What are the results of the GM EGR valve test?

Check engine light (CEL) will be shining nice and bright. P0401 EGR System Flow Insufficient. P0403 EGR Solenoid Control Circuit. P0404 EGR Open Position Performance. P0405 EGR Position Sensor Circuit Low Voltage. Rough idle. Really bad gas mileage.

What does p0404 mean on an EGR sensor?

Often times code P0404 does not actually indicate that there is something wrong with the EGR valve itself, but actually that the EGR sensor is telling your PCM that the proper amount of EGR needed to flow back into your cylinders and cool them is not present.

How many wires are in an EGR valve?

There are 5 wires sticking out of the EGR valve’s connector, in this section we’ll explore what each one does. Most of the EGR valves will have the letters A thru’ E molded onto the EGR valve’s connector. I’ll be using these same letters for the circuit descriptions below: Ground circuit for EGR valve solenoid. Gray with Black stripe wire.

How to reset check engine light, free easy way?

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Why does my dpfe have a leaking EGR valve?

You now know the DPFE, EGR valve and tube and hoses are okay and we can move on to test the EVR (EGR Vacuum Regulator), part of the system. If the reading did not change, then you could suspect a leaking EGR valve, allowing uncommanded flow of exhaust gases.

How does a delta pressure feedback EGR work?

These hoses go to the EGR tube and there is an orifice in that tube between the locations where the hoses branch out. The sensor uses the difference in pressure between these two hoses to determine exhaust flow through the tube (thus the term Delta Pressure Feedback EGR).

What kind of EGR valve does GM use?

Before we jump in head long into this article, you need to know that there are two types of electronic EGR valves that GM uses in most of their late model vehicles. The EGR valve that’s covered by this article are for 3.1L, 3.4L, and 3.5L GM vehicles from 2000 to 2009 models years (although some late 1999 models use this type of EGR valve too).

What does the EGR error code p0401 mean?

In the shop’s defense, replacing your EGR valve probably would eliminate the error code, turn off the CEL, and allow you to pass emissions inspection. One thing is certain: the P0401 error code specifically means you have “reduced flow” in your exhaust gas recirculation system.

When to worry about an EGR valve problem?

If the initial reading is in spec but you have a trouble code for this system then it is possible that the system is not flowing when expected (EGR valve, EGR tube, DPFE hoses or control side issue), is flowing when it shouldn’t be (EGR valve or control side issue) or you may have an intermittent concern, possibly even with the DPFE sensor.

Do you need to change your EGR code?

Sure, the technician scanned the error code, but just because it means your EGR is failing, doesn’t mean it needs to be replaced. Unfortunately, sometimes shop owners force their technicians to take the simplest, most obvious route rather than spending extra hours diagnosing a problem more thoroughly.

Why is EGR important to the p0401 code?

Usually on an OBD2 system that sets the P0401, the ECM/PCM must see the failure on two consecutive trips before it will permanently set the code and trigger the Check Engine Light. The EGR system is important because it reduces emissions by allowing burnt exhaust gas to flow back into the engine.

Why does O2 sensor drift rich during EGR flow?

Pre-OBD2 GM vehicles will watch O2 sensor activity while the ECM is commanding EGR flow, because O2 sensor readings will drift slightly rich when EGR is flowing due to the displacement of oxygen by the inert exhaust gas entering the intake.

How to clean the EGR system in your car?

How to clean the egr system. EGR system cleaning and carbon removal in your car DIY with Scotty Kilmer. Low flow trouble code P0401. How to clean carbon build up in the EGR system to fix check engine light and trouble code P0401. DIY car repair with Scotty Kilmer, an auto mechanic for the last 43 years. 1.

How does the p0405 code work on the EGR sensor?

The information from the EGR position sensor is sent to the PCM which then decides the flow of exhaust gasses depending on how much the EGR valve opens. If the PCM calculation does not match with the data transmitted by the sensor, the P0405 code triggers.

What is the diagnostic code for a Chevy check engine light?

Remember, these are manufacturer specific codes only. Refer to our Generic OBD II code list for definitions on all other Chevy diagnostic trouble codes. Manufacturer Specific Codes P0342Camshaft Position Sensor A Bank 1 Low Input – Related Information P1031HO2S Heater Current Monitor Control Circuit Sensors 1

What should the resistance be on the EGR sensor?

If the EGR valve in your car is vacuum actuated, perform the bench-test of the position sensor using a vacuum pump and a DMM. Remove the connector and measure the resistance across the whole circuit and the reading should be around 6 kΩ.

Why is there an EGR code on my Ford?

However, we often find EGR codes on Ford products caused by inexpensive plastic parts that falsely report position to the control module. Several technical service bulletins for a wide variety of different makes and models have documented different problems associated with the EGR valve system.

What should I do if my EGR light is not working?

The repair of this condition is removal of the EGR valve and inspection of the passageway to check for a blockage. Each model vehicle has different procedures for clearing the passageway due to many different configurations of the system. Some Fords have a removable tube.

What is the code for the EGR valve?

You should measure at least 10 kΩ between VC, EGLS, E2, and body ground. Repair as necessary. Code is P0406, EGR flow Sensor A Circuit High Input. I know what the EGR is, not sure how to fix.

What does the EGR sensor on an ECM do?

The ECM also uses sensors to monitor system function, such as the EGR Temperature or Flow Sensor and EGR Position sensor. If the ECM detects a problem in the EGR position sensor circuit, it will set a diagnostic trouble code (DTC) and illuminate the malfunction indicator lamp (MIL). What are the common causes of code P0406 ?

What’s the code for an EGR valve throw?

What code will an EGR valve throw have? The P0401 trouble code is related to your car’s exhaust gas recirculation (EGR) system, which controls an engine and reduces emissions. Suppose a computer-controlled valve gives a certain amount of gases back into your engine to be burnt with the air-fuel mixture.

What kind of EGR valve does a GM 3100 have?

In particular the 5-wire Linear EGR valve used on many different GM vehicles. The car being tested has a 3100 engine in it. (3.1L) This engine is notorious for have problems with plugged EGR passages in the intake manifold. Also these electronic EGR valves will stick in both the open and closed positions.

Why do I not feel pressure on my EGR valve?

You should feel vacuum or a slight pressure on your finger tip, depending on the particular system type. If you don’t feel a change in vacuum or pressure, likely the problem lies with the circuit that provides vacuum or pressure to the valve. Reconnect the vacuum hose to the valve.

How to test an EGR valve, a simple procedure?

Connect a hand vacuum pump to the EGR valve in place of the vacuum hose and apply 15 in-Hg of vacuum to the valve (if you don’t have access to a vacuum pump you may borrow-rent one from a local auto parts store). As you apply vacuum to the valve, check for diaphragm movement.

How does the ECM know when EGR is flowing?

When EGR is flowing, the pressure will rise in the hose connected below the orifice and drop in the hose connected above it, thus the Engine Controller (ECM/PCM, etc.) can determine if EGR is flowing and how much.

When do I blank off the EGR valve?

The engine code may need to be reset. After 3-5 times of switching the car on and off, the code should reset by itself if the original fault is fixed, but not always. I personally blank off EGR valves to prevent damage to the butterfly valves on the inlet manifold.

What is the EGR code for insufficient flow?

The code relates to flow from the EGR to the intake. Remove EGR and throttlebody and clean the ports with intake cleaner and a scribe or snake. Also check for leaking gaskets or lines but usualy the system is just CLOGGED with hard carbon. Remove clog and flow will return and your light will not come back on. Loading…

Where is the entry port for the EGR valve?

Clean out the entry port. The entry port is where the valve tubes connect to the engine (usually the intake manifold) while the EGR valve is off. Reinstall the EGR valve.

What are the results of the GM EGR valve test?