Hello everyone. I am having an electrical issue. I've done some testing with my meter. But it occurred to me that if the ECU is not getting a signal/input, it will not "command" to its corresponding pin location in the computer. Do we have an "ECM guy" on the board? Someone that can "bench test" a computer? Not just check resistors and diodes, but actually apply 12 volts and a ground to verify if power is applied to say pin "A," does it infact go to its corresponding "output pin" 'B" location according to "line diagram" that I have seen on this site. I don't even know if this is possible. But if it were, one could "test" any function the computer commands, [without] being in the car. Thanks very much.
Oem 1227148 ECU.
- Thread starter brandnu6
- Start date
- Joined
- May 28, 2001
Start with the orange ecm wire at the battery.
Here's a link for info.
Bob Bailey may be able to help, too.
Here's a link for info.
Bob Bailey may be able to help, too.
Hi,
there is no direct relationship from input to output, so you can't "static test" the ecm like that. There is a factory test mode that will exercise the I/O, but I don't have any real info about it.
What 'electrical issue" are you having?
Bob
there is no direct relationship from input to output, so you can't "static test" the ecm like that. There is a factory test mode that will exercise the I/O, but I don't have any real info about it.
What 'electrical issue" are you having?
Bob
Hello Bob. Thanks for getting back to me. I wrote a post under " Transmission Talk" last week. Basically, I had my trans rebuilt last year. Someone local. He was highly recommended, so I took a chance. However, once I put it back in the car, I realized "torque converter" wasn't locking up. I checked all of the obvious things, TCC solenoid, replaced "brake switch" the one with purple wire [ACDelco.] Checked voltage at 4-pin connector at transmission, checked voltage at "ALDL'" checked voltage at ECM and also checked all the grounds there are 5. I read somewhere, that if you "jump-out" A&F at "ALDL," ECM ground & and return from TCC solenoid [tan/wht.] wire, it may just work. Well, it did! But that does not solve the problem. I also read that there are two "pressure switches" for 3rd & 4th gear signal/input. All three are "N/C, so I should be able to "read through." Today, at the "ECU" connectors with "key on" I checked "A7" TCC return/signal, to ground and got 11.70v. 1 volt less than "battery voltage." Tomorow, I am going to ring-out C7 & C8 which are 3rd & 4th gear inputs, located at "valve body" in trans. They are also N/C switches, so I should be able to "read through" to ground. I also checked for continuity between "ALDL" ports and "ECU" connectors, they were fine. The only "unknown in this equation is the "VSS," which also comes into play, having to signal ECU. when vehicle is above 45-47 MPH. That is why I posted my question with regard to "static testing" as you put it, were even possible. Otherwise, how does one "test" and verify the status of an ECU? Is it only accomplished by actually swapping out in a car and driving around? P.S. Torque Converter is brand new, Dave Husek 3021. So, Bob. If jumping out "A" and "F" at "ALDL" commands "Lock-Up," what would your conclusion as to what the issue is? Sorry to be so long winded, I'm Trying to avoid dropping tranny pan, But I will if I have to. I also read there is a "Diode in "clutch solenoid," so polarity is crucial. Thanks, Phil
if jumping the aldl will lock the tcc, then the trans is likely fine.
The ECM (presuming its not faulty) decides to lock the TCC based on VSS, TPS, and the gear switches.
We need to read the ALDL data to verify the TPS, gear switches and VSS.
What chip are you running, and is your car digital dash or analog?
Bob
The ECM (presuming its not faulty) decides to lock the TCC based on VSS, TPS, and the gear switches.
We need to read the ALDL data to verify the TPS, gear switches and VSS.
What chip are you running, and is your car digital dash or analog?
Bob
Hi Bob. It was a busy day. Hope you are well. I have a 93 octane TT chip, no alky. The gauges/dash is analog. How does one "read" ALDL data? I do have an old school "OTC 2000" scanner. I do not have a power logger.
Thanks Bob. Thanks for taking the time to help me. By the way, I have another ECU. It's a #1227148, what I didn't realize is that it has '86 Olds. written on it. Question, if I put my chip in it, would it learn and command like the one in the car now? That would be one less thing to consider during this trouble shooting phase. It's a "GM remanufactured" unit, in a GM box. So, it should be ready to go! It's getting late. I will talk to you later. Be safe...
Hi Bob. Thanks again. You're a good man. Take care...
Hi Bob. After changing out ECU with new T.T. chip, clutch locks up
. Must have been when motor spun a couple of rod bearings. Engine "overheated." I say that because the first time tried starting car, it wouldn't fire up. Come to find out the "ignition module" got fried, go figure. Apparently, the electronics in the car reacted. Thank you again for your time. Also, a shout out to Chuck for suggesting that you might be able to help. Anytime I have a problem, this is where I come.
. Must have been when motor spun a couple of rod bearings. Engine "overheated." I say that because the first time tried starting car, it wouldn't fire up. Come to find out the "ignition module" got fried, go figure. Apparently, the electronics in the car reacted. Thank you again for your time. Also, a shout out to Chuck for suggesting that you might be able to help. Anytime I have a problem, this is where I come.
