it will glow red or, in extreme cases, start a fire on the underside of the vehicle. Immediately pull over to a safe place and have your vehicle towed to an automotive diagnostician for repair. Vehicles can be severely damaged and even destroyed by fire if this condition is ignored for too long.

Once the repair is completed, a technician will reset the "Check Engine" light. If you have necessary skills, a good scan tool and the repair manual, you can diagnose the problem yourself.

Hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.

Thank you for using FixYa, have a nice day.

Why my Check Engine/Service/Check Engines Soon light comes on?
The engine computer or PCM/ECM
All modern vehicles have a computer or the ECM (Electronic Control Module) that controls the operation of the vehicle powertrain (the engine and transmission). The main purpose of this is to keep the engine running at top efficiency with the lowest possible emissions. With constantly growing demands for better fuel economy and new strictest emission regulations it's not very easy to achieve. The engine parameters need to be constantly and precisely adjusted according to various conditions such as speed, load, engine temperature, gasoline quality, ambient air temperature, road conditions, etc. That's why today's cars have much more electronics than in early days - there is a large number of various sensors and other electronic devices that help the vehicle computer or ECM to precisely control the engine and transmission operation and monitor emissions.
The vehicle computer system has self-testing capability. When the computer senses that there is a problem with some of the components it stores the correspondent trouble code(s) in its memory and lights up the "Check Engine" or "Service Engine Soon" light to tell you that there is a problem and your car needs to be looked at. To properly diagnose what is wrong, you need to take your car to a mechanic or a dealer. The technician at the dealership or a garage will then hook up the scanner to the car computer and retrieve the stored trouble code(s). Then he (she) will look it up in the service manual provided by a car manufacturer. The service manual contains the list of possible codes (about few hundreds) and describes what each code means and what needs to be tested. The code itself doesn't tell exactly what component is defective - it only indicates where to look, what engine parameter is out of normal range. The technician will have to perform further testing to pinpoint a defective part. and u can drive the car.

Why my Check Engine/Service/Check Engines Soon light comes on?
The engine computer or PCM/ECM
All modern vehicles have a computer or the ECM (Electronic Control Module) that controls the operation of the vehicle powertrain (the engine and transmission). The main purpose of this is to keep the engine running at top efficiency with the lowest possible emissions. With constantly growing demands for better fuel economy and new strictest emission regulations it's not very easy to achieve. The engine parameters need to be constantly and precisely adjusted according to various conditions such as speed, load, engine temperature, gasoline quality, ambient air temperature, road conditions, etc. That's why today's cars have much more electronics than in early days - there is a large number of various sensors and other electronic devices that help the vehicle computer or ECM to precisely control the engine and transmission operation and monitor emissions.
The vehicle computer system has self-testing capability. When the computer senses that there is a problem with some of the components it stores the correspondent trouble code(s) in its memory and lights up the "Check Engine" or "Service Engine Soon" light to tell you that there is a problem and your car needs to be looked at. To properly diagnose what is wrong, you need to take your car to a mechanic or a dealer. The technician at the dealership or a garage will then hook up the scanner to the car computer and retrieve the stored trouble code(s). Then he (she) will look it up in the service manual provided by a car manufacturer. The service manual contains the list of possible codes (about few hundreds) and describes what each code means and what needs to be tested. The code itself doesn't tell exactly what component is defective - it only indicates where to look, what engine parameter is out of normal range. The technician will have to perform further testing to pinpoint a defective part.

hi first i would get a mechanic to look at it and he will probably tell you its got to do with your brake pedal switch or you vehicle speed sensor

GMC S10/S15/Sonoma Pick-Ups 1982-1993 Repair Manual
VACUUM DIAGRAMS (See Figures 1 through 85)

Below is a listing of vacuum diagrams for most of the engine and emissions package combinations covered by this manual. Because vacuum circuits will vary based on various engine and vehicle options, always refer first to the vehicle emission control information label, if present. Should the label be missing, or should vehicle be equipped with a different engine from the car's original equipment, refer to the diagrams below for the same or similar configuration.
Check the link autozone.com (free register), select the year ('91 sample), Brand, Model, Sub-Model, Engine Size and make the next root...
1991 GMC TRUCK S15 4WD 4.3L TBI 6CYL REPAIR GUIDE >> EMISSION CONTROLS >> VACUUM DIAGRAMS

I really hope helps with this (remember rated this help). Good luck.

Your vehicle is sensing some sort of non-engine fault. In most cases, I have found it to be a burned up light bulb.