Kittamaru Posted May 29, 2010 Share Posted May 29, 2010 So, my fathers '94 Jeep Grand Cherokee Laredo has become my DD while I do some body work and other repairs on the pathy... however. On the way home from our anniversary trip, the CEL came on and my power meter was dipping down to around 9V. I feared the alternator, but being a '94 we had no way to check (not OBD2)- keeping the RPM's higher made the power meter come back up to 14V, but it would slowly slide back down, forcing me to rev to (holy @!*%) over 4500 rpm (which, in 5th gear, would have been around 120 or so MPH I think). In the end, I made the last 100 or so miles of the trip in 3rd gear just to keep the damn thing powered... Anyway, pulled the codes via the light blink test (got a book for it) and got the following two codes: Code 12 - Battery Power to PCM was disconnected (Problem with battery connection. Direct battery input to PCM disconnected within the last 50 ignition key cycles) Code 41 - Problem with Charging System (Occurs when battery voltage from the auto-shutdown relay is below 11.75 volts) but we did NOT get code 47, Charging System Voltage Too Low... So... yeah. Confused as all hell... all connections looked good to me, and the voltage regulator is built into the PCM, so I hope to god that isn't it... Looking for some advice on what/where to start, as I can't afford not to have a vehicle while I fix the pathy! Link to comment Share on other sites More sharing options...
pathfinderfisherman Posted May 30, 2010 Share Posted May 30, 2010 hey kit i got a buddy who is all jeep all the time....I'll see if i can catch him at home...(he don't have a phone) he'll probably be able to say something....and i'll get back 2 ya Link to comment Share on other sites More sharing options...
Kittamaru Posted May 30, 2010 Author Share Posted May 30, 2010 Thanks man, I appreciate it! ATM the Jeep is my DD while I do the work on the Pathy... so yeah, atm, I have no vehicle lol. I'm charging the battery every night to get me to and from work, but I know that can't be good for the battery and I'm sure it'll stop working on my soon Link to comment Share on other sites More sharing options...
silverton Posted May 30, 2010 Share Posted May 30, 2010 Take it to a shucks (oreilly's) or autozone have them test the charging system, they should have a tester to do it while it's all in the vehicle. Link to comment Share on other sites More sharing options...
Kittamaru Posted May 31, 2010 Author Share Posted May 31, 2010 I had Adv. Auto do so, and they said it was the alternator because of the fact only 12 volts were being put out... however, it will put out 14 at any RPM if I exceed a certain RPM, which makes me think something else is mucked up - is there any way to test JUST the alternator output (before voltage regulator or anything else?) Link to comment Share on other sites More sharing options...
pathfinderfisherman Posted May 31, 2010 Share Posted May 31, 2010 Ok ol' boy says if all your wiring is clean at connections it is either in the alty (voltage regulator) or a dead cell in batt. most likely for the 41 code....... then I found this about the 41 code...... "I would trace the wires assigned to the field coils of the alternator because that is what the 41 code is referring to. Basically, one of the four wires at the alternator should have 12V applied on it when you turn the ignition switch to "run"; that is the source of voltage for the field coil. Then another wire should go to the engine controller, and that one should oscillate due to the controller's action between 0V and 12V which is what modulates the field coil so that the output of the alternator averages at around 14v when the engine is turning it over. The other two wires are a fat ground and of course the fat 12v wire to the battery directly. The code is saying that there is a short (presumably to ground) on either of those first thinner two wires so that there is no magnetic field being established in the field coil. I hope you can sort out the wires without having the color codes"............ He said the 12 could be a dead cell batt too.... to check batt, and alty then reset the ecu and check after running 10 min.........#1 disconnect the positive battery cable off the the battery and ground it to the negative battery cable for a least 30 sec.... #2 Reinstall positive battery cable....#3 Turn on the ignition on but do not start.....#4 Turn head lights on for 30 sec. then turn them off....This should reset your computer.Then recheck your codes. then while I was poking around I found this http://autorepair.about.com/library/faqs/bl561g.htm ..... it seemed nice to me I hope it helps Link to comment Share on other sites More sharing options...
Kittamaru Posted May 31, 2010 Author Share Posted May 31, 2010 Oh wow... uhm... *rubs neck* I hate to say it, but that is just a little bit over my head 0o' Maybe I'm just tired - I'll take another look in the morning, check the jeep, and report back Link to comment Share on other sites More sharing options...
Kittamaru Posted June 10, 2010 Author Share Posted June 10, 2010 Well, long story short - the alternator was overheating and the windings were actually expanding and pulling away from the armatures. I asked my mechanic WHY that would happen, and his response was basically "Well, the truck IS 16 years old - the coatings that are supposed to prevent that have worn away" To which I replied "Well, then why doesn't it happen to my Pathfinder? Older, more miles, and more strenuous use?" To which he said simply "Good ole' American Engineering", pointing at the Jeep (a Chrysler vehicle). DOH! Link to comment Share on other sites More sharing options...
Kingman Posted June 10, 2010 Share Posted June 10, 2010 I'm surprised to hear the alternator is failing. 4.0L and the asian warner transmissions run forever though. If it's the V8, watch out for when your oil pressure suddenly tanks to 0 PSI when you come to a stop and the warning light, and audible dinger, come on. Link to comment Share on other sites More sharing options...
87pathy Posted June 10, 2010 Share Posted June 10, 2010 you need a new alernator, do't even screw around. as i stated in another thread, if your down to 9VDC and nothing is on, its your alt. Link to comment Share on other sites More sharing options...
Tungsten Posted June 10, 2010 Share Posted June 10, 2010 YOU NEED A NEW TO MAKE THE JEEP AGAIN Link to comment Share on other sites More sharing options...
Kittamaru Posted June 11, 2010 Author Share Posted June 11, 2010 Oh, it's already BEEN replaced lol. I just thought ya'll would get a kick knowing just how superior Pathfinder parts are to Jeep parts. Still, though, one thing bothers me - why would the ECU give a "charging system malfunction" code and NOT the "charging system low voltage" code? Link to comment Share on other sites More sharing options...
Tungsten Posted June 11, 2010 Share Posted June 11, 2010 Oh, it's already BEEN replaced lol. I just thought ya'll would get a kick knowing just how superior Pathfinder parts are to Jeep parts. Still, though, one thing bothers me - why would the ECU give a "charging system malfunction" code and NOT the "charging system low voltage" code? Why? Its a Chrysler. You should be lucky it GAVE you a code. Link to comment Share on other sites More sharing options...
Kittamaru Posted June 11, 2010 Author Share Posted June 11, 2010 Eh... true... Link to comment Share on other sites More sharing options...
Kingman Posted June 11, 2010 Share Posted June 11, 2010 I'd find out who exactly makes certain parts for different vehicles before blaming the auto maker that uses parts from these manufacturers, before assuming the nameplate has anything to do with it. It's like auto makers who use Tremec and Borg Warner transmissions, they fail a lot and have a lot of common problems...it's not the particular auto maker it's the supplier. Same with Delco-Remy brand electrical parts, you'll find A TON of bad alternators from them that are in many different vehicles. Today I just replaced an alternator on a Suzuki Samurai that uses this brand, but what's weird is some Chryslers, GMs, Freighliners, Detriots, etc. use these. Hell Jeep Cherokees use a Japanese brand transmission and there are quite a few failure points on those as well. Link to comment Share on other sites More sharing options...
olddirtyrake Posted June 11, 2010 Share Posted June 11, 2010 Oh, it's already BEEN replaced lol. I just thought ya'll would get a kick knowing just how superior Pathfinder parts are to Jeep parts. Still, though, one thing bothers me - why would the ECU give a "charging system malfunction" code and NOT the "charging system low voltage" code? You may have a bad ground. I had the same problem with a Mitsubishi I had. The battery ground was grounded to paint, They figured the metal screw going into the metal would be good enough. Well in the salt belt we have a little thing called rust that plagues everything. And there grounding bolt had enough rust on it to screw there ground frying the alternator. I scraped the paint to metal and reground, grabbed a scrap yard alt and walla problem fixed. Its problems like that that get me $2000 cars for $400 and make me a little cash. Link to comment Share on other sites More sharing options...
Kittamaru Posted June 11, 2010 Author Share Posted June 11, 2010 I'd find out who exactly makes certain parts for different vehicles before blaming the auto maker that uses parts from these manufacturers, before assuming the nameplate has anything to do with it. It's like auto makers who use Tremec and Borg Warner transmissions, they fail a lot and have a lot of common problems...it's not the particular auto maker it's the supplier. Same with Delco-Remy brand electrical parts, you'll find A TON of bad alternators from them that are in many different vehicles. Today I just replaced an alternator on a Suzuki Samurai that uses this brand, but what's weird is some Chryslers, GMs, Freighliners, Detriots, etc. use these. Hell Jeep Cherokees use a Japanese brand transmission and there are quite a few failure points on those as well. it's still the auto-makers fault... for using parts that have a penchant for failing Link to comment Share on other sites More sharing options...
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