PCM write problems, cabling ?

They go by many names, P01, P59, VPW, '0411 etc . Circa 1999 to 2006. All VPW OBD2 PCMs.
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PCM write problems, cabling ?

Postby joukoy » Fri Aug 07, 2020 4:22 am

Hello.

I have P59 in old vehicle (no other devices in bus). Using Obdlink LX.
First time I wrote calibration with Pcmhammer 14, I get zero errors.
Next time there was couple of "BUS BUSY" messages, but write was succesful. After that, every time more and more errors.

Then write failed every time when fuel pump started shortly during kernel upload, and write was succesful only after removing fuel pump fuse.
Now I can write calibration only if I remove green connector from PCM.

Any ideas, where I should start looking for solution?

Example of BUS BUSY messages, when writing was still working:
Code: Select all
[08.07.14.472]  OK
[08.07.14.529]  TX: STPX H:6D10F0, R:1, L:1033
[08.07.14.589] 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
[08.07.15.248]  Unexpected response to STPX payload: BUS BUSY
[08.07.15.249]  Unexpected response to STPX payload: BUS BUSY
[08.07.15.273]  WritePayload: Unable to send message.
[08.07.15.325]  TX: STPX H:6D10F0, R:1, L:1033
[08.07.15.383] 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
[08.07.16.449]  RX: 6D F0 10 76 00
[08.07.16.450]  Found response, Success

Posts: 698
Joined: Sat Dec 15, 2018 7:38 am

Re: PCM write problems, cabling ?

Postby Gampy » Fri Aug 07, 2020 5:43 am

Please try the following,

Disconnect the tool from both the car and PC.
Disconnect the PCM from all power.

Let them set while you check the battery voltage and top it off if need be ... 12.5v or greater! (preferably greater)
Verify your wiring isn't around any power cables.

Power the PCM
Wait 15s
Hook up to car
Hook up to PC
Wait 15s
Open PcmHammer and do a Test Write.

Please post a full debug log of the one attempt.
Temporary is a permanent problem!

Posts: 203
Joined: Sun Apr 10, 2016 9:20 pm

Re: PCM write problems, cabling ?

Postby kur4o » Sat Aug 08, 2020 2:38 pm

To rule out any wiring in-car issues. Try a bench flash. You can also try lsdroid if the cable has bluettoth. That will rule out any pc-cable-hammer issues.

That fuel pump on is not normal behavior. When it start running, Can the voltage drop for a split second when it is turned on. Running pump indicates that the pcm is out of flash state.

Definitely something is not good there. I would stay with cal flash only till you get stable enough communication. At least that will save you from bricking.

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Re: PCM write problems, cabling ?

Postby joukoy » Sat Aug 08, 2020 3:42 pm

Found it:
Unplugged alternator wiring, now test-write works fine. No more fuel pump starting during kernel upload.

I will disconnect PCM from alternator and use old good alt warning light.

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Re: PCM write problems, cabling ?

Postby Gampy » Sat Aug 08, 2020 6:10 pm

Thank you for letting us know!

-Enjoy
Temporary is a permanent problem!

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Re: PCM write problems, cabling ?

Postby joukoy » Sat Aug 08, 2020 7:31 pm

joukoy wrote:Found it:
Unplugged alternator wiring, now test-write works fine. No more fuel pump starting during kernel upload.

I will disconnect PCM from alternator and use old good alt warning light.


No :evil:
PCM is not connected to alternator now, still looks like pcm is resetting (?) when uploading kernel.
But not if alternator is unplugged :?:

Probably it is voltage drop problem, I need to check my PCM power supply connections & wirings.
Attachments
pcmwrite-failure-2020-08-08-2.txt
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Re: PCM write problems, cabling ?

Postby joukoy » Sun Aug 09, 2020 6:28 pm

Didn't found any problems from +12v cables, but soldered all connectors.
Cleaned & tightened ground connections and added extra ground cables:
- Battery to body
- PCM pin 60 to body (was already to engine but long cable)

At least 3 test writes without any problems :thumbup:

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Re: PCM write problems, cabling ?

Postby joukoy » Mon Aug 17, 2020 2:03 am

joukoy wrote:Didn't found any problems from +12v cables, but soldered all connectors.
Cleaned & tightened ground connections and added extra ground cables:
- Battery to body
- PCM pin 60 to body (was already to engine but long cable)

At least 3 test writes without any problems :thumbup:


Today tested calibration write first time after adding cables, and it failed again.
Unplugged alternator and write was succesful.

:wall:

I give up for now.

Posts: 203
Joined: Sun Apr 10, 2016 9:20 pm

Re: PCM write problems, cabling ?

Postby kur4o » Mon Aug 17, 2020 4:29 am

You might have bad voltage regulator, or wrong type of alternator. It can produce too much noise to the pcm. It is known that vpp voltage can freak out the processor if on all the time.

Testing with another alternator can pinpoint the problem.

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Re: PCM write problems, cabling ?

Postby joukoy » Fri Aug 21, 2020 5:18 am

Removed wire from alternator Sense-pin to B+, after this 3 succesful calibration writes, with one BUS BUSY message.

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