Code 71, egr system malfunction and then i do a few things to check my system, 1 checked the egr valve and did the vacuum test and the engine stalled like it should. The egr pressure feedback sensor, also known as the delta pressure feedback sensor, is a sensor that detects the pressure changes in the egr system. The exhaust gas recirculation egr system is used to reduce nitrogen oxide emissions. By controlling the flow of exhaust gases into the combustion chamber it can reduce production of nox by lowering the oxygen concentration and peak combustion chamber. Use manufacturers data to identify the switched earth circuit for the egr vacuum solenoid valve. If the egr valve opens and the vacuum holds for more than a minute, the egr valve works. The egr valve also includes a lift sensor, a similar device to a throttle potentiometer. Egr bypass trick to boost mode for 60 series 14 liter 2006.
Jun 12, 2010 details the testing procedure for the egr position sensor. Egr lift sensor what informs your honda civic ecu of the real time position of your egr valve. The exhaust gas recirculation egr valve is one of the earliest forms of emission control for internal combustion engines, but it does more than just help you ride cleaner. And lower combustion temperatures mean lower emission of harmful nox oxides of nitrogen gases. Often, an egr valve might work while testing, but stick intermittently. It works together with the egr solenoid to control the. I continued to watch it as i noticed it continued to go down a tenth every 2 seconds or so. Egr valve position sensors crankshaft position sensors. Testing egr systems exhaust gas recirculation pt 2 news. Innova 3040 diagnostic scan toolcode reader with live data for. The egr valve and map sensor are quite accessible on this particular engine so testing the system was straightforward.
It works more like a potentiometer and has a reference voltage. The procedure to test an electronic egr is a bit different and requires a multimeter. Still working to find some sort of alternative to the temp sensor at the intake and when i figure that out, i will post up the completed temp sensor testing harness. The engine starts fine but then it starts surging between 800rpm and honestly sounds like it is trying to stall. Note that this test lacks the rpm compensation of the idle air control iac valve.
The egr system is made up of several components that work together to accomplish this task. The sensor collects vital information and based on this information, the egr valve determines when to open and close. Carsntoys is a member of the amazon influencer program. Egr works by recirculating a portion of the engines exhaust gas back to. The job of the egr is to allow a percentage of exhaust gas directly from the engine to pass through the egr cooler and in to the intake system. By helping the engine run at lower temperatures, it increases engine efficiency, providing a larger throttle position and reducing pumping loss.
Testing an egr solenoid valve pico technology pico auto. The egr monitor is a small program that runs inside the ecms memory. The egr valve and map sensor are quite accessible on this particular. The sensor monitors and measures the pressure with the egr valve. Easy to install and im guessing its working since no check engine lights. This sensor is in charge of detecting the position of the egr valve. Egr system testing automotive diagnostics and publishing. With the sensor removed from the egr and still connected, press the plunger and watch the voltage change on the brownlt green wire. About a week and a half goes by and the cel pops back on. The quality of our products are guaranteed by advanced work equipments and the test equipments are designed,implemented and.
Testing egr valve mercedes mbe 900 diesel engine mechanics hub. Problems in other systems may cause this same symptom as well. Egr and egr bypass valve problems chevy and gmc duramax. Ecm senses less oxygen therefore less fuel to make the mixture for optimal combustion correct. When the egr temperature sensor fails, it causes various issues with the egr system and the situation should be addressed quickly. The egr system in your vehicle uses the egr valve to introduce measured amounts of exhaust gases back into the combustion chambers. Driveability corner egr system maf map motor magazine. It is the job of various sensors and actuators to make sure that the egr system. If you notice your vehicle running poorly, stalling or having poor gas mileage, you should test the egr. Use the blackwhite wire for the ground for the dvm.
Jan 26, 2019 learning how to test an egr valve will save you time, money and some headaches. Function testing egr valve help i have been experiencing problems with my 2003 tdi golf 124k miles at startup whenever the engine is cool. The testing procedures shown in this video apply to all electronic style egr systems. At the 30second point, i commanded the egr valve to about 66% open. How to test the ford egr valve egr vacuum solenoid, dpfe sensor. A preset springoperated regulated valve mounted in the highpressure fuel pump is used to maintain internal fuel supply pressure. Sinister diesel new egr valve for 20032004 ford powerstroke 6. Egr to manifold gasket, 3 small screws and gasket for the egr sensor goes on top. A manifold absolute pressure map sensor is fitted to the intake manifold. Egr position sensor egrp the threewire fixed potentiometer egrp sensor monitors the position of the egr valve. Egr code 71 1994 fzj80 cleaning temp sensor ih8mud forum. Wed recommend taking pictures of the engine bay and connections to and from the egr valve and if fitted the egr cooler before beginning work. The egr system is crucial for reducing carbon emissions.
This is the offset voltage, which can be monitored with a scan tool or voltmeter, and will ascertain whether the sensors calibration is skewed or not. To test operation of egr valve, apply and release vacuum to valve using a vacuum pump, or manually depress and release diaphragm. This egr valve is controlled through an egr temperature sensor. Average rating from 127,991 customers who received a exhaust and emission system inspection. One of these components commonly found on many egr systems is the egr pressure feedback sensor. Once the vacuum is released, the valve should close fully. The p040d code is pointing to the right side ergt sensor circuit being open or shorted.
The valve only operates after the engine temp gets above approx 50 degrees celsius, the van is in gear and moving. The ecm uses this signal to verify proper operation of the egr valve and motor for emis. The egr system works by recirculating exhaust gases back into the engine in order to lower cylinder temperatures and nox emissions. Egr valve testing the key steps professional motor. A defective component in the egr system may have a very detrimental effect to the engine performance and therefore the emissions. Similarly, an increase in nox may be caused by a vacuum leak, a clogged fuel. This is the offset voltage, which can be monitored with a scan tool or voltmeter, and will ascertain whether the sensor s calibration is skewed or not.
The vehicle computer operates the valve instead of previous years egr valves, which are operated by the engine vacuum. Obd ii may check for a drop in intake vacuum through the map sensor when it commands the egr valve to open. Test the exhaust gas recirculation egr valve by using a vacuum gauge or hand vacuum pump. How to test for egr flow problems gm electronic egr test. They have a update part and software for the engine computer. Mar 12, 2019 the function of the exhaust gas recirculation egr valve is to recirculate the engines emissions. How to test an electronic egr valve gm p1406 case study. So, a stuck open egr valve will create a lack of oxygen in the exhaust. Sensor issue the differential pressure feedback egr sensor can go faulty and cause the egr valve to stop operating properly and throw the code. If you need the egr valve test for the egr valve marked with the x, you can find it here.
Put a vacuum gauge between the disconnect vacuum line and the intake manifold port. Repair information is becoming scarce and inconsistent for all vehicles, but is even worse for these bosch fuel. If a vacuum diaphragm inside the egr valve is leaking, the vacuum will drop. Part 1 how to test the ford egr valve egr vacuum solenoid. The purpose of this test is to examine the control signal voltage at the exhaust gas recirculation egr vacuum solenoid valve during engine hot run conditions. Diagnostics, testing, removal and installation of egr valves should always be carried out by suitably qualified persons. Common symptoms of a bad egr valve you might not know. Diagnostics, testing, removal and installation of egr valves should always be. The sensor is used to tell the engine computer what the egr is doing. Its tucked under the egr valve and is held by a 14mm nut. Vehicle specific duralast egr valve pressure sensor su588. Disconnect a vacuum line connected to an intake manifold port.
The function of the exhaust gas recirculation egr valve is to recirculate the engines emissions. Common problems, symptoms, egr valve testing, bulletins, replacement. Comes with a gasket but the gasket that comes with the egr valve is better and looks like the original oem, so i used it instead. Details the testing procedure for the egr position sensor. Egr valve pressure sensor best replacement egr valve. Apr 20, 2018 the egr valve is basically an electric motor opening and closing a valve. Recirculation of the exhaust leads to a gradual accumulation of carbon particles inside the inlet. Oct 27, 2010 the car runs fine, but the code says the egr system has a problem. Usually if there is an egr valve code the pcm and goes into limp home mode and disables the cruise control, might want to try and see if the cruise is working. Oct 20, 2009 the egr valve in photo 3 of 4 with the red x is not covered by this article and is tested differently. I had noticed it was a bit sluggish but i just assumed thats the way it drives.
These devices are an effort to control the amount of exhaust gas recirculated by metering exactly how far open the valve is, and they work as variable resistors, just like a throttle position. So if you have a scan tool hook it up and lets go, if not read on and well get around that too. There are several ways to troubleshoot an exhaust gas recirculation system. The egr funnels cooled exhaust coming from the egr cooler into the intake system to cut down on emission levels. An egr tester, such as the new egr and solenoid valve tester from sp diagnostics, is able to drive the valve under manual control. I think messing with your baro sensor will also make your engine run with less than 100% efficiency. Common signs include engine ping or knock, the check engine light coming on, and failing an emissions test. Iirc this is only applicable to all 1994s and california 93s as nonca 93s didnt have a temp sensor someone correct me if im wrong. High volts could mean there is a blockage somewhere within the egr valve and no voltage could signal a problem with the valve and computer communication. That would also account for the idle problems better than a stuck closed but not stuck open egr valve. Strict emission laws and the malfunction indicator light generally illuminated when a system fault exists, require a prompt resolution.
Learn how to test an egr valve in a few minutes to confirm you actually. The egr system reduces the formation of oxides of nitrogen nox in the exhaust when the engine is under load. Vehicle specific duralast egr valve pressure sensor su14678. If the car doesnt stall, assuming the bench test was successful, theres. You can do it first as a bench test out of the car then on the car. Gmvauxhallopel have a similar system, but the solenoid valve, lift sensor and the egr valve are all one unit. Although this can be done with the valve insitu, it is of limited benefit due to the fact that the user is unable to see how the valve is behaving. Best rated in automotive replacement emission egr valves. Faultfinding is also made harder by the fact that egr takes places inside the cylinder head through a passage connecting the exhaust and inlet manifolds. Such a design without an egr valve has the drawback of always being in operation. Exhaust gas recirculation system repair guide autozone. This sensor detects temperature changes in the egr passage way.
Dec 09, 2015 the egr valve and map sensor are quite accessible on this particular engine so testing the system was straightforward. Symptoms of a bad or failing egr pressure feedback sensor. Furthermore, the ecm sometimes uses the oxygen o2 sensor to check for proper egr operation and sets a code if necessary. After reading the diagnostic fault codes, i used an actuator test on the egr valve. To find your honda civic ecu, you will need to open your passenger side door and remove the kick panel. Jul 06, 2017 this egr valve fault code popped up and it caused a slight hesitation on acceleration which would make sense if the valve is open at the wrong time.
An increase in hydrocarbon emissions isnt necessarily caused by a stuckopen egr valve. The egr valve in photo 4 of 4 with the green check mark is the one covered by this article. How to test egr solenoid vacuum valve geo metro forum. The code was 1896 egr valve controller out of calibration. Part 1 how to test the gm egr valve buick, chevy, olds, pontiac. This means that the people who created the engine management and emissions systems and the people who wrote the repair information didnt always understand each other. The last part of your honda civic egr system is the actual ecu or engine computer. The egr temperature sensor is an engine management sensor that is part of the egr system. The first thing to look at, when testing an exhaust back pressure sensor, is the sensor signal output voltage at idle egr closed. It works together with the egr valve to regulate the pressure of the egr system. Egr temp sensor diagnostics toyota 4runner forum largest.
We will be discussing the easiest way to test the 3 remaining components. On some vehicles, the obd ii system may monitor the operation of the exhaust gas recirculation system. I figure this solution, especially for those of us that are picky about how things look, might be nice to have during our testing and diagnosis of egr related problems like the. The egr valve in photo 3 of 4 with the red x is not covered by this article and is tested differently. But the baro sensor also affects your fuel to oxygen ratio. Standard motor products vp1t egr valve position sensor. A suitable scanner can assist in testing this type of egr valve by using the scanner program to activate the solenoid and also monitoring the feedback signal.
One of the more troublesome tasks this tool makes easy is diagnosing the latest versions of egr with valve position sensors, such as the ford evp sensor. Symptoms of a bad or failing egr temperature sensor. Repair information is becoming scarce and inconsistent for all vehicles, but is even worse for these bosch fuel systems, isuzudesigned engines. In my car at least, egr flow is tested by looking at the manifold pressure, so if the map sensor is screwy, that could be it. Duramax engines are not designed and produced by the manufacturer that sells them. Get free help with trouble code diagnosis, output sensors wiring issues and much more. Testing egr systems exhaust gas recirculation pt 2. Egr diagnostics car obd diagnostics, ecu chip tuning.
O2 oxygen sensor function failure symptoms testing. After miles of service, the exhaust gas recirculation egr systemespecially the egr valvewill lead to engine performance problems due to carbon buildup, components mechanical problems, or vacuum hose leaks. The ecm commands the egr valve and the vgt actuator positions to control the amount of exhaust gases entering the engine. The on board engine computer determines the position of the. An in depth look at the function and testing of the egr valve and automotive exhaust gas recirculation systems. Great deal, has everything except the two bolts that hold the egr valve to the intake manifold. Also vehicles of this vintage typically have electronically actuated egr. Inspect harness and connector and service as necessary.
Most diy mechanics should be up to the task of replacing an egr valve and it doesnt usually require a lot of specialist equipment. Consequently, this results in the reduction of nitrogen oxide emissions. Its an integral part of the diesel emission system on all diesel engines 2007 and newer running on the road today. A vacuumcontrolled egr valve is easy to test with a handheld vacuum pump see the image.
Follow these procedures for using either piece of test equipment. I run down to the auto zone and get the codes read, p2495 exhaust gas recirculation egr cooler bypass flap position sensor. Key onengine off fuel primer pump electric fuel pressure 15 psi 103 kpa at test port a. The differential pressure feedback exhaust sensor, or dpfe sensor, is part of the vehicles exhaust gas recirculation egr system. We use a mirror to check the 19851991 egr valves operation. This prevents the valve from malfunctioning and allowing too much exhaust into the intake manifold at one time. In a diesel engine, opening and closing the egr valve with a scan tool or a vacuum pump. As a concerned driver, you must be aware of the symptoms of a bad egr. It helps those gases to return to the combustion chamber instead of directing them to the exhaust emission system. In particular the 5wire linear egr valve used on many different gm vehicles.
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