You Won't BELIEVE Why this Dodge Doesn't Start...

hi everyone welcome back to pine hollow out of diagnostics today i made the drive to harrisburg pennsylvania about two hours from state college and we got called in here on a 2005 dodge durango so all right the name of this garage is good karma garage and jeff here he repairs cars it's kind of a what is it jeff like a goodwill you know low income well we're exactly yeah we're repairing cars for um inspection doing the inspection work for them for uh lower income families uh no cost to them we get them wow for inspection okay all right so this is for a good cause so i'll definitely give jeff a good discount here maybe the youtube revenue will help pay for this diagnosis so what is up with this uh dodge durango 4.7 liter v8 and customer complaint originally was uh crank nose start right jeffy start correct yep and then you guys replace the fuel pump you did yeah um and then it did it make it better did it run still crank no start uh-huh and you said the codes that it's setting is a p0068 and a p what was it the zero one two three zero one two three having to do with the tps sensor and then there's some measurements the voltage was weird and this thing you know they tried a new computer so this is a replacement computer here uh i'm assuming it wasn't programmed to the to the vehicle it was programmed okay so it's programmed to the vin uh and it's still a crank no start now i got it to fire up just once here scanned it for codes so the only code that we have is a p0068 manifold pressure throttle position correlation very interesting i'll show you what it does so if you just crank it sounds like a very fast crank like i don't know are we losing compression maybe it's uh you know cylinder wash or whatever if you give it a little gas sometimes it fires up sometimes it does not you can hear the fuel pump run and it's not setting any other codes so this is instantly video worthy here this is not going to be there it is you know the zero zero six eight read fault code information engine oil pressure sensor circuit low p0068 there it is throttle position sensor one circuit high okay very interesting so let's go right into our freeze frame or i'm sorry the data stream and see what we're reading on this tps all right so i've got some data pits pulled up here just the basics coolant temp 51 degrees that seems about normal engine speed zero injector pulse width map vacuum map volts is 4.4 so if it drops into a vacuum i assume that's going to go down mass airflow minimum tps throttle position sensor percent 100 crazy minimum tps is 1.2 so yeah right off the bat why do we have four volts on our tps sensor what is going on with this throttle body um we can take a look at the throttle bite to do a visual inspection let's see if we press the gas pedal my gas pedal is all the way down look what happens to the voltage there it goes and now it's at 102 crazy stuff 108 percent and then it goes to 30 even though the voltage keeps going up calculated tps voltage is 2.14 4.2 so yes something indeed does not make sense this should be like half a volt right now with the gas pedal the pre or released now is this a cable system or is it an electronic throttle body it is a cable system okay now we can this is i guess just hanging out so this is our throttle body that's our tps and jeff did you uh do some wiring modifications or repairs we didn't hear any repairs there we just checked that that had a um um you know we took off the factory tape okay yep yep and you said you actually did a bypass check right to the computer with the signal wire correct okay and that didn't change anything okay great so regular mechanical throttle body what could go wrong with this tps sensor just for kicks i'm going to unplug it see what the voltage does so just a little push yep there we go so it goes to five volts okay and plug it back in 4.15 volts okay and this is like a limb home mode if you lose your tps it'll say hey you're at 30 throttle and basically not let you you know rev it too too high so let's just we can get a volt meter measure the voltages and all these three wires get a wiring diagram and see what we're missing um i'm thinking we might be missing a ground here since this it looks like it's a pull down sensor you know because the default is 5 volts so the voltage isn't coming from the sensor to the computer is basically being pulled down from the computer through the sensor to one of these wires the other one should be a five volt reference all right so we have our voltage that the computer sees and here's my voltmeter now i got it hooked to battery negative here make sure your negative lead is always on the battery negative terminal and i'm just checking my meter yep we got 12.3 volts so we can trust our readings and now let's just check these three pins on the tps sensor connector with with the sensor unplugged so the leftmost pin 11 millivolts now we can always use a test light to see if that's a good ground so if we go from battery positive we find the ground that test light will light if i touch the pin test light is lighting and our voltage is pulled up to 55 millivolts that's good now middlewire 4.7 volts and the reading on our scanner changed as well let me see if you guys can see that right there so that might be the signal wire we don't know and it went back up and then right here is a 5 volt reference okay great so let's go back to the signal pin here 4.7 volts when i'm measuring it with my meter let's see what happens when i pull it up with a test light now this won't hurt anything i just want to see what the maximum reading is that the computer can see maximum we can read is 5 volts even though our meter is showing 12. okay now let's pull it down with a test light so tesla battery negative now tesla is not lighting and indeed our sensor voltage goes down to let's see here get a good contact on there exactly zero volts so i don't see anything wrong with the signal wire maybe the computer is trying to check the integrity if i take my test light off it goes back to 4.7 now when we plug this sucker in we checked all the wires all the wires are good when we plug it in we have 4.15 volts that is not a good reading so as of now the only thing i'm suspecting is a bad tps sensor now jeff was the tps sensor replaced that's the second one i put on okay do you have the original oh i do not do you have any other replacements i do know all right so let's back probe the signal wire just to see if the computer is reporting the correct voltage it is 4.13 that is definitely not an appropriate voltage here now there's you can't really mess up the installation there's only one way you can go on there pretty much okay so let's pop off that sensor play around with it see what's going on all right so tps sensor is off i'm just bouncing it around here look what our voltage is doing it's all over the place sometimes it's like .2 sometimes it's you know one up to three and the meter agrees so this is definitely a problem let's try to turn the little knob inside of there see what happens to our voltage focus you guys in on the screen there so here's our sensor so throttle body goes counterclockwise so you see the voltage is 4.7 i release it 4.5 3.8 why does it drop out right there that's terrible this sensor is completely junk i mean 3.3 volts and then it just drops to zero for no reason like right there that's not a pin fitment issue this is inside the sensor now this is from napa you said right jeff correct complete junk well we can see if there's a chrysler dealer anywhere in the vicinity see if they have one of these but man that's we check the pins the pins look you know decent we can do a drag test on there insane the problem is right here so i'm doing a quick drag test here with the aes wave terminal kit and these pins they definitely have some preload some tension and the voltage is rock steady when you know when the sensor's not hooked up so what we could do is hook up a variable resistor and trick this voltage just you know something reasonable and see if the truck fires up all right so we got our decade box hooked up and this thing can um you can make the resistance very high so this is ten thousand i got it set to 90 plus nine so 100 000 ohms to 100 kilo ohms and that raised the voltage here to a steady one volt now let's reset the codes here minimum tps is 1.2 that's a learned value there so the cars will still might be confused but let's let's just reset the codes clear fault code yes okay refill code again and it shouldn't set any circuit codes right now okay no dtc's good so now let's just fire it up and see if it fires up notice i'll make sure that none of my leads are in the way of the fan there's my test plate put that over here okay should be should be good see if it does anything different so key off key on perfect right let's try again kion like butter what do you think jeff the best that's ever sounded like all right so we called the dealer up and asked them how much is an oem sensor do they have one in stock they have one in stock it's over a hundred dollars the one in apple was like 25 so like hey that's why it doesn't work because it's junk so we'll plug in brand new tps sensor oem this truck should be fixed okay so pretty cool that the minimum tps you can see a relearn so it relearns on each key cycle we're at 1.0 volts with the decade box plugged in and it's happy it thinks that zero percent so uh what i want to do now is actually plug in the original pcm make sure everything is appropriate there and then uh you know we don't need this remand pcm right you probably can't send it back but i'd rather the car run on its original engine computer alright so i got the original pcm reinstalled let's see if the truck fires up scan it for codes [Music] perfect [Applause] so what's the moral of the story here if you're going to load up the parts cannon at least load it with good ammo for electronics do not i repeat do not buy aftermarket junk it will cause you to go down a rabbit hole i mean this truck didn't need a computer i don't know if it needed a fuel pump or not perhaps it did but it needed an oem tps sensor apparently when the guy got it here in the garage it already had been replaced probably the junk unit he tried two more they're all junk apparently napa you know it fits but it doesn't work what's the point of even selling that junk so uh once we put in the new tps sensor we'll verify that it works and then we should be done all right we got an oem tps sensor made in the usa sweet even has a little gasket on it so let's uh once we plug this in our voltage should be appropriate we can you know spin it by hand or uh manipulate it any which way so there you go 0.1 volts and if we spin it let's see this this way yep goes up to four volts comes back down very nice and repeatable perfect i like it let's put it on the truck so the tps kit here came with a new gasket and a new o-ring that's why you're paying 100 bucks and let's see if it actually works i should fit right in let's put the bolts in so looks like our minimum voltage there is 0.3 1.4 right about there yeah about half a volt that's that's normal all right so our voltage goes from 0.4 to 3.7 i think that's reasonable let's put this air box back on and fire it up one more time all right so key on [Music] here's the rev up fine go into our pcm make sure there's no new code stored and we can look at if the minimum tps got saved no dtc's let's read some data so was it minimum tps mass airflow map vacuum now it does not have a mass airflow sensor so that's a calculated value throttle position percent throttle position voltage target idle speed let's try those yep .43 is minimum tps now if i press the gas yes our percent seems to be running pretty well 19 inches of vacuum see key off key on and let's push the gas pedal all the way to the floor see if our data comes back after a key cycle here there we go so all the way down the floor yep 108 percent that's that's fine 3.7 volts on the tps i love how it estimates the mass airflow there fire it up one more time perfect sweet i think we're done so that's it pretty straightforward but if a part is bad and you assume it's good remember it new new never ever works especially if it's an aftermarket electronic part that's the lesson of the day all right thanks all for watching we'll see you next time bye

Channel: Pine Hollow Auto Diagnostics

Views: 255,571

Keywords: dodge, chrysler, no start, crank, TPS, computer, signal, diagnostics, bypass, test, guess, parts, aftermarket, junk

Id: wGQm0E8ANVI

Length: 21min 47sec (1307 seconds)

Published: Tue Dec 14 2021