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Discussion Starter · #1 ·
97 2.5 5 speed. out wheeling yesterday, coming down a very steep Rocky slope, used 4low to slow me down on the decent. it nearly stalled a time or two going over rocks but I used a bit of throttle and got down. when I reached the bottom I looked down and saw the check engine light was on. took it straight to AutoZone checked code, it came up MAP sensor low input, according to the guy. (they wont let you read your own codes at our AutoZone) he cleared it and said if its running fine don't worry. well im taking it on a trip (1400 miles round trip) next month. if its going to become a problem I'd like to fix it now. what do you guys think?
 

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MAP sensor measures vacuum in engine. If you come close to stalling while accelorating your vacuum goes low and can throw a MAP code.
 

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Given the scenario, the CEL was likely a fluke. I would take no action unless the DTC recurs. Worst case, MAP sensors are neither hard to find nor difficult to replace.
 

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Discussion Starter · #4 ·
thanks guys. im New to these more modern fuel injection setups. im more used to my old 89 yj or 75 dj. getting better though with help.
 

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No worries on the CEL in that type of situation, it happens simply because the engine is operating in a temporarily unusual mode. The light will turn off by itself. That scared me too the first time it happened to me. :)
 

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Discussion Starter · #6 ·
ok. so anybody know if those $40 code readers at AutoZone are any good. that way I can just check it myself anywhere. on trail etc.
 

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ok. so anybody know if those $40 code readers at AutoZone are any good. that way I can just check it myself anywhere. on trail etc.
They work. And for more money, you can get one that actually reads out the sensor data live…and recommends corrective action. Best $135 I have spent in a while. Mine has paid for itself many times, assisting friends and neighbors. (The diagnosis is free, but the repair isn't.)

If I didn't already have one, I would be all over this:

http://www.ebay.com/itm/ACTRON-CP95...044?pt=LH_DefaultDomain_0&hash=item4d05b648bc
 

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ok. so anybody know if those $40 code readers at AutoZone are any good. that way I can just check it myself anywhere. on trail etc.
Your '97 has the ability to display its own DTCs (diagnostic trouble code) for free. Simply cycle the ignition switch on-off-on three times within five seconds and then wait for any store codes to start displaying in the odometer. If you did the procedure correctly, you will always get at least the '55' code which only means no more codes follow.

This link definies the various DTC code meanings... 1980s Chrysler, Plymouth, and Dodge computer fault codes
 

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97 2.5 5 speed. out wheeling yesterday, coming down a very steep Rocky slope, used 4low to slow me down on the decent.
Which is the correct way to descend a steep hill.

when I reached the bottom I looked down and saw the check engine light was on. took it straight to AutoZone checked code, it came up MAP sensor low input, according to the guy. he cleared it and said if its running fine don't worry.
This same thing happens to my '98 Sport 5-speed. There is a local mine tailing that, when I descend it in 4LO 2nd gear with my feet off the pedals, the engine holds ~2400 RPM while I crawl down it. This generates a lot of engine vacuum, substantially more than I would see any other way. After perhaps ten seconds of this, the computer decides that this unusual voltage output from the MAP sensor means something must be wrong, so it trips the check engine light and also fattens up the fuel mixture so much that it smells like I suddenly have a fuel leak (again, the computer thinks there is a major malfunction). As soon as I'm down the hill, the vacuum returns to the normal range along with the voltage output from the MAP sensor... and now that the computer sees a normal MAP signal, the fuel mixture also returns to normal. The CEL will remain lit for another 10 or 12 engine starts, but eventually is decides that all is well and it turns off the CEL on its own.

So, yeah, you have nothing to worry about.
 

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My '04 gives me an evap leak code on occasion. Mine is due to the gasket on my fuel cap being a bit dried out. i pull the cap, wet\lick my finger and get the grit off the gasket, put the cap back on and clear the code by pulling the neg terminal on my batt. Only happens once ever few months so being poor, and a tight wad, I put off replacing the fuel cap. :)
 
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