A common way in checking your vehicle’s modern abs code light is by verifying the wheel speed sensors. These wheel speed sensors are usually located at the back of the brake rotor on vehicles using 4 wheel disc brakes. In contrast, other cars or trucks with rear-drum applications, the wheel speed sensors are anchored in the differential banjo housing or at the back of the drum housings. Regardless where the wheel sensors are mounted, these brake sensors are designed to record brake information about the wheel rpm in the brake computer memory. As soon as the brake pedal is pressed, it will activate the abs when the wheel speeds are not the same and if there is an indication of a wheel lockup, the abs computer will command the anti-lock mechanical system to adjust to make the wheel speeds the same for all 4 wheels.

Assuming your ABS light code is having difficulty to go out, and you need to try turn your ignition key several times and if the light does not go out, then it is time to check the abs circuits. The ABS light can be restored by turning the key on (engine not running) and depressing the gas pedal to the floor three times and the computer will reset the abs light code. On some vehicle models, the abs is bypassed by a jumper wire and the abs light code warning light will flash in sequence displaying the trouble codes. Normally, the common breakdown of the abs system is the hydraulic gas charged accumulator failure which cycles the turning on and off of various switches when the pressure pump overruns. For specific abs diagnosis of a particular vehicle, please contact ATS.

As soon as there is a failure or a downgrading of the engine performance, obd2 code reader triggers an engine light flashing in your dash which indicates a fault code. Even unrelated circuits such as transmission system, abs or even the evaporative system could be triggered also. This is especially true if the above system are connected by a common ground or power supply wirings. To avoid the confusion during troubleshooting, make sure to start the check ups and testing on the fault code that first appear in the obd2 code reader. And when a minor code appears during testing, it is advisable to reset it first before treating it as a serious problem. However, if the minor code persist on coming back, it is an indication of a possible serious engine problem such as wiring, an engine sensor or computer fault.

When retrieving obd2 code problems, some code reader can be used to give the exact fault code numbers which can be verified using a list of description referring to the fault code number shown. This list can come with the code reader or the reader can show it directly built-in on the code reader. This is pointed out because there are many code readers that do not have this feature which makes troubleshooting difficult for the user.

Besides supplying the fault code, it can have the feature to tell the user if the vehicle is smog free. This feature is important if your vehicle needs smog certification when the vehicle needs it during vehicle registration. Finally when buying your own obd2 code reader, make sure the fault code list description is included and to insure quality, it should have ISO protocol capability hardware which could be a stand alone or separate hardware.

All vehicles sold after 1996 were required to have a diagnostic system programmed in the obd2 code reader that let emission inspectors and service professionals track emissions related vehicle problems. Included in the system is a set of live records that has to be monitored when performing troubleshooting. This is possible because it allows the code reader to tap into the computer’s memory and analyze them in a quick manner. Fault codes will be generated as soon as any programmed part circuit/component goes beyond its assigned range. Example is an oxygen sensor that has sensed an overly rich or lean fuel mixture, a code will be generated in the computer memory.

When a code is flashed in the vehicle dash and retrieved by the code reader, it tells the user which circuit is affected. However, it does not tell you exactly how to fix it meaning as soon as the defective circuit is revealed, the user is expected to check and fix the suspected circuit/engine component. The advantage of the OBD2 code reader from its predecessor is its uniformity of its connections and standadization of the fault code names which was very confusing in the old OBD1 system. All the new changes in the OBD2 systems was also approved and mandated by the government’s Environmental Protection Agency.

When the obd2 code reader is plugged into the vehicle, it allows the serial data downloaded for quick analysis of the fault codes. On some models, a self test is incorporated to verify the integrity of the code reader and the engine components being tested. Resetting the engine computer can be done quickly by the obd2 code reader which is preferable than disconnecting the battery which can cause interruptions in the vehicle accessory circuits.

If you own a vehicle with models 1996 and up, OBD2 code reader is a tool that can help you perform troubleshooting repairs and diagnostics. It can retrieve trouble codes direct from your engine computer located in its memory. Since 1996, the government imposed a regulation requiring all obd diagnostic tool have a common feature for all types of vehicles. This is a departure from OBD1 where every car manufacturer has its own unique diagnostic tool which is expensive for garages trying to fix them. The newer system has the scanner to display the trouble codes which are accessible from the same location for all vehicles.

Aside from displaying the trouble codes on the new OBD2 scanner, it also gives a description of the meaning of the code pertaining to the affected circuit. On some models, the code reader has the ability to erase the fault code including live data showing the actual functions of the circuit components while the vehicle is being ran. Furthermore, other functions are also available on some obd2 code reader like programming of the engine electrical sensors, solenoids and computer module and recoding of ignition key. These features displayed in live graphs are really important when analyzing the engine problem. Be warned though that the code reader only give you the possible area or circuit of the problem but not the exact cause of it.

When buying your own code reader, make sure to check the obd code reader seller that the the diagnostic tool will work for your vehicle. Some obd2 code reader will work only on domestic but not on imports and vice versa that is why it is important to clarify this fact before buying the diagnostic tool. As soon as the trouble code is fixed, the code reader should allow the user to clear and reset the code.

When this P0205 starts flashing in your dash, it means the injector cylinder #5 circuit malfunction. As you will know, each injector has 2 terminals; namely the power source and the ground supply. The power source can come from a fuse, relay while the ground supply is almost always supplied by the engine computer (ecm). When any of these 2 wires are shorted or open, this P0205 code will come. Besides from the mil light coming on, other symptoms could be misfiring, cutting off and hesitation.

The first thing to do when checking this P0205 code is to check the wiring harness leading to the injector circuits. This is important specially if the harness wires are exposed to heat, oil and bad routing. On some Asian models, this problem is so common that the injector wires are replaced regularly by the dealer whenever this code appear. On the other hand, domestic engines will cause this code when there is failure in the tps sensor. This is evident if the symptom is accompanied by hesitation and could be tested by wiggling the tps wires during idle and the bad symptom will re-appear. When confirmed, this problem is fixed by replacing the tps sensor.

If after doing all of these recommended repairs and the fault code re-appears, it is possible that the ecm itself is at fault. This can be checked by testing the ecm terminal pins for battery and ground supply. When performing all these tests, it is assumed also that the injectors are tested for correct resistance and basic tune up check ups done.

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This P0351 code stands for ignition problem in the primary circuit which can cause a misfire accompanied by the flashing of the mil (malfunction indicator in the dash) light. This ICM is used by your engine computer to gather the speed signal in calculating the timing of the spark. If that signal is interrupted or out of range, a code will be set up by the ecm. When dealing with ignition control module, we are talking about 2 basic ignition system such as the one with distributor and without distributor. On the distributor system, the speed signal comes from the rotating distributor shaft monitored by the pick up coil. On system without distributor, the speed signal is gathered by the crank sensor which monitors the crankshaft rotation.

The primary circuit of the ignition coil operates on battery voltage whereas as the secondary circuit the carries the high voltage such as the one that fires your cylinder. The primary circuit includes the crank sensor or equivalent pick up coil, part of the distributor and all circuits that collects the speed signal for the engine computer. In severe cases, if the ignition module completely fails, it can cause no spark. To test, check the ICM for power supply and do the same for ignition coil. Using a test light, probe the negative terminal of the ignition coil while cranking. It should blink while the engine is being crank. If the engine has no distributor, replacing the crank sensor should fix this code.

There are many types of ignition system being used in different engines and to be able to fix this code, one has to get the symptoms of the ignition problem so we can identify the fix. Example: an ignition control module failure means replacing the distributor on one type of engine but it could be a defective crank sensor on the engine without the distributor. Also, with the correct engine designation, the correct ignition wiring could be used to troubleshoot the ignition problem.

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Having an Acura vehicle with P0336 code points to a defective crank sensor. This code will show up everytime the crank sensor sends a defective speed signal to the engine computer (ecm). The symptoms for this P0336 code are long cranks and hard starts accompanied by the mill light in the dash. The engine could also show signs of misfiring and surging. If this code appears, reset the code first and see if the code re-appears. If it does, check the crank sensor wires, sensor resistance and replace the crank sensor if necessary if found out of range.

When testing Acura crank sensor wires, concentrate on the connections located at the front pulley which might be rubbing a metal causing the short. Follow this connection until you are convinced the wires are safely routed and insulated. If in doubt, you can peel the wiring harness to get a closer look. If after correcting this and replacing the sensor and the code still is coming back, trace the wiring connections of the sensor up to the ecm pins. Check the wires for continuity, corrosion in the plug-ins and tightness. Otherwise, check for mechanical cause such as a jumped tooth in the front timing gear which can require a timing belt replacement. Sometimes, after the timing belt is replaced, this P0336 code comes up which shows that the crank sensor wires were pinched during the timing belt replacement.

TIPS:

This code repair above assumes you have done basic repairs such as replacing the spark plugs, clean EGR system including throttle body with brake spray cleaner, etc.

Sometimes, after replacing the crank sensor, you might change the cam sensor too. Contact ATS for more details.

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When you see this P0500 code on any BMW vehicles, this shows the speed sensor has a malfunction. However, the description of the code is a misnomer because when you say speed sensor, it refers to the speed sensor located in the transmission. On this code, the actual sensor being referred to is located on the brake wheel speed sensor located at the rear of the vehicles. This is the common mistake because if you change the speed sensor at the trany, then you just replaced the wrong part.

The rear brake wheel sensor monitors the rotation of the rear wheel to help in controlling your ABS. A lot of times, the sensor has the probe covered with dirt or mud which can cause erroneous signal voltage readings. The same situation of the sensor wirings are damaged. To check the integrity of this rear wheel brake sensor, disconnect it from the reluctor ( a counter with splines or teeth to measure the brake wheel rotation). Then measure the resistance across the sensor which must be around 1000 ohms. Also measure the sensor ac voltage but do it with the sensor connected and wheel raised while being spun.

Next time you see this P0500 code on BMW, remember to disregard the trany sensor located in the transmission but go straight to the rear wheel brake sensor. To make sure you got it right, perform the test on both rear wheels if each rear wheel has its own sensor otherwise one test is enough if there is only one rear wheel brake wheel sensor.

Tip:

If after testing and replacing the rear wheel brake sensor and the P0500 code remains, consider doing a test on the traction control module if such components is available in the vehicle. You will see this if you have a complete wiring diagram of the ABS system and trany wiring circuits. If you need the wiring diagram and online assistance to this , please contact ATS.

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P0507 code refers to high idle disorder which cause your engine rpm to surge and setting this code in your dash panel. When troubleshooting code like this, the best route in fixing this is to check for vacuum leak first. High vacuum leak means more air is coming than fuel in the engine mixture. To compensate, the engine computer will command to inject more fuel causing the high idle and this P0507 code. The common symptoms besides surging are poor gas mileage, hesitation, cutting off and hard long starts after the engine warmed up.

Testing your vacuum leak should be your top priority which you can easily do using either a propane or water bottle sprayed on suspected area like throttle body gasket, intake manifold and egr valve. If this spraying is done at high idle, the rpm should go down as soon as the vacuum leak is sprayed. One great technique used by a lot garages involves removing the dipstick from the dipstick tube and installing a vacuum gage. Also, the pcv valve is removed and pcv hole plugged in the valve cover. With engine running on idle, there must be no vacuum leak. If there is a leak, the engine has an intake manifold gasket leak.

Beware that this P0507 code can be caused by uncontrolled fuel supply. Examples are if the fuel injectors are plugged and defective, this can cause havoc in your fuel mixture. This can be checked by unplugging the injectors one at a time and observe a drop of rpm. When there is no rpm drop, that fuel injector last removed is the culprit. Another method is to check the vacuum hose for the fuel regulator. If remove, the engine rpm should go up otherwise, the fuel regulator itself is a suspect. This can be verified by checking the fuel regulator diaphram for signs of rupture or smell of gas leak.

Therefore, the 2 main issues that could cause this code is an vacuum leak which will cause the computer to compensate or too much uncontrolled fuel which also has the same effect: rich fuel mixture.

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A GM P1635 code means 5 volt reference 1 circuit malfunction. If you remember, most GM engine computer (ecm) sends a 5 volt reference to all sensors when monitoring the engine electronic system. Example is the 5 volt reference 3rd wire you will find on the tps sensor and map sensor along with the ground and signal wires. If this 5 volt reference change in value other than 5 volts, a P1635 will be flagged by the ecm. Some of the symptoms when this code appears are erratic idle speed or occasional engine going into high idle without stepping on the gas pedal.

The most common way to check this GM P1635 code is to measure and verify the 5 volt reference wire at your tps, coolant sensor, egr valve and if possible disconnect each of them one at a time. Hooking it up to a DVOM, the 5 volt reference reading can be monitored every time the sensors are unplugged. It is also suggested to check the ecm by disconnecting the ecm terminals making sure that the ecm pins are clean and not corroded. On extreme cases where the 5 volt reference is difficult to diagnose, the ecm pins are checked for ground and supply voltage and if proven OK, will result in replacing the ecm. Do this only if you have a wiring diagram and has the assistance of an experience online mechanic.

Tips:

When checking the ground voltage terminals on the ecm pin terminals, put the vehicle under load like your head lights to force the defective faulty ground wire to come out.

On advance set up, a good scanner can be hooked and then monitor all sensors connected to the 5 volt reference wire. With the vehicle road tested, all 5 volt reference voltage readings can be compared for changes and figure out which sensors or output loads are affected. This service should be available from any small garage if you have difficulty in finding the source of P1635 code.

If the ground voltage exceeds 0.250 volt, a practical tests can be done by checking your battery connections and all ground supplies to the engine, ecm, sensors and output loads. For a detailed assistance on this, please contact ATS.

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