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dead pedal issues

davidj_31
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davidj_31

davidj_31

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Having a dead pedal issue on my 2002 24v auto. codes are p0122 p0236 p1475. problem is very intermittent. New apps sensor after confirming all apps power grounds and signals were good. when i have a pedal map and apps reading are were they should be, when problem is occurring map voltage is maxed out and apps signal is all over the place.  Initially thought  short between apps wiring and map wiring, could not find such short and did not notice change during wiggle test of harness nor could i measure continuity between apps and map circuit. Starting to think bad ecm, the problem did start after bleeding my low pressure fuel system getting diesel all over driver side of engine.   Fuel pressure is good. If anyone could help that would be great. 

Haggar

Haggar

Posted
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The combination of your errors.  (5v sensor supply too high, boost sensor range/performance, apps low input)  just screams wiring or one of the sensors on the 5v rail.

 

When you clear the codes, how quickly do they return?  do they all come on together?

 

diesel won't hurt the ECM..  We have all dumped fuel there.  But the wiring connection to your ecm could be dirty.   I would disconnect it and clean it very well with electrical contact cleaner.  Inspect all of the pins for corrosion.  I use a dielectric grease when I re-assemble to displace air and hopefully keep moisture out.

 

Your issue really sounds like one of the sensors on the 5v rail has perished.  (its an expensive part, but the map sensor seems to cause all kinds of problems like this when it buys the farm)

 

just my $0.02  HTH

Hag

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davidj_31

davidj_31

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Thank you for replying, resistance check on all my sensors on the 5 volt were good and receiving power under 5 volts(about 4.5v) which is why  im a bit confused on why its throwing the aux 5 volt high, being an intermittent issue i guess i could've measured the map resistance at the wrong time. After clearing issue and codes can come back after a few minutes or right away.  connector is clean and i put new dielectric grease o after pulling the the connector for continuity and short checks. ill definitely check the map again. thank you  

davidj_31

davidj_31

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just checked that ground all good, just did some more checking, key on engine off apps circuit works fine, when running cuts in and out thinking wiring issue is there a ground i can check for the ecm?

i dont know if i mentioned this earlier but the issue started about 10 min after installing my lift pump.

dripley

dripley

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Just add a little to the mix, while messing with my MAP sensor I noticed that it has its own 5v signal from seperate pin in the ECM. The oil pressure shares that wire pre 2002. The other sensors are fed the 5v off of a different pin in the ECM. Do both of these wires share the 5v source in the ECM?

dripley

dripley

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8 minutes ago, davidj_31 said:

From what i see on the 2002 diagram the map and oil pressure share the 5 volt and the apps has its own

That is correct by the wiring diagram. That is not the case in the wiring harness at least for the 02's. They only have an oil pressure switch that requires one wire only. It only tells the ECM when the engine has pressure and the ECM takes over the OP gauge based on rpm and ECT readings, same as the 3rd gens from what I have read. It is that way on my early 02 and the spare 02 harness that I have. 

davidj_31

davidj_31

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So my apps issue and map issue are unrelated unless issue is internal in the ecm? becuase both signals go out at the same time when problemm is occuring

Haggar

Haggar

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Sorry  work has been busy.

 

Here is the schematic of the splice for the grounds for the 5v sensor circuit.  Dripley has a picture of this.  Now this is an 01 FSM.  Dripley is certain his 02 is similar to this, but the oil pressure sensor does not require this ground and is not part of this diagram.  but as far as we can tell all the other sensors are like this drawing implies.  ( the Fiat guys could have tricked us again though....  I swear its an Italian plot  :whistle2:)

 

Dripley has a picture of the splice location in the harness.   This splice is definitely right where you banged around messing with a lift pump. 

 

GL  HTH

 

Hag

2001 FSM Ram 8W-70-7.pdf

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dripley

dripley

Posted
Posted (edited)

Here you go.

20190417_184755.jpg.a311cba8bc57adec39bfc1c83493d6cc.jpg

Matter of fact if you look at the bottom of the picture just left of center and hanging down below the orange wire is the oil pressure connector. Might not be obvious but there is only one wire to it.

Edited by dripley
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