Hello, I would like to first apologize if this is something that has been posted before. I have tried to search for a post that had the same symptoms but have failed, so am starting a new post. Recently my alternator had started to die. The usual suspects, ABS lights, parking brake lights, engine shutting off/cutting off but starting again, showing a low charge across the batteries. This had all happened before so I am not new to alternator related problems on the VZ. So rather getting a secondhand alternator this time. I decided to get it reconditioned. I work as a mechanic and we have a guy that reconditions alternators. I did not have the battery light prior to this. So I changed the alternator, he provided me with the 243, which is the 120amp version. Started up the car, it was charging great between 14.1-2 with all the lights and aircon on. But the battery light came on. So thinking it was the problem with the 120amp version, I gave him my old alternator for it to be reconditioned, installed it and same problem. Actually worse. Battery charges great but shuts off and on while driving, abs lights etc, same signs as a dying alternator. My boss and alternator guy says it's the relay, an auto elec recons it's the alternator done wrong. I read on the forum that it may be a bad earth. If it is the relay is there anybody that can pinpoint me to it? I can't seem to find anything online. Also I've done my best to trace all the earth points and checked the points, but I may have missed a few, are there any diagrams showing where all the earth points are? I have another alternator that is sitting in my garage, one I changed over a year ago, to see if the alternator light comes on, just to make sure it is not the alternator, before I spash the cash to buy a new one. I would appreciate any suggestions. Thanks in advance!
The 243 Holmart is the smart system alternator for VE which is controlled by the ecm and also monitored (current output) by the BCM, so having a wrong Alternator would do that having no internal regulator.
Hello thank you for your inputs. Because I suspected the 243 alternator as well, I gave the reconditioner my old alternator. After installing it, it has given me the same problem. So can I suspect that he did not do it right?
Not much to them, I be looking at your wiring to see if there any breaks in the line, what about your battery plus terminals and wires? You say your a mechanic this is basic stuff, have you plugged it in for a scan?..
I have read in other forums that batteries on the way out may cause this problem, so I got a new one. Connections all good, wires look good too, don't see any breaks in them. Thank you for your inputs! Really appreciate it!
He could be a retired mechanic that isn't across all those fangled new lectronic type gismos (PS: i liked when an alternator had internal or extenral regulator and was connected to the battery without smarts involved...)
Wasn't the vz a non-smart system? What is the voltage is it like dropping after awhile or staying steady all the time. If its a smart system then on a full charged battery the alternator will start off under 14v like 13.6v not the usual 14.4v like the conventional alternator. See if there any fault codes, something might be shorting out putting the light on. If its working and regulating then it be a bad sender wire or computer glitch.
The ECM monitors the voltage but does not regulate it like it does in the VE. It does have an internal regulator. The 120amp alternator can be run on any VZ without issue. It (120amp) was an option available for the VZ, and factory fitted to Telstra and Police vehicles. Check the fusible link.
The charge is at 14.1~3v When I turn all the electronics on, it drops only a little and goes back to a steady 14.1v. The DTC shows P0625 Generator field/F terminal. I should have been more detailed. My apologies. It only showed this code the one time when I had the 120amp alternator installed. Other times there are no codes at all. I do not think it is a smart system (I assume you mean clutch activated? Like the ones on european cars). I also forgot to mention the battery light goes away at high revs. This is unfortunately also when the car cuts out .
In the VF the alternator, which GM calls a generator, is controlled by the BCM. The BMC gets information from a current sensor at the battery and uses an algorithm to calculate remaining battery capacity. Since the BMC knows the remaining battery capacity along with the BMC’s knowledge of other power consumption states (lights, aircon, ect), it can determine how much juice the generator should push into the electrical system and commands it to do just that. Smart system, which simply means changing the battery to something other than recommended may not allow the algorithm to work as intended. I think VE is similar in its alternator ‘smarts’ to the VF but (I think) VZ is a dumber system. I liked the dumber systems for the freedom it provided and which worked rather well with appropriately battery maintenance.
Have you checked the terminals and the plugs? Any shorts, loose terminals, corroded terminals, dirty terminals? Check fusible link.
Hi guys, Sorry for the late update. I just got home from work and put in the old alternator. I haven't done anything else. There is no alternator light now. So I guess it is safe to assume that the recon wasnt done right :/
