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check engine light on, ford ranger

randyhjackson's Avatar
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06-09-04, 03:54 PM   #1  
check engine light on, ford ranger

I am needing some help on this one. My check engine light has been coming on so I took it down to the neighborhood Autozone to get the codes checked. I had a code 172 and 335. I was told by the guy at autozone that it was the EGR valve and the crankshaft position sensor. My repair manual states that the 172 means too rich fuel and the 335 means voltage out of range for the PFE. It also states that if this is the case then the PCM is to blame and needs to be replaced.

I need advise on this one. The PCM is pricey so I want to make sure before I replace it. The ERG sensor was replaced last month. As far as a crankshaft sensor, my truck does not miss, backfire, cut out or any of the above. The truck again is a 1994 Ford Ranger 2wd, 4 cyl.

Last edited by randyhjackson; 06-09-04 at 07:15 PM. Reason: misspelling
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billys68ss's Avatar

Join Date: May 2003
Posts: 1,459

06-09-04, 07:17 PM   #2  
Actually 172 code refers to a lean condition. Check to see if you have any vacuum leaks before you try throwing any parts at it. Most likely the rear oxygen sensor if they are original, but you should go through the steps first. Fords are bad about having vacuum hoses get soft and collapse. Check all of your vacuum lines carefully, especially the PCV system That PCV valve is a bear to get to so it may have never even been replaced.
The 335 code refers to the EGR Valve pressure sensor having a voltage high or low condition. This is most likely a bad Differential Pressure Sensor. But at the same time the first code could be partially to blame for this as a very large vacuum leak can cause all kinds of codes to set.
Hope this is helpful to ya,

You said that the guy at Auto Zone told you that one of your codes refers to a crankshaft position sensor. That would be the case AFTER 1996 but not on this vehicle. The only downside to getting your codes read at one of these places is that they use a generic code reader. It isnt really even a scan tool. They can read codes, but cant give you a real diagnosis to your problem. Prior to 1996 all codes were either 2 or 3 digit numbers depending on the manufacturer. After 1996 when OBDII was introduced and all (almost) codes had to be standardized the you have a "P" code with 4 digits after it that refer to powertrain codes. These codes are designed to let you know that you have an engine/emissions related concern. There are other codes that can set the CEL to on, such as "B" codes for Body which is your radio, power door locks and your SRS system. Then there are "C" codes for Climate Controls. This one is pretty self explanatory. There are also "U" codes, but to be honest I have never seen one and cant find an actual explanation of them so I am not going to speculate on their design.
Sorry I dragged this out so far but it is really useful information for the novice.
Hope this is helpful to ya,

Desi501's Avatar

Join Date: Oct 2003
Posts: 2,207

06-10-04, 03:45 AM   #3  
Posted By: billys68ss There are also "U" codes, but to be honest I have never seen one and cant find an actual explanation of them so I am not going to speculate on their design.
Billy, The "U" codes are bus communication codes.

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