P1637 after alternator replacement
06-07-2013, 11:09 AM
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P1637 after alternator replacement On my 2002 Z28...
After my power steering pump leak finally killed my alternator, I replaced both of them. Started the car and alternator is charging at 14.5V, however, the car is now throwing a P1637 code. I've read just about every related thread for P1637 and all point back to the "little red wire" on the alternator. If the wire connection is bad, it shouldn't be charging, right? I've tried clearing the code but it comes right back again. Car runs fine otherwise.
Side note and may be related somehow?:
Installed new clutch and CATS, O2 sensors about a month ago. Couldn't get CATS out without snapping the 3 rusted bolts on the bottom of the exhaust manifolds and too tight to get in there and heat up with a torch. My bright idea was to unbolt entire assembly (Manifolds and CATS together) so I could remove the bolts using torch without snapping them (worked fine, BTW).
Problem was that two header bolts snapped on drivers side head. One was still out far enough to grab with vise grips, the other snapped flush with head. Consequently, had to remove manifold and head to repair header bolt thread on one bolt hole.
Okay, I get everything back together and car started and runs fine. With new CATs and O2 sensors, CAT DTF's go away, but now get a P0107 code (MAP sensor). I checked harness for 5v reference signal and it was okay. Checked the sensor with voltage meter and it was okay too. Replaced MAP sensor for Sh*** & Giggles. Tried erasing code. Still comes back. Checked for vacuum leaks - none found.
Lastly, got C0240 (PCM Traction Control not allowed). I can sometimes erase this code for about a minute, but it come right back. Checked third brake light as per posts I found. Light works fine.
P0107 & C0240 codes apppeared together upon start up after head and manifold installation. I've checked all the grounds, including the three behind the drivers side head, made sure no wires were crimped or cut and I'm beginning to wonder if this is more of a PCM problem that went bad while the car was sitting for about a month with the battery disconnected?
BTW, the P1637 code is new since replacing the alternator.
Any help would be appreciated.
After my power steering pump leak finally killed my alternator, I replaced both of them. Started the car and alternator is charging at 14.5V, however, the car is now throwing a P1637 code. I've read just about every related thread for P1637 and all point back to the "little red wire" on the alternator. If the wire connection is bad, it shouldn't be charging, right? I've tried clearing the code but it comes right back again. Car runs fine otherwise.
Side note and may be related somehow?:
Installed new clutch and CATS, O2 sensors about a month ago. Couldn't get CATS out without snapping the 3 rusted bolts on the bottom of the exhaust manifolds and too tight to get in there and heat up with a torch. My bright idea was to unbolt entire assembly (Manifolds and CATS together) so I could remove the bolts using torch without snapping them (worked fine, BTW).
Problem was that two header bolts snapped on drivers side head. One was still out far enough to grab with vise grips, the other snapped flush with head. Consequently, had to remove manifold and head to repair header bolt thread on one bolt hole.
Okay, I get everything back together and car started and runs fine. With new CATs and O2 sensors, CAT DTF's go away, but now get a P0107 code (MAP sensor). I checked harness for 5v reference signal and it was okay. Checked the sensor with voltage meter and it was okay too. Replaced MAP sensor for Sh*** & Giggles. Tried erasing code. Still comes back. Checked for vacuum leaks - none found.
Lastly, got C0240 (PCM Traction Control not allowed). I can sometimes erase this code for about a minute, but it come right back. Checked third brake light as per posts I found. Light works fine.
P0107 & C0240 codes apppeared together upon start up after head and manifold installation. I've checked all the grounds, including the three behind the drivers side head, made sure no wires were crimped or cut and I'm beginning to wonder if this is more of a PCM problem that went bad while the car was sitting for about a month with the battery disconnected?
BTW, the P1637 code is new since replacing the alternator.
Any help would be appreciated.
06-09-2013, 08:32 AM
#2
The P1637 is for the "L" terminal which I believe is the thin regulator wire on top, not the charge wire. The thin wire is very easy to damage during an alternator swap on F-Bodies.
However with all the other oddness you mentioned I would ask if your harness has any cuts, bare spots in it or is a ground wire off somewhere? If all the grounds are connected and you have no cut or touching wires, have you tried a spare PCM? One of my projects kept giving me a cylinder 5 misfire code so I swapped the PCM with a spare I had laying around after trying all the usual stuff but before spending money. A quick flash with the proper calibration and my problem was sorted. Moving that PCM to another vehicle - misfire cylinder 5.
Just some ideas...
However with all the other oddness you mentioned I would ask if your harness has any cuts, bare spots in it or is a ground wire off somewhere? If all the grounds are connected and you have no cut or touching wires, have you tried a spare PCM? One of my projects kept giving me a cylinder 5 misfire code so I swapped the PCM with a spare I had laying around after trying all the usual stuff but before spending money. A quick flash with the proper calibration and my problem was sorted. Moving that PCM to another vehicle - misfire cylinder 5.
Just some ideas...
01-30-2017, 10:53 PM
#3
12 Second Club
Bumping this to the top since it has lots of nice search terms related to my 'problem'. But I'll add a few more because P1637 is weird.
P1637 on my car never goes away. But just now started experiencing problems that affected drive-ability that may or may not be related. No engine light. no other pending codes or anything. I have EFIlive and am a 10+ year member and I think I can figure this out but I want to add to the knowledge base as well. It's just a frost tune bolt on car. But I can't log when I'm experiencing the problem...
2000 pontiac trans am runs and drives just fine except for hot starts after refueling re-fueling (as of recent). it takes several (5-10 cycles of the starter) to stumble to life. embarrassing. literally stumble. sounds like it has a wicked *** cam when it does come to life which leads me to believe it's air related but not so much. Sounds like it has no spark but damn it's hard to tell it could be fuel. I also have different keys and it does the same with all of them. Runs and looks fine data wise once it starts from what I can tell kinda but its too late by the time its running to retrieve data. I noticed the SES light didn't come once the last time I experienced this issue (i fixed a v6 with this same issue). Which leads me to believe something isn't right electronically. The radio kicks off when restarting too and I remember a time when it didn't but anyway.
Restarts when hot are fine but it will idle down to sub 500 then pick back up and be normal.
I replaced alternator 2k miles after fuel pump (50k miles ago; at 215k).
Voltage on gauge seems low with key on engine off (just above yellow) now.
Voltage on gauge seems above normal / average after engine start but not alarming (safely below red).
Car has no charging problems.
Prior to alternator change I would get a random ABS and AIR BAG light when really WOT hanging it out. I haven't seen that for a long time but picked up the airbag light not too long ago after refueling and getting on it a little.
For a few years this damn car would not like to take fuel at the pump. Would always have to finagle the trigger on the dispenser while it clicked off multiple times. Just recently it decided it was happy and hasn't clicked off in months except for once.
O2 sensor LTFT seem to always go to -2.6 or something like that across the board even after 1000's of miles. odd.
Prior to any of these issues long ago I fixed vacuum / PCV type stuff that is typical of these cars. I don't suspect any problem there or I would see it in logs
I replaced the MAF about 35k miles ago for fun.
I dunno.
Is it the little wire that goes into the alternator? Do I need to replace more of that wire in case it is compromised? I made sure the connection was good but that wire is really skimpy and fragile looking. But I wonder if more is wrong.
Any similar related knowledgeable advice is appreciated.
P1637 on my car never goes away. But just now started experiencing problems that affected drive-ability that may or may not be related. No engine light. no other pending codes or anything. I have EFIlive and am a 10+ year member and I think I can figure this out but I want to add to the knowledge base as well. It's just a frost tune bolt on car. But I can't log when I'm experiencing the problem...
2000 pontiac trans am runs and drives just fine except for hot starts after refueling re-fueling (as of recent). it takes several (5-10 cycles of the starter) to stumble to life. embarrassing. literally stumble. sounds like it has a wicked *** cam when it does come to life which leads me to believe it's air related but not so much. Sounds like it has no spark but damn it's hard to tell it could be fuel. I also have different keys and it does the same with all of them. Runs and looks fine data wise once it starts from what I can tell kinda but its too late by the time its running to retrieve data. I noticed the SES light didn't come once the last time I experienced this issue (i fixed a v6 with this same issue). Which leads me to believe something isn't right electronically. The radio kicks off when restarting too and I remember a time when it didn't but anyway.
Restarts when hot are fine but it will idle down to sub 500 then pick back up and be normal.
I replaced alternator 2k miles after fuel pump (50k miles ago; at 215k).
Voltage on gauge seems low with key on engine off (just above yellow) now.
Voltage on gauge seems above normal / average after engine start but not alarming (safely below red).
Car has no charging problems.
Prior to alternator change I would get a random ABS and AIR BAG light when really WOT hanging it out. I haven't seen that for a long time but picked up the airbag light not too long ago after refueling and getting on it a little.
For a few years this damn car would not like to take fuel at the pump. Would always have to finagle the trigger on the dispenser while it clicked off multiple times. Just recently it decided it was happy and hasn't clicked off in months except for once.
O2 sensor LTFT seem to always go to -2.6 or something like that across the board even after 1000's of miles. odd.
Prior to any of these issues long ago I fixed vacuum / PCV type stuff that is typical of these cars. I don't suspect any problem there or I would see it in logs
I replaced the MAF about 35k miles ago for fun.
I dunno.
Is it the little wire that goes into the alternator? Do I need to replace more of that wire in case it is compromised? I made sure the connection was good but that wire is really skimpy and fragile looking. But I wonder if more is wrong.
Any similar related knowledgeable advice is appreciated.
