The always on CEL...

[pat julian]

My '96 2.3 had the Cel on the entire time I owned it..despite installing just about every sensor and egr valve on the truck..didn't make any difference..just lived with it..The CEL on my '93 2.3 manual is also coming on..My question is how do you read the codes since it is OBD1..I know you use the test plug under the hood..but what is the procedure ?? Or is there an OBD1 code reader I can buy..I have an OBD2 reader here...Thanks in advance...

 

[Mark_88]

You can check out this article in the Tech Library (aka Tech Articles) and if you have the light you an read the codes from the flashes or use the Volt Meter...

http://www.therangerstation.com/tech_library/OBD_I.html

I've never actually had to do this (yet) so I have no idea how much of a process it is (time wise)...but you can also check the codes that are posted in the same section...there are 2 and 3 digit codes so you may need a pen and paper if there is more than one code.

 

[pat julian]

Stopped by Orielly's had had the cel checked..code 332..EGR system..I know from past experience it could be the EGR valve..or something in that circuit..clogged ports..maybe..Ranger has according to previous owner 149,000...Could possibly be a DPFE sensor..according to the archives here..Does the '93 have a DPFE sensor ?? It will idle with no CEL...but drive off and within 100 yards the light comes on..also..it has a minor miss..is the miss related to the problems I mentioned..or another issue ?? The 332 code was the only one shown..Thanks...Need all the advice I can get for this old man..

 

[Mark_88]

Check the vacuum line on the EGR before doing anything...a broken vac line can cause rough idle among other things...and sounds like the EGR simply isn't responding properly (opening)...if that is not the case...probably dirty EGR tube that is preventing the gases from entering the TB.

I found the below information on another site to help explain things...and there is a ton of information on this in previous posts if you care to search...

Since you did not get a DPFE code (not sure what years had these) I would say it is probably related directly to the EGR...such as it is plugged up with gunk...which is way more common than a sensor failure...

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
• 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

Possible Solutions

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

I would say it is probably easiest to check the EGR and vac lines first...just take care when removing the nut...and spray it down good before attempting to crack it free...PB Blaster works good...and having something like a bottle brush to clean inside the fitting is a good idea...but try to pull that stuff out if you find any...it is like thick paste and burns really good and smokey...

 

[pat julian]

Thanks...I've had a lot of experience with EGR'S and clogged tubes as that is a common problem on the geo metro I drove for 600,000 miles..however the Ranger idles fine..and runs smoothly..even though I can tell it has a slight miss..seems to be sluggish..but runs 70.75..80mph smoothly..I checked th gas mileage today on my 75 mile round trip commute...30 mpg at 60-65 mph..I'll check the EGR valve and associated lines and tube..and see if that clears the miss as well as the CEL..Thanks