reset blm's ~ connect positive terminal to negative terminal?
09-26-2011, 08:17 PM
#1
Burning Brakes
Thread Starter
reset blm's ~ connect positive terminal to negative terminal?
so I was talking to the guy's at AEM... about tuning my engine and he said when you pull the chip you can make sure the capacitors/blm's are for sure reset by touching the positive terminal to the negative terminal? yea?
09-26-2011, 08:29 PM
#3
Burning Brakes
Thread Starter
91 corvette. the ECM/pcm's blm's... when you pull the battery cable and pull the prom... not always do all the stored blm's reset back to 128 in all the cells.
sometimes they will remember their stored numbers...
heard you could pull the fuse, but I tried that. that didn't work either.
sometimes they will remember their stored numbers...
heard you could pull the fuse, but I tried that. that didn't work either.
09-26-2011, 08:35 PM
#5
Burning Brakes
Thread Starter
09-26-2011, 08:35 PM
#6
Burning Brakes
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09-26-2011, 08:40 PM
#7
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Yes, if you disconnect the negative or positive (preferably negative) terminal from your battery and touch it to the opposite terminal, you will rapidly discharge the ECM's capacitors rather then waiting approx 20 minutes for them to discharge to remove power from the ECM's RAM memory that stores the BLM's learned value, to reset them to their default value, 128.
09-27-2011, 03:37 AM
#8
Burning Brakes
Thread Starter
Yes, if you disconnect the negative or positive (preferably negative) terminal from your battery and touch it to the opposite terminal, you will rapidly discharge the ECM's capacitors rather then waiting approx 20 minutes for them to discharge to remove power from the ECM's RAM memory that stores the BLM's learned value, to reset them to their default value, 128.
walk me through this... it's been a long time since physics class.
if i disconnect the negative terminal which is the push side (current flows from negative to positive) of the current.... I can touch that negative cable to the positive terminal and it will release the stored energy by grounding it out in the positive terminal, right?
which terminal is normally called "the ground"?
09-27-2011, 03:57 AM
#9
so car batteries...
walk me through this... it's been a long time since physics class.
if i disconnect the negative terminal which is the push side (current flows from negative to positive) of the current.... I can touch that negative cable to the positive terminal and it will release the stored energy by grounding it out in the positive terminal, right?
which terminal is normally called "the ground"?
walk me through this... it's been a long time since physics class.
if i disconnect the negative terminal which is the push side (current flows from negative to positive) of the current.... I can touch that negative cable to the positive terminal and it will release the stored energy by grounding it out in the positive terminal, right?
which terminal is normally called "the ground"?
Connected to chassis & the engine block ground.
Usually has a " - " Minus symbol next to it.
Don't get silly & dead short out the battery itself.
Enough current to heat up a Snap On wrench or ratchet to glowing red hot in 2 seconds.
Over 2,000 amps present when you dead short out an automotive group 75 battery like in our C4's.
Large truck batteries hooked in parallel of 3's or 4.........over 10,000 amps of current present when dead shorted.
Electrical Fireworks occur immediate.
Your hand will catch on fire with than metallic tool if not careful.
Brian
09-27-2011, 07:43 PM
#12
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Once you have disconnected the battery ground cable, I don't see how touching it to the positive terminal is more dangerous then walking to and from the passenger compartment to turn on the headlight switch. If you are concerned about safely touching the negative cable to the positive cable, you should not drive, it is much more dangerous.
09-27-2011, 07:48 PM
#13
Burning Brakes
Thread Starter
Once you have disconnected the battery ground cable, I don't see how touching it to the positive terminal is more dangerous then walking to and from the passenger compartment to turn on the headlight switch. If you are concerned about safely touching the negative cable to the positive cable, you should not drive, it is much more dangerous.
09-28-2011, 03:06 AM
#14
Race Director
You don't have to go through any of the agonizing processes described above.
GM very cleverly put a connector right next to the positive battery terminal that goes directly to the ECM through a fusible link. Disconnect that connector for a few seconds and your ECM will be reset. No tools are required. This connector is shown in Figure 4 on page 6E-6 of the FSM.
Resetting the ECM will clear all the historic error codes and reset the BLMs to their default value, which is 120.
GM very cleverly put a connector right next to the positive battery terminal that goes directly to the ECM through a fusible link. Disconnect that connector for a few seconds and your ECM will be reset. No tools are required. This connector is shown in Figure 4 on page 6E-6 of the FSM.
Resetting the ECM will clear all the historic error codes and reset the BLMs to their default value, which is 120.
09-28-2011, 04:31 PM
#17
Race Director
You don't have to go through any of the agonizing processes described above.
GM very cleverly put a connector right next to the positive battery terminal that goes directly to the ECM through a fusible link. Disconnect that connector for a few seconds and your ECM will be reset. No tools are required. This connector is shown in Figure 4 on page 6E-6 of the FSM.
Resetting the ECM will clear all the historic error codes and reset the BLMs to their default value, which is 120.
GM very cleverly put a connector right next to the positive battery terminal that goes directly to the ECM through a fusible link. Disconnect that connector for a few seconds and your ECM will be reset. No tools are required. This connector is shown in Figure 4 on page 6E-6 of the FSM.
Resetting the ECM will clear all the historic error codes and reset the BLMs to their default value, which is 120.
09-28-2011, 05:19 PM
#18
Burning Brakes
Thread Starter
09-28-2011, 05:27 PM
#19
Burning Brakes
Thread Starter
You don't have to go through any of the agonizing processes described above.
GM very cleverly put a connector right next to the positive battery terminal that goes directly to the ECM through a fusible link. Disconnect that connector for a few seconds and your ECM will be reset. No tools are required. This connector is shown in Figure 4 on page 6E-6 of the FSM.
Resetting the ECM will clear all the historic error codes and reset the BLMs to their default value, which is 120.
GM very cleverly put a connector right next to the positive battery terminal that goes directly to the ECM through a fusible link. Disconnect that connector for a few seconds and your ECM will be reset. No tools are required. This connector is shown in Figure 4 on page 6E-6 of the FSM.
Resetting the ECM will clear all the historic error codes and reset the BLMs to their default value, which is 120.
I see that page it references a positiver battery terminal pigtail, the inline fuse holder that originates at teh positive connection at the battery, or the ECM fuse in the fuse block. it says power must be disconnected for at least 30 seconds to clear the codes.
well the ecm fuse didn't work for me.... neither does pulling that battery cable which it says also works....
10-03-2011, 03:54 AM
#20
Race Director
That's the connector you need to open to reset the ECM. It clears the history error codes and resets all the BLMs to their default value of 120. You don't need to disconnect it for 30 seconds. It only takes a couple of seconds (I measured it). Just unplug it and then plug it back in.
Part of the problem is that the ECM fuse isn't really an ECM fuse. It's in the ignition circuit between the ignition switch and the ECM. It doesn't reset the error codes.
The handy little ECM connector by the positive battery terminal is in series with a fusible link and goes directly to the ECM. It absolutely amazes me how few people know about this connector, even after all these years. I am on a personal crusade to educate the folks on the forum about it. On my to-do list is to get a pic so I can post it in the future.
Part of the problem is that the ECM fuse isn't really an ECM fuse. It's in the ignition circuit between the ignition switch and the ECM. It doesn't reset the error codes.
The handy little ECM connector by the positive battery terminal is in series with a fusible link and goes directly to the ECM. It absolutely amazes me how few people know about this connector, even after all these years. I am on a personal crusade to educate the folks on the forum about it. On my to-do list is to get a pic so I can post it in the future.
