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12-13-2013, 09:57 PM | #1 |
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alternator question
I'm getting the following DTC codes for the alternator:
[] P0621 - Generator L-Terminal Circuit (Pending) (History) (Current) (Immature) [] P0622 - Generator F-Terminal Circuit (Old) (History) (Current) (Immature) Ok, here's my setup: I have a speartech harness that has a 2 wires plug going into the alternator (red and grey). The alternator is a 2004 Silverado 145 amp alternator (internally regulated). Since it's internally regulated, can I turn these codes off? TIA
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Rob - https://www.instagram.com/hart_rod_c10 As Iron Sharpens Iron, So One Man Sharpens Another. Proverbs 27:17 FOR SALE: DBW pedal bracket - http://67-72chevytrucks.com/vboard/s...d.php?t=651123 FOR SALE: Hood Brackets http://67-72chevytrucks.com/vboard/s...d.php?t=679945 1987 Silverado SWB - 34.5K original miles http://67-72chevytrucks.com/vboard/s...d.php?t=801834 1969 SuperBurb - http://67-72chevytrucks.com/vboard/s...d.php?t=200387 1968 Farm truck - http://67-72chevytrucks.com/vboard/s...d.php?t=358692 1968 SWB - http://67-72chevytrucks.com/vboard/s...d.php?t=551258 1948 Chevy - http://67-72chevytrucks.com/vboard/s...=122164&page=3 |
12-13-2013, 10:15 PM | #2 |
meowMEOWmeowMEOW
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Re: alternator question
Take a look and see if the 1st plug wire is close to the alternator at all. It can actually cause fault codes if its too close. If your running a standard copper plug, you might wanna look at the generator voltage at idle, which you can change. Sometimes with copper plugs and aftermarket wires, they will draw more than the ecu wants to allow without thinking there is an electrical fault.
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12-13-2013, 10:41 PM | #3 | |
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Re: alternator question
Quote:
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Rob - https://www.instagram.com/hart_rod_c10 As Iron Sharpens Iron, So One Man Sharpens Another. Proverbs 27:17 FOR SALE: DBW pedal bracket - http://67-72chevytrucks.com/vboard/s...d.php?t=651123 FOR SALE: Hood Brackets http://67-72chevytrucks.com/vboard/s...d.php?t=679945 1987 Silverado SWB - 34.5K original miles http://67-72chevytrucks.com/vboard/s...d.php?t=801834 1969 SuperBurb - http://67-72chevytrucks.com/vboard/s...d.php?t=200387 1968 Farm truck - http://67-72chevytrucks.com/vboard/s...d.php?t=358692 1968 SWB - http://67-72chevytrucks.com/vboard/s...d.php?t=551258 1948 Chevy - http://67-72chevytrucks.com/vboard/s...=122164&page=3 |
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12-14-2013, 03:22 AM | #4 |
meowMEOWmeowMEOW
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Re: alternator question
I imagine it may, but I'm looking to see if there is another cause. I don't wanna turn off codes that may help show a REAL problem, just incase...since then we'd ignore the real issue if the code no longer would pop.
If its the inherent cause, then ya turning it off will "solve" it, though I don't think that code itself will cause any tuning or mechanical issues.
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12-14-2013, 12:34 PM | #5 | |
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Re: alternator question
Quote:
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Rob - https://www.instagram.com/hart_rod_c10 As Iron Sharpens Iron, So One Man Sharpens Another. Proverbs 27:17 FOR SALE: DBW pedal bracket - http://67-72chevytrucks.com/vboard/s...d.php?t=651123 FOR SALE: Hood Brackets http://67-72chevytrucks.com/vboard/s...d.php?t=679945 1987 Silverado SWB - 34.5K original miles http://67-72chevytrucks.com/vboard/s...d.php?t=801834 1969 SuperBurb - http://67-72chevytrucks.com/vboard/s...d.php?t=200387 1968 Farm truck - http://67-72chevytrucks.com/vboard/s...d.php?t=358692 1968 SWB - http://67-72chevytrucks.com/vboard/s...d.php?t=551258 1948 Chevy - http://67-72chevytrucks.com/vboard/s...=122164&page=3 |
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12-14-2013, 12:44 PM | #6 | |
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Re: alternator question
Quote:
So, long story short, this setup doesn't work without the GBCM and BCM and you need to turn off the codes you asked about. That's assuming that your Speartech harness is wired to run the 2004 alternator with the internal regulator and not trying to control it with the ECM. |
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12-14-2013, 01:02 PM | #7 | |
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Re: alternator question
Quote:
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Rob - https://www.instagram.com/hart_rod_c10 As Iron Sharpens Iron, So One Man Sharpens Another. Proverbs 27:17 FOR SALE: DBW pedal bracket - http://67-72chevytrucks.com/vboard/s...d.php?t=651123 FOR SALE: Hood Brackets http://67-72chevytrucks.com/vboard/s...d.php?t=679945 1987 Silverado SWB - 34.5K original miles http://67-72chevytrucks.com/vboard/s...d.php?t=801834 1969 SuperBurb - http://67-72chevytrucks.com/vboard/s...d.php?t=200387 1968 Farm truck - http://67-72chevytrucks.com/vboard/s...d.php?t=358692 1968 SWB - http://67-72chevytrucks.com/vboard/s...d.php?t=551258 1948 Chevy - http://67-72chevytrucks.com/vboard/s...=122164&page=3 |
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12-14-2013, 01:39 PM | #8 |
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Re: alternator question
I'm going to use "2007-up alternator" in my example, but I'm referring to any alternator with a PWM (pulse width modulated) voltage regulator. The exact year that a particular platform went to a PWM voltage regulator depends on whether we're talking cars/trucks/vans/etc. To my knowledge, all Gen IV application originally came with this type regulator.
The 2007-up alternator is controlled via a PWM signal from the e38, but the control lines from the ECM to the alternator are ECM outputs. The input side of the equation is from the BCM/GBCM setup that I described above. Most swaps can't accomodate that since it's not "normal" to include the BCM in a swap. So, there are two options: 1) Run the original 2007-up alternator wired to the ECM with the 2 factory control lines (exact pin numbers may vary by application but I can look up a specific year/model if you let me know what donor we're talking about). With this option, the alternator will default to 100% duty cycle (13.8 volts) and throw alternator DTCs. You'll need to disable the codes. 2) Run a 2004 style alternator. The e38 cannot control the type of regulator in this alternator directly, so you still need to turn off the DTCs for the alternator. The difference is in the wiring. The regulator on the alternator will have 4 pins; "P","L","I/F", and "S". You'll need to hook up two of the terminals: "L" needs to go to an idiot light or a 470-ohm 1/2 resistor. The other side of the light/resistor needs to go to a switched 12V supply (i.e. hot with the ignition on). The "S" terminal needs to go to 12V hot at all times. Either method will work. The argument can be made that option 2 is better because the regulator is actually "regulating" and not defaulting to 100% duty cycle, but you have to buy a new alternator. I personally went with option 1 on the 2007 LY5 (e38 ECM) swap that I finished up last week. |
12-14-2013, 02:04 PM | #9 | |
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Re: alternator question
Quote:
Edit: How do I verify that my harness is wired one way or another? If I check the voltage key off, the L and F wires have 0 voltage. With the key on, L has 0 voltage and F has 12 volts....I also forgot to mention that I am not using a BCM.
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Rob - https://www.instagram.com/hart_rod_c10 As Iron Sharpens Iron, So One Man Sharpens Another. Proverbs 27:17 FOR SALE: DBW pedal bracket - http://67-72chevytrucks.com/vboard/s...d.php?t=651123 FOR SALE: Hood Brackets http://67-72chevytrucks.com/vboard/s...d.php?t=679945 1987 Silverado SWB - 34.5K original miles http://67-72chevytrucks.com/vboard/s...d.php?t=801834 1969 SuperBurb - http://67-72chevytrucks.com/vboard/s...d.php?t=200387 1968 Farm truck - http://67-72chevytrucks.com/vboard/s...d.php?t=358692 1968 SWB - http://67-72chevytrucks.com/vboard/s...d.php?t=551258 1948 Chevy - http://67-72chevytrucks.com/vboard/s...=122164&page=3 Last edited by Hart_Rod; 12-14-2013 at 02:15 PM. |
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12-14-2013, 02:41 PM | #10 | |
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Re: alternator question
Quote:
You can verify how your wiring is set up by unplugging the ECM and the alternator and "ohm-ing" out the wires with a voltage meter. If the alternator wires run to the PCM, that won't work for a 2004 alternator. You'll need to run the wires from the 2004 alternator as I described above to get it to regulate correctly. |
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12-14-2013, 02:57 PM | #11 |
meowMEOWmeowMEOW
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Re: alternator question
This poses the interesting question; if its wired for ecm regulation, but it already regulated at the alt, and you shutoff the ecm control for reg, then does it really need to be re-wired? (whereas I can see if you put an un-regulated alt on a gen III, you'd end up possibly frying things)
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12-14-2013, 03:07 PM | #12 | |
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Re: alternator question
Quote:
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12-16-2013, 01:54 AM | #13 | |
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Re: alternator question
Quote:
I never had to address the issue myself, so I can't say for sure how the computer would react to setting the value that low. It can always be changed back, so there really isn't a risk in trying before making hardware changes.
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12-16-2013, 06:21 PM | #14 | ||
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Re: alternator question
Quote:
Quote:
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Rob - https://www.instagram.com/hart_rod_c10 As Iron Sharpens Iron, So One Man Sharpens Another. Proverbs 27:17 FOR SALE: DBW pedal bracket - http://67-72chevytrucks.com/vboard/s...d.php?t=651123 FOR SALE: Hood Brackets http://67-72chevytrucks.com/vboard/s...d.php?t=679945 1987 Silverado SWB - 34.5K original miles http://67-72chevytrucks.com/vboard/s...d.php?t=801834 1969 SuperBurb - http://67-72chevytrucks.com/vboard/s...d.php?t=200387 1968 Farm truck - http://67-72chevytrucks.com/vboard/s...d.php?t=358692 1968 SWB - http://67-72chevytrucks.com/vboard/s...d.php?t=551258 1948 Chevy - http://67-72chevytrucks.com/vboard/s...=122164&page=3 |
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12-14-2013, 04:59 PM | #15 |
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Re: alternator question
Here's a picture of my alternator setup:
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Rob - https://www.instagram.com/hart_rod_c10 As Iron Sharpens Iron, So One Man Sharpens Another. Proverbs 27:17 FOR SALE: DBW pedal bracket - http://67-72chevytrucks.com/vboard/s...d.php?t=651123 FOR SALE: Hood Brackets http://67-72chevytrucks.com/vboard/s...d.php?t=679945 1987 Silverado SWB - 34.5K original miles http://67-72chevytrucks.com/vboard/s...d.php?t=801834 1969 SuperBurb - http://67-72chevytrucks.com/vboard/s...d.php?t=200387 1968 Farm truck - http://67-72chevytrucks.com/vboard/s...d.php?t=358692 1968 SWB - http://67-72chevytrucks.com/vboard/s...d.php?t=551258 1948 Chevy - http://67-72chevytrucks.com/vboard/s...=122164&page=3 |
12-14-2013, 05:03 PM | #16 |
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Re: alternator question
Is this how the 2004 alternator should be wired?
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Rob - https://www.instagram.com/hart_rod_c10 As Iron Sharpens Iron, So One Man Sharpens Another. Proverbs 27:17 FOR SALE: DBW pedal bracket - http://67-72chevytrucks.com/vboard/s...d.php?t=651123 FOR SALE: Hood Brackets http://67-72chevytrucks.com/vboard/s...d.php?t=679945 1987 Silverado SWB - 34.5K original miles http://67-72chevytrucks.com/vboard/s...d.php?t=801834 1969 SuperBurb - http://67-72chevytrucks.com/vboard/s...d.php?t=200387 1968 Farm truck - http://67-72chevytrucks.com/vboard/s...d.php?t=358692 1968 SWB - http://67-72chevytrucks.com/vboard/s...d.php?t=551258 1948 Chevy - http://67-72chevytrucks.com/vboard/s...=122164&page=3 |
12-14-2013, 06:08 PM | #17 |
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Re: alternator question
The short answer is "no". I think you have the plug labelled backwards. If you unplug the harness from the alternator, the plug on the alternator is part of the actual voltage regulator. The housing of the plug should literally be marked "P" "L" "I/F" and "S" on the side that has the locking tang for the connector. It looks like the terminal that you labelled "S" is actually "P".
After you verify that they are labelled backwards, here is the function of each terminal. "P" (pulse) is not used. It connects internally to the stator and provides a pulse signal that varies with alternator RPM. "L" (lamp) is the charge indicator circuit. It goes to an idiot light or a resistor (470 Ohm 1/2 watt is a good value) "I/F" (ignition/field) goes to 12V ignition (i.e. hot with key on) "S" (sense) goes to B+ (hot at all times). You can run the wire to a remote location (like the main fuse box feed) to regulate charging based on the voltage drop that occurs through the wiring, but the regulator will use the internal sense circuit if you leave it disconnected. If you're just going to run a wire down to the battery post, you may a well just let the internal sense do it's thing because there is effectively no voltage drop at the alternator BATT terminal. Here's what I suspect is going on with the way that you have it wired right now: It charges, but the e38 isn't getting feedback from the GBCM and is throwing codes. The e38 is defaulting the duty cycle of the alternator to 100% (13.8 V). This isn't necessarily bad, but the regulator really isn't regulating. It just maintains 13.8 V regardless of the total system current draw. If it were mine, I would wire it as follows: Take the wire from the "L" terminal and route it to an idiot light (if you have one or a 470 Ohm 1/2 resistor if you don't). The other side of the bulb/resistor should go to a switched 12V source (i.e. hot with the ignition on) Take the wire from the "I/F" terminal and run it directly to a switched 12V source. Forget the "S" wire (that you don't have) for now. In order to run the two wires, you'll probably have to depin them from the ECM connector although it is possible that they are already connected this way inside the harness. You'll just have to look at the harness and possibly ohm them out with a meter to verify. EDIT: Just for clarification, the short version of what I'm trying to get across is that the e38 controls the alternator based on GBCM input. Without a GBCM and BCM, the alternator is never going to work as GM intended (although it will work at 100% duty cycle). By wiring it as I outlined above, it will regulate the voltage depending on load completely outside of ECM control. Then you just turn off the DTCs in the ECM and use your voltage gauge/idiot light to monitor the alternator's function. Last edited by dayj1; 12-14-2013 at 06:14 PM. |
12-14-2013, 08:43 PM | #18 |
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Re: alternator question
OOpppsss! DayJ, I had my label backwards. I think it's wired like you said. I'm just waiting on verification from John at Speartech. Now I just need to figure out these 2 codes, .
[] P057C - (SES) (Pending) (Old) (History) (Current) (Immature) [] P2537 - Ignition Switch Accessory Position Circuit Low (Old) (History) (Current) (Immature) Thanks for all of your help!!
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Rob - https://www.instagram.com/hart_rod_c10 As Iron Sharpens Iron, So One Man Sharpens Another. Proverbs 27:17 FOR SALE: DBW pedal bracket - http://67-72chevytrucks.com/vboard/s...d.php?t=651123 FOR SALE: Hood Brackets http://67-72chevytrucks.com/vboard/s...d.php?t=679945 1987 Silverado SWB - 34.5K original miles http://67-72chevytrucks.com/vboard/s...d.php?t=801834 1969 SuperBurb - http://67-72chevytrucks.com/vboard/s...d.php?t=200387 1968 Farm truck - http://67-72chevytrucks.com/vboard/s...d.php?t=358692 1968 SWB - http://67-72chevytrucks.com/vboard/s...d.php?t=551258 1948 Chevy - http://67-72chevytrucks.com/vboard/s...=122164&page=3 |
12-15-2013, 12:46 AM | #19 | |
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Re: alternator question
Quote:
Unfortunately, P2537 doesn't even show up in the reference material that I have. Here's a description of the brake pedal circuit from GM: DTC P057C Brake Pedal Position Sensor Circuit Low Voltage Circuit/System Description The brake pedal position (BPP) sensor is part of the engine brake pedal override feature. The engine control module (ECM) continuously monitors the vehicle speed and the position of the brake pedal. These two main inputs, along with other ECM inputs are used to determine if the vehicle is decelerating at the proper speed and rate with the brake pedal applied. When the engine brake pedal override system is active, the ECM reduces engine torque to assist in reducing vehicle speed. The BPP sensor is a three wire sensor, connected to a 5 V reference circuit, a low reference circuit, and a signal circuit. The ECM supplies 5 V to the BPP sensor, and also provides a sensor ground path on the low reference circuit. The BPP sensor sends a voltage signal to the ECM on the signal circuit. The voltage on the signal circuit will vary from a voltage greater than 0.25 V when the brake pedal is released to a voltage less than 4.75 V when the brake pedal is fully applied. I found this part interesting as well. I think you would probably notice the underlined part Action Taken When the DTC Sets DTCs P057B, P057C and P057D are type A DTCs. Engine torque is reduced to 50 percent of available engine torque. Brake torque management is active at 25 kpa (3.7 PSI) of brake pedal apply press |
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12-14-2013, 09:10 PM | #20 |
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Re: alternator question
Great info dayj1 you have a pm
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12-15-2013, 01:24 PM | #21 |
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Re: alternator question
Great info DayJ! John from Speartech confirmed that my harness was wired like the truck one above (including the resistor for the lamp light). I turned off those 2 codes. It's really weird that the P2537 code pops up. It's not even listed in the DTC of HPTuners.... As far as the 057C code, makes me wonder if I should just turn the Brake Torque Management off in the tune? Here's a pic. Thanks as always!
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Rob - https://www.instagram.com/hart_rod_c10 As Iron Sharpens Iron, So One Man Sharpens Another. Proverbs 27:17 FOR SALE: DBW pedal bracket - http://67-72chevytrucks.com/vboard/s...d.php?t=651123 FOR SALE: Hood Brackets http://67-72chevytrucks.com/vboard/s...d.php?t=679945 1987 Silverado SWB - 34.5K original miles http://67-72chevytrucks.com/vboard/s...d.php?t=801834 1969 SuperBurb - http://67-72chevytrucks.com/vboard/s...d.php?t=200387 1968 Farm truck - http://67-72chevytrucks.com/vboard/s...d.php?t=358692 1968 SWB - http://67-72chevytrucks.com/vboard/s...d.php?t=551258 1948 Chevy - http://67-72chevytrucks.com/vboard/s...=122164&page=3 |
12-15-2013, 01:48 PM | #22 | |
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Re: alternator question
Quote:
I finally found P2537. Check the transmission connector, pin 9. It was dark blue in the factory harness and is supposed to be 12V when the ignition is on. The code is tripped whenever the TCM doesn't see the voltage for over a minute. |
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12-16-2013, 07:41 PM | #23 |
meowMEOWmeowMEOW
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Re: alternator question
You and your damn dropdown menu's.
So convenient.
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12-16-2013, 07:42 PM | #24 |
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Re: alternator question
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Rob - https://www.instagram.com/hart_rod_c10 As Iron Sharpens Iron, So One Man Sharpens Another. Proverbs 27:17 FOR SALE: DBW pedal bracket - http://67-72chevytrucks.com/vboard/s...d.php?t=651123 FOR SALE: Hood Brackets http://67-72chevytrucks.com/vboard/s...d.php?t=679945 1987 Silverado SWB - 34.5K original miles http://67-72chevytrucks.com/vboard/s...d.php?t=801834 1969 SuperBurb - http://67-72chevytrucks.com/vboard/s...d.php?t=200387 1968 Farm truck - http://67-72chevytrucks.com/vboard/s...d.php?t=358692 1968 SWB - http://67-72chevytrucks.com/vboard/s...d.php?t=551258 1948 Chevy - http://67-72chevytrucks.com/vboard/s...=122164&page=3 |
12-17-2013, 10:59 PM | #25 |
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Re: alternator question
I am going to rewire mine, 2001 avalanche setup. It just barely puts out 13.5to 13.8. My truck has a factory voltmeter and the charging turn on comes from it (brown wire) I wonder if it has the correct resistance. Jay
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