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98 Lumina PCM Flash???


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Hymer
User

May 31, 2010, 8:28 PM

Post #1 of 28 (4622 views)
98 Lumina PCM Flash??? Sign In

Hi, everyone, I've got a stumper. I replaced a PCM in the above car 3.8L (vin K) engine due to a low voltage reading on the fuel pump control wire on the original PCM. Now I cannot get the car to fire (more than 1 time) I have Fuel pressure of 45-55 at crank, I have spark, I seem to have my square waves at the 3x an 18x ign cont module [both crank sensors] and at the PCM. I don't seem to have any injector pulse.
I also have from what I can tell NO security issues, but it acts like it needs a key re-learn. When I put the old PCM in the car runs, [but still has the fuel pump issue] so I know its nothing else that is causing this. The PCM was used but has the same hardware AND service numbers as the original. Do I need a flash, do a crank variation learn [with a tech II] or do I have a junk PCM? I'm stumped!

Thanks !!


Sidom
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May 31, 2010, 10:33 PM

Post #2 of 28 (4618 views)
Re: 98 Lumina PCM Flash??? Sign In

How ya doin Hymer

While a brand new PCM does need to be reflashed I have seen used ones with the same service #s work....Still not a bad idea to reflash but they start and it wouldn't be a bad idea to do the crank relearn.

Pull codes from the PCM and see if there is any anti-theft codes and just for the heck of it, do the 10 minute relearn.

Just out of curiosity, what exact problem were you having with the car & what did you find on circuit 465?


Hymer
User

Jun 1, 2010, 5:05 AM

Post #3 of 28 (4610 views)
Re: 98 Lumina PCM Flash??? Sign In

I was only getting 5 volts on the fuel pump relay, chased it down right to the output off the pcm. This would let the car start, but it wouldn't restart unless you pulled the relay. Chased grounds for a while but found nothing. fuel pump wouldn't prime either, it just ran all the time. New PCM does what it's supposed to just wont start. and I have no codes in either PCM. any other ideas? I'm open for about anything!


Hammer Time
Ultimate Carjunky / Moderator
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Jun 1, 2010, 1:47 PM

Post #4 of 28 (4607 views)
Re: 98 Lumina PCM Flash??? Sign In

You probably need to do a security relearn


Disconnect the battery and hold the cables together for about 30 seconds then reconnect the cables before performing the procedure.Read it carefully if done incorrectly it won't work.If it helps let me know.
Turn ON the ignition, with the engine OFF.
Attempt to start the engine, then release the key to ON (vehicle will not start).
Observe the SECURITY telltale, after approximately 10 minutes the telltale will turn OFF.
Turn OFF the ignition, and wait 5 seconds.
Repeat steps 1 through 4 two more times for a total of 3 cycles/30 minutes (the vehicle is now ready to relearn the Passlock™ Sensor Data Code and/or passwords on the next ignition switch transition from OFF to CRANK).
Important
The vehicle learns the Passlock™ Sensor Data Code and/or password on the next ignition switch transition from OFF to CRANK. You must turn the ignition OFF before attempting to start the vehicle.
Start the engine (the vehicle has now learned the Passlock™ Sensor Data Code and/or password).
With a scan tool, clear any DTCs if needed (history DTCs will self clear after 100 ignition cycles).



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Hymer
User

Jun 1, 2010, 6:00 PM

Post #5 of 28 (4600 views)
Re: 98 Lumina PCM Flash??? Sign In

I have tried the re-lear a few times. I'll give it another shot. The security acts perfectly normal when I try to start it with the "new" PCM. But that i guess doesnt mean much. It has the old VATS style key also. I was told by the dealer "Good Luck.." hehe.. I guess I say that to people sometimes too when I don't want to deal with their problems.


Hammer Time
Ultimate Carjunky / Moderator
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Jun 1, 2010, 6:03 PM

Post #6 of 28 (4597 views)
Re: 98 Lumina PCM Flash??? Sign In

If your not getting a flashing security light, it's not likely your problem.



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Hymer
User

Jun 1, 2010, 6:28 PM

Post #7 of 28 (4593 views)
Re: 98 Lumina PCM Flash??? Sign In

Yeah the light seems to do what it is supposed to. goes out after 10 seconds or so. I am doing the re-learn right now, so I guess we will see. I thought the fuel pump would disable if the BCM and PCM didn't talk wo each other. I have run into that before and the relarn did the trick. The fuel pump stays Hot while cranking [after the first fire] and I do have spark, but no injector pulse. Also NO DTCs after the original fire. Mabey he PCM is bad, it was from a yard. Stupid cars.. If ya come up with anything feel free to hollar!

Thanks!


Hammer Time
Ultimate Carjunky / Moderator
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Jun 1, 2010, 6:31 PM

Post #8 of 28 (4590 views)
Re: 98 Lumina PCM Flash??? Sign In

Check for power supply at the injectors and check your fuses real good



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Hymer
User

Jun 1, 2010, 6:58 PM

Post #9 of 28 (4586 views)
Re: 98 Lumina PCM Flash??? Sign In

The relearn did nothing. still cranks and fires once then wont fire again. the fuel injection fuse is good, 12v . When I get 12v on the orange wire on the injector [to ground], then accross the injector plug while cranking I saw 6 volts. hmmmmm I dont think thats correct.. any ideas?


Hammer Time
Ultimate Carjunky / Moderator
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Jun 1, 2010, 7:02 PM

Post #10 of 28 (4582 views)
Re: 98 Lumina PCM Flash??? Sign In

You may have a shorted harness or injector. Try unplugging all of them.



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Hymer
User

Jun 1, 2010, 7:08 PM

Post #11 of 28 (4579 views)
Re: 98 Lumina PCM Flash??? Sign In

Well, I can put the old pcm in and the stupid car starts and runs fine. just doesn't restart! so I know the harness and injectors are fine. its down to the PCM. something just isn't right. cant think of anything to do without having the Tech II hooked to the car.. tray an injector balance and see if the pcm would operate them.. The injectors operate off a ground pulse from the PCM if I'm not mistaken. The 12v side just stays hot while the key is on correct?


Sidom
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Jun 1, 2010, 7:41 PM

Post #12 of 28 (4575 views)
Re: 98 Lumina PCM Flash??? Sign In

With the engine firing up & dying, that reallly sounds like a security issue. With the relearn, you do have to try it 3 times in a row. Check the VTD PID to see if the password is valid. If you have a Tech II you can use that to do the relearn as well......

You are correct on the injectors, they all feed off the same fuse & the PCM grounds them...


Will it run on carb clean?????


Hymer
User

Jun 1, 2010, 7:48 PM

Post #13 of 28 (4574 views)
Re: 98 Lumina PCM Flash??? Sign In

Yeah, it really does seem to act like an anti theft deal, but without a tech II here at the moment I can't tell for sure. lucky to have one at the shop, now the question is how much $$ they want for me to use it! Thanks for the help guys! If you think of anything feel free to let it fly, I'm out of ideas, and will let ya know when I figure it out


Sidom
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Jun 1, 2010, 8:36 PM

Post #14 of 28 (4571 views)
Re: 98 Lumina PCM Flash??? Sign In

Do you have any type of scanner? If I remember correctly you can see the VTD PID on the main data screen.......


Hammer Time
Ultimate Carjunky / Moderator
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Jun 2, 2010, 2:37 AM

Post #15 of 28 (4565 views)
Re: 98 Lumina PCM Flash??? Sign In

It initially starts fine but if shut off, will not restart?????????

Wasn't that a symptom of a cam sensor problem? I remember something like that.



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Hymer
User

Jun 2, 2010, 5:34 AM

Post #16 of 28 (4559 views)
Re: 98 Lumina PCM Flash??? Sign In

No, the original problem was definitly the control ckt on the fuel pump, there was no 2 sec prim, the pump just ran all the time without the car running [because the relay wouldn't pull back] and once started it was fine. but when you shut it off and went to restart, the PCM couldn't provide enough to close the relay, you would have 4 volts on the control wire. I even isolated this with an new external relay, and just used the green/white control wire to turn it on, with a seperate ground and the fuel pump un plugged and got the same results. The new PCM gices me the 2 sec prime etc.. and 12v on my pump control ckt when it is supposed to. As far as a scanner, I have my smaill generic one, that will sometimes pick up BCM codes from GM in adition to any P codes that may pop. but Im pretty limited as far as the data stream goes. I'll try and check it out at the shop today, mabey another lumina will show up and I can play a bit.


Hammer Time
Ultimate Carjunky / Moderator
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Jun 2, 2010, 9:30 AM

Post #17 of 28 (4552 views)
Re: 98 Lumina PCM Flash??? Sign In

That makes sense. It does sound like the computer needs to be flashed. I believe all OBD2 GMs require that.



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Hymer
User

Jun 2, 2010, 9:16 PM

Post #18 of 28 (4541 views)
Re: 98 Lumina PCM Flash??? Sign In

i didn't have much time tonight, but I got a hold of a brick scanner from my snap on guy, pulled a PO1610 PZM to BCM data loss. I had crank signal , cam signal, but NO fuel pulse width data. the VIN # in the PCM and the VIN to the car don't match.. any ideas guys?


Hammer Time
Ultimate Carjunky / Moderator
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Jun 3, 2010, 2:41 AM

Post #19 of 28 (4535 views)
Re: 98 Lumina PCM Flash??? Sign In

That indicates it needs to be flashed. Without the VIN matching, it won't communicate.



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Hymer
User

Jun 3, 2010, 5:26 AM

Post #20 of 28 (4532 views)
Re: 98 Lumina PCM Flash??? Sign In

Thats what I was thinking also. I've never done a flash or seen it done for that matter. I belive you download the program into the tech II then go to the car a shoot that program in. does that sound right?


Hammer Time
Ultimate Carjunky / Moderator
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Jun 3, 2010, 5:29 AM

Post #21 of 28 (4529 views)
Re: 98 Lumina PCM Flash??? Sign In

Yes, something like that but I believe you have to subscribe to the downloads to get them. I also believe you need the attachments for the Tech2 to be able to do it. Your better off to just pay someone to do it. Most of them just charge an hours labor.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Hymer
User

Jun 3, 2010, 7:47 PM

Post #22 of 28 (4520 views)
Re: 98 Lumina PCM Flash??? Sign In

Ok guys, the original PCM had a fuel pump control ckt code in it [woo hoo] I diaged it right without a scanner, but wasted a ton of time. anyhow, the new PCM is out of an olds intrige same engine, hardware and service numbers. BUT it wont work with this lumina, different stuff in the bcm I suppose. I'm gonna try another PCM out of hopefully the same car and see if that works. If not then I found a place that flashes them other than the dealer. Happened to be a guy I used to work with that stopped in the shop today. So 145 bux for a on-site flash I guess is the worse case senario. As for the flash you need a Tech II and have to download it from the subscription site via the VIN number of the car and shoot it into the new PCM. I'll let you know how this turns out. Again thanks for the help everyone you guys are great, and I really appreciate it! I'm sure to have a few more stumpers in the future.. They are kinda fun. I'm really lucky they guy who owns this car is really cool and very patient..


Hammer Time
Ultimate Carjunky / Moderator
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Jun 4, 2010, 2:44 AM

Post #23 of 28 (4512 views)
Re: 98 Lumina PCM Flash??? Sign In

Up until now I hadn't noticed that you were trying to put a used PCM in here but now I find out it's not even from the same car. That's not going to work without programming. The VIN is burned in.



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Hymer
User

Jun 6, 2010, 6:47 PM

Post #24 of 28 (4499 views)
Re: 98 Lumina PCM Flash??? Sign In

The saga continues! Got another PCM, car started right up! However I now am spitting out a P0740 TCC solenoid code. When the key is on I get a buzzing from the tranny [tcc solenoid] I disconnected the harness on the tranny and get 2 volts on it, and with a logic probe I get a red/green flicker. I also get this right off the PCM [brown wire]. pin 78 i belive. Now the question is, will this damage the transmision by running it with this acting up? I am not much of a tranny guy, the car seems to be running and shifting great. I am wondering if I got another bad PCM!


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Jun 6, 2010, 6:49 PM

Post #25 of 28 (4497 views)
Re: 98 Lumina PCM Flash??? Sign In

Is this another used PCM?



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.







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