When starting to diagnose Nissan engine light codes, start by having a 10-mega ohm impedance capacity digital voltmeter to ensure proper measurements of sensitive engine electronic parts. But before proceeding with retrieving the codes, a visual engine inspection should be performed to check suspected wires related to the vehicle symptoms for chaffing, pinching, stretching or poor insulation. Also check for engine vacuum leaks visually on vacuum hoses and gaskets. Once these basic inspections are completed, we can proceed to retrieve the codes.

As in any vehicle made after 1996, Nissan check engine light codes can be easily retrieve by using an OBD2 scanner. You can connect this under your engine dash on top of your brake pedal. Once you got it, jot it down and get the code number. If you combine this Nissan check engine code with the vehicle symptoms, you can narrow down the possible culprit sensor or components causing the problem. Example, poor acceleration is related to tps sensor but no start symptom is not related to tps sensor…it more a related to crank sensor which can cause no spark (there must be a relation between the symptom and the affected sensor).

Once you have the engine fault code number and symptoms combined, here are some repair strategies to use:

If you have more than one code, fix the first code first
Once a code is being repaired, reset the code to confirm the fix.
If you have multiple codes followed by “no communication code”, most likely its a wiring or a computer problem

Fixing Nissan engine light codes require having a list of code description so you can understand the sensor circuit and analyze the problem. Sometimes, this list is built-in inside the scanner but you can also get it using a Nissan repair manual. From this description, you will see a “diagnostic tree” diagram on how to systematically check the components circuits and parts. Remember to use the wiring diagram when probing the wires and suspected sensors.

TIP:

ATS uses 2 methods that quickly give you the fix instead of using long hours of testing.

There are 2 general types of engine misfiring: random misfire and a specific cylinder misfire. On the first case, it is shown by a P0300 fault code whereas the cylinder misfire is designated by a code number like P0301, P0302, P0303, P0304,etc where the last digit denotes the specific cylinder where misfiring occurred. So if you have a misfiring fault code like P0303, it means the misfiring happened in cylinder number 3.

Diagnosing random misfire code:

This fault code is usually cause by a problem common to the engine: vacuum leak which can cause a lean fuel mixture, bad or defective fuel pump will also cause lean mixture including a defective or weak ignition like poor spark or low combustion due to worn cylinder, bad shorted wirings and defective sensor can also cause random misfiring. The trick in fixing this random fault code is finding the common culprit causing the misfire.

Here below are few examples:

Vacuum leak:

Check for vacuum leak: listen for hissing sound on vacuum hoses, spray mist of water on suspected vacuum leak at idle and rpm should change, do the same spray on suspected intake manifold gasket, a cracked vacuum hose can also do this misfiring for you. Out of time timing belt can reduce vacuum reading and cause random misfire.

Weak ignition:

Check the quality of the spark by checking the spark color and strength, check also if the spark is continuous. Weak ignition can be traced to defective ignition coil, spark plugs and wires and sometimes even a defective crank sensor and ignition module.

Poor fuel supply:

Measure fuel pressure reading using a fuel pressure gage and compare them to the standard specs. Clogged dirty fuel filter can also cause restricted fuel supply causing misfiring.

Shorted wiring or defective sensor:

When a wiring happens to be shorted, it can disturb the sensor signal to the computer and this can be verified by doing simple wiggling of the wires and it could reveal the culprit wire or circuit. Poor ground connection can also make electronic parts useless. On some sensor like the load sensors namely the tps or mass sensor, any defect on them can trigger random misfire under load.

Diagnosing cylinder misfire code:

This misfiring is best tested by checking the cylinder mechanical condition by testing the integrity of compression, fuel injector, spark on the specific cylinder and compare it with the cylinder that is working. One popular technique used by some mechanics is to switch the defective spark plug or ignition coil or coil plug to a good one and see if the code will also move. Example, if after you switch the cylinder #1 coil plug to cylinder#4 and after testing the fault code changed from P0301 to P0304, you know that the coil plug is the defective. This switching can also be done on suspected injectors, plug wires, ignition coil, etc. as long as the cylinder causing the misfire is identified.

Tip:

On some engine code scanners, a freeze frame data can be seen live on the exact condition of the engine. This can save you time in analyzing the defect of the cylinder.

The feared Honda check engine light is familiar to everyone: you are driving your vehicle one day and suddenly, the “check engine light” indicator shows up in your dash. What do you do? Do you bring it to the garage right away? In essence, when the Honda check engine light is on, it definitely warns you that a fault in the electronic circuit is detected. As a matter of fact, everytime any part or sensor of your engine fails, it is recorded in the computer memory. Your job is to get these codes and learn how to fix them to avoid wasting your time and money.

Here are a few things to remember about Honda check engine light:

1.) First of all identify what kind of troubleshooting system your vehicle has. Example, any Honda vehicle made before 1993 uses OBD1 where the fault codes are retrieve using a jumper wire or counting light flashes in the dash panel. Any vehicle made after 1995 strictly uses OBD2 system where you will need an engine scanner to retrieve the fault codes. This scanner is readily available and can be bought cheap instead of going to a garage that will charge you $60-$80 to scan your code once. Once you have the scanner, you can always scan it any time you see the check engine light.

2.) Assuming you are pressed for time and wants to fix the fault code yourself, get hold of a Honda fault code list/service manual and it will tell you how to check the individual sensor or circuit. For OBD1 system, here is a quick reference you can use:

http://www.extreme-check-engine-light-codes.com/HONDA_OBD1_Decoder.htm

Let say for example you have an EGR sensor fault code, just go and read everything about the sensor description, wiring and servicing and you should be on your way on fixing it. When dealing with numerous code, always fix the first one first before going to the 2nd fault code and so on. At the same time, always reset the code after each code repair is completed.

3.) To reset the fault code on pre 1993 vehicles, disconnect the battery connection for about one minute and reconnect. For newer vehicles made after 1995, the back up or ecm fuse can be removed for 10 seconds and reconnected instead. This should be located in the engine fuse panel.

Powerful Troubleshooting Honda engine light codes Tools:

1.) On pre 1993 Honda engines (OBD1), use the troubleshooting chart for testing the defective sensor or circuit which can lead you to the fix. This is available in OBD1 Honda manuals.

2.) Once a fault code is known, you can also use the search engine and any online resources to find the solution of the code like forums.

3.) On post 1995 Honda engines, you can use the wiring diagram to test the sensor or ecm (computer) wirings so you can verify and test the fault OBD2 codes. Using a digital voltmeter and few handy tools is more than enough to do the repairs. The important factor here is having the wiring diagram to help you locate the circuit and faulty wires, sensors or engine components.

Troubleshooting tips on wiring diagram:

The wiring diagram can leap frog your technical skill because of the following advantages:

1.) Identification of each sensors using their wiring colors and exact location. Using a digital voltmeter, you can access the location of the sensor plug in and voltage test the wires there to find if the sensor is shorted (wires with bare or damaged insulation) or if the sensor is open (cut or damaged wire).2.) Measuring also the resistance reading of the sensor, you can determine if the sensor is defective internally. 3.) Finally, by measuring the ecm (computer) wiring terminals for voltage, you can simply measure the power, ground and reference voltage to find out if the ecm is OK or not. And remember…all of these can be done by you by just having a scanner and wiring diagram.

NOTES:

See the pictures above showing:

How to test the engine sensors using the wiring diagram and a digital tester.
How to back probe your ecm (computer) terminals pins to verify the integrity of your ecm (you can also watch these in a VIDEO if you are an ATS member).

4.) To make the fault code analysis quicker for you, you can get a list of common fixes for the fault code and get the assistance of an online mechanic. This option is a lot cheaper than paying a garage $100 per hour to fix it for you. Besides, this will speed up your learning curve and avoid mistakes which you might do while starting up to do your own repairs.

Finally, to fix and troubleshoot a Honda check engine light, you can use this proven strategy when faced with a Honda fault code problem.

Thanks!

Troubleshooting the check engine light for 2002 Toyota Tundra by any do it yourselfer should be easy if you use an OBD2 scanner. Just remember to specify that the scanner you have will work for this vehicle. In some generic scanner, the Toyota codes will not work because the scanner is only good for domestic vehicles like GM, Dodge and Ford.

Diagnostic Troubleshooting Specs:

Diagnostic connector is located on the right of the steering column just below the dash. A scanner can be hooked up to the diagnostic connector to retrieve the fault code.

Diagnostic fault codes are stored using 2-trip detection system whereby the fault code will not show up the first time it is detected but shows on the 2nd time the code shows up. This usually applies to generic scanner but not on Toyota scanner.

Fault code that are scanned can be seen using a “Freeze Frame Data”. This system will show the actual condition of the engine when the fault code appears. This conditions includes engine temp, engine speed, vehicle speed and other factors leading to the code. However, if there are multiple codes store in the memory, only the first code will show in the freeze frame data.

Diagnostic TIPS:

The most common obd2 problem on this 2002 Toyota Tundra are the oxygen sensors. This applies to the upstream sensors located in the exhaust manifold and the downstream oxygen sensors located after the catalytic converters. If your vehicle has mileage under 100k, try contacting your Toyota dealer because sometimes, those sensors are covered by warranty. In case you need to fix it yourself:

1.) Measure the oxygen sensor signal voltage as soon as the engine warms up. It should fluctuate between 0.1v to 0.9v or around 0.4v to 0.6v difference. The rear CAT sensors difference is much closer which is around 0.1v to 0.3v. Any sensors out of these ranges should be replaced.

2.) If the oxygen sensors are covered in the warranty, sometimes the exhaust manifolds are covered too especially if the manifolds are leaking which can cause the upstream sensors to fail again if not replaced. Ask this coverage when dealing with Toyota dealers since this job is very expensive if you fix it yourself.

Thanks!

From 1995 onwards, the Audi car manufacturer has been using immobiliser system. This system consists of an immobiliser ECU that controls the signal for ignition key and the engine electronic control system. Since not all diagnostic trouble code reader is showing in the light and using a scan tool is the best way to show the code because it is handy. Also, this new system can erase the trouble codes and reset it after the trouble code is repaired.

This new VW Audi code reader is a portable scan tool which can be hand help using your palm. It uses a diagnostic protocol called ISO 9141-2 and ISO 14230-4. This code reader is designed especially for diy or do it yourselfer and even regular professional mechanics. This tool can identify and help you fix Audi troubleshooting problems including most Volkswagen vehicles from 1996 up to the present. as long as your Audi vehicle has a 16-pin “OBD” 2 style” data link connector on the left side of your steering column, this new Audi code reader will work.

Be warned though that when using the Audi code reader, it will easily find the trouble code by reading it directly from the Audi code reader. It allows it to identify, locate, read, erase and reset the code that is stored in the code reader code memory. So instead of paying a mechanic to do it for you, use this OBD2 code reader to do it for you. This is a powerful device that can also scan ABS and airbag codes besides your power train engine codes. And when you buy it and can be easily stored in your glove compartment.

Air bags are called supplemental restraints because they are designed to work best in combination with safety belts to protect the occupants of a vehicle. According to the US government, starting 1998, all passenger vehicles need to have front air bags and safety belts. Also, this government regulations applies to light trucks on the following year.

Tip on air bag light:

The air bag light is on because there is a fault in the safety restraint system. When this happens, have someone scan the safety restraint control module for codes. Also, when the Air Bag light stays on, it means that there is an electrical problem with your Air Bag system. The first thing to do is to make sure that the air bag fuse is not blown.

When Air bags system is working, it allows electrical contact inside the airbag computer module . From there, the wiring from the horn and cruise control are connected through the clock spring (located in the steering wheel) which also connects to the airbag through a common ground. When a collision occurs, the airbag module activates the air bag deviced called inflator which acts as a trigger. Inside the air bag assembly, it contains pellets of sodium azide which when ignited produces nitrogen gas. This latter causes the airbag sudden expansion during collision protecting occupants at the front of the vehicle.

Tip on air bag operation:

When Air bags are activated, it will inflate instantly during impact of a collision making sure the driver and front-seat passengers from being thrown against the windshield. To make it really work however, it should be supplemented with a seat belt.

Until passenger vehicles and light trucks are equipped with smart air bags which are shown to be safe and effective, all children aged less than 12 years should ride in the back seat using age and size appropriate occupant restraints. Air bags is mainly constructed for frontal impact collisions which is responsible for more than half of all car collision deaths. Airbags are designed to minimize head and chest injuries by distributing crash forces equally across the body of the affected occupant.

Trying to understand OBD2 diagnostics, the information available through OBD has varied widely since the introduction in the early 1980’s of OBD computers, which made OBD1 possible. When OBD was first applied, it would show a check engine light or CEL, if a problem were detected. The problem is, it would not show any solution as to the exact nature of the problem which makes OBD1 difficult to use. On the other hand, the OBD2 standard specifies the electrical signaling protocols available, and the messaging format thus leading you to the suspected circuit. It also provides a candidate list of vehicle parameters to monitor along with how to interpret those parameters. All of these is given on the instruction manual that comes with the code reader.

With the introduction of OBD2, it is quick and easy to understand the cause of a vehicle’s Check Engine light (DTC) problem because it will display generic and manufacturer-specific diagnostic trouble codes along with their detailed descriptions. Some OBD2 software also provides access to Freeze Frame data which records the status of vehicle sensors at the exact point in time that the Check Engine light was triggered. The Check Engine Light (CEL) will illuminate anytime a vehicle’s emissions exceed 1.5 times the federal test procedure standards for that model year of vehicle. Some codes require the faulty condition to occur twice before the MIL comes on. This is performed since any defect in any of these systems could cause vehicle emissions to surpass the allowed level. The electronic components being monitored can include such sensors dealing with engine rpm, throttle linkage position, engine coolant temperature setting, crankshaft angle, engine knocking, fuel chemical breakdown and others.

Like the OBD1 that was used before, OBDII is a new government regulation mandated to lower car emissions. However, what makes OBDII to stand out is its user friendly application that is adaptable for all newer vehicles like car and trucks that cover most imported and domestic vehicles.

When your Jeep engine light comes on, it means that the engine management computer has detected a problem related to emissions or engine operation. Normally, this also means that something needs to be repaired to comply with federal emissions requirements. Using a Jeep OBD II scanner, it can easily retrieves the fault codes and its definitions from Jeep’s memory to point you to the problem circuit or sensor. To prevent frequent engine fault code coming out on Jeep engines, regular engine maintenance and repair should be done on your Jeep vehicle. Using a Jeep service manual, use it as a guide before fixing any Jeep engine light codes.

When you scan the Jeep engine light codes, sometimes the Jeep computer need to be reprogrammed and most of the time, the dealer is the only one that can do proper troubleshooting because of the fact that the equipment used on most small garages do not own the proper Jeep diagnostic tools. Most Jeep engine sensors are directly inputted to the computer management data collection and determine the correct fuel and air mixture. If these Jeep sensors become defective, then the computer is being fed faulty information which can corrupt the gas mileage output. It is then imperative that when faced with a difficult Jeep engine light codes that you contact Jeep dealership right away.

Sometimes, the Jeep engine computer uses an electronic chip which is connected into your engine computer to increase horsepower and torque boost. Getting more road power, this “miracle” chip is the quickest way to get it. This Jeep chip can provide all kinds of power from the fuel to give you better mileage and more power at WOT. This chip is also available from your Jeep dealer when you see them about your Jeep engine light codes.

The OBD2 Code readers are usually sold to automobile diy’s and non-professionals who are curious about what codes that some vehicle diagnostic systems have stored in their engine computer memories. A common obd2 ode reader that is selling for under $200 is INNOVA 1003 obd2 code reader. This code reader not only scans your fault codes in your vehicle, it also allows you to view freeze-frame live data and pinpoint the suspected defective circuit. Instead of having to recreate a scenario over and over again, the data can be played back to scrutinize all the resulting information and make a clear guidelines in troubleshooting the problem. The INNOVA 1003 obd2 code reader can monitor and also record the engine rpm, coolant temperature and other trouble codes stored in the engine computer memory. Another feature of this code reader is its ability to supports EOBD or the European version of OBD2 decoder beginning 2000 engine models.

Furthermore, the INNOVA obd2 code reader has more complete data displayed on its user friendly monitor which is convenient for the user. The LED display is provided by showing a look-up table to provide the user a trouble code description which is very handy. Having been patented as a all-in-one function, it display 19 pieces of computer management data that includes diagnostic fault codes, pending codes, evaporative emissions figures and other information.

This INNOVA 1003 obd2 code reader has also unique function to retrieve and reset OBD codes from engine computer. It has a user friendly lcd monitor where the codes and their description are shown. INNOVA 1003 obd2 code reader, being a stand alone unit, can be kept in the car all the time ready like your glove box for use to check and clear codes if the CEL (check engine light) comes on at any time. This makes it handy in case your vehicle will have any malfunction while it is on the road. If you intend to buy your own OBD2 code reader, maybe this INNOVA 1003 obd2 code reader is the right tool for you.