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Re: code 35 on 1991 ford f250 5.8l
There is a little aluminum block with 2 hoses on it that goes to the exhaust manifold. If you take that sensor off and replace it, that will fix your problem. it's called a PFE sensor. They get corroded up inside. Make sure you clean the hoses out when you replace the sensor and hook them up the same way you took them off. Don't cross the hoses. Hope this helps. Phil
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have you removed the egr and checked for plugged in the egr port or damage to the egr itself... i think it's more of a flow issue associated with the position of the egr and not the solenoid itself... koeo/koer tests are a pain even with a break out box... good luck as this year (early 90's) of Ford's are the worst for diagnosing computer/running issues
This code indicates a problem with the EGR valve's pintle position. The
EGR Valve's pintle could just be stuck in which case the problem could
be fixed by cleaning the EGR valve.
If the EGR valve is
electronically controlled or cleaning the valve does not fix the
problem, you will most likely have to replace the EGR Valve.
Keep in mind that the EGR valve relies on inputs from other sensors to
determine the pintle position. If one of these other sensors is not
operating correctly, it could be giving you a false P1406 error code.
P1405 is an EGR code this can be caused by a bad EGR valve and vaccum selonoid and or a bad DPFE sensor and blocked or melted hoses going to the DPFE.I usally remove the EGR Valve and using a hand held vaccum pump ck the Valve to see if it opens correctly if it is then ck the DPFE hoses if they are ok . Now if the EGR valve is bad You need to replace the DPFE and the Selonoid and the valve because the Valve not working burns them up internally. If the Valve is good first replace the selonoid ... its the cheapiest .... if that doesn't fix it replace the DPFE and the hoses going to it . If you know some one with a good Scan tool it may have a EGR self test prcedure built in like mine does and makes this easier but if not i have told you how with out a scanner
There are several codes that can be set by the EGR system. EGR valve failures on Fords are very rare. There is usually something wrong with the EGR Control Solenoid, The EGR ports clogged up, The DPFE sensor (the sensor that monitors the EGR system) or the vacuum lines between the intake manifold and the control solenoid or between the solenoid and the valve.
Fault codes NEVER tell you what parts to replace. They only tell you which engine management system is failing to function properly. Anytime there is a fault code the system has to be diagnosed to find out what is causing it to not operate like it should. You can spend a lot of money on parts and not fix your EGR system if proper diagnosis is not performed.
If the gasket for the EGR valve is leaking it will cause your engine to idle very high and will cause the computer to set "lean O2 sensor" codes. If this is not occuring, it is safe to assume that the EGR gasket is not a problem.
There are many things that can cause your engine to die at a stop light. Everything from a loose battery terminal to a failed computer module to a bad ignition switch, to a malfunctioning Idle Air Control (IAC) valve or an intermittent problem with a Crankshaft Position Sensor. I would recommend having it checked out by a professional if it continues to be a problem.
The EGR valve can be tested with a Vacuum pump. If the diaphragm is bad, the valve will not change positions. Hence the error Code for the position sensor not opening to allow the valve to work. And the error code for the pressure sensor not registering a change in pressure because the EGR valve did not work.
So both sensors can give a false Code. On the other hand, you will see both sensors have Vacuum lines and electric connections. When the electricity is switched on, vacuum is suppose to flow back to the EGR Valve. That is why the first thing you do is test the EGR Valve to see if the diaphragm is broke.
If the EGR valve holds pressure it should be okay. Then you would want to check for pressure in the lines coming off of the switches. Remember to clear the onboard computer each time you replace a part, or you will get 25-35 Startups worth of false information.
Both Autozone and Oreillys will scan or clear your car for free. I hope you find my solution very helpful. You usually don't have a complete failure of all 3 parts at the same time.
A code P0401 most likely means one or more of the following has happened:
The DPFE (differential pressure feedback EGR) sensor is faulty and needs to be replaced, this is the common cause
There is a blockage in the EGR (tube), most likely carbon buildup
The EGR valve is faulty
The EGR valve may not be opening due to a lack of vaccuum
In fixing this code, it is quite common for people to just replace the EGR valve only to have the OBD code return. The EGR valve is not always the culprit.
Use a vacuum pump and pull the EGR valve open while monitoring engine RPM's & DPFE voltage. There should be a noticable difference in RPM's with the EGR open
Clean out the EGR valve and/or tubing to remove deposits
Check the voltage at the DPFE, compare to specified values (refer to a repair manual for your specific model)
Replace the DPFE sensor (with a good quality / OEM one)
Replace the EGR valve
There may be no visible symptoms to the driver. Poor fuel mileage, possible misfire, depending on O2 sensor position when sticking.
A code P0136 may mean that one or more of the following has happened:
Faulty O2sensor leak in exhaust close to O2 sensor, faulty O2 sensor is the common cause.
Short to voltage on O2 signal circuit
Open in circuit resistance caused by corrosion in connector