Checksum error 4000 during read

[5.3buggy]

I've got a 2002 5.3 harness and computer that I am reworking. I'm bench checking everything and with this unit I keep getting this same error while trying to read it. It fails at 3% everytime.

"VCM read failed at loc: 4000 error: checksum"

I've tested my bench setup on my personal harness and computer and I can read it evertime. The problem computer is from a wrecking yard, out of a 2002 suburban, don't think anyone has done any programming on it.

Any ideas? Thanks in advance.

[Keith@HPTuners]

It may have been programmed by a handheld. We've seen that error before when they are programmed by handhelds.

[5.3buggy]

Recommendations? Have it flashed by a TECH2?

[Keith@HPTuners]

Yea, that should fix it.

[5.3buggy]

Thanks Keith. Is it possible to do the same thing with a bin file from this site and have it flash entire? I realize it would cost credits to do this.

[Keith@HPTuners]

That should fix it as well.. however, I cannot gaurantee that.

I fixed a few of these years ago in person (due to handhelds) and I recall flashing them entire with a known good file..

I tell you what.. Take a VCM Suite info log of the vehicle now, post it here (remove your serial # and key).. and try a write entire with a known good file. You will have to license that file (unless you already have a license for it) and the ECM (which you currently cannot read)... If it still throws the error (which it shouldn't), I'll throw you two free credits..

[5.3buggy]

I tried uploading it to here but I'm not having any luck. I put it on my site and you can see it here.


Suite Info Link

[5.3buggy]

This fixed it. Thanks for the help Keith.

[Bill@HPTuners]

so just doing the write entire worked fine? Did it use 2 or 4 credits?

[5.3buggy]

Correct entire write fixed it, took 4 credits.

[Pur_SSyn]

I'm receiving the same error on a car I have previously scanned.

It has not been programmed since, however we suspect the computer may
be damaged from an arc weld in which 600 Volts was applied to the frame.

The car also has a weak battery and is now charging for the night. This
may also be an issue as sometimes the "Preparing VCM" would also fail.

My concern and question is:

If the computer is damaged, would I be able to read some of the parameters
as shown in the screen shot?

[EC_Tune]

If the battery was low that will throw bootloader errors and other timeouts. The battery has to be at a minimum voltage (reported in the status bar when you read or write) to work successfully.

[Pur_SSyn]

Good to know and fits one of the symptoms.

Thanks and I'll let you know what I find tonight!

[Pur_SSyn]

No go with the new battery.

The VCM Scanner read 12.4 VDC while reading the Entire VCM.

I'm still getting the Checksum Error 4000

This car was previously scanned by me and I have the file on my laptop.
It was not programmed by another device since downloading the file.

The car did not leave my side, and I can only conclude that the arc welder
smoked the computer and/or some vehicle sensors.

I'm going to try uploading the tune in hopes that any bad cells will get overwritten.

Failing that, I'll have to start troubleshooting the electrical.

If anyone could help out with any of the polled sensors that the
computer requires to start the car, I would really appreciate it.

I'm thinking it's possible that a sensor was damaged and the computer
requires a response from certain sensors in order to start the motor.

If Checksum Error 4000 points to a range of cells, or sensors that I
should be testing, please list them.

Thank you in advance...like never before!

[EC_Tune]

If you have the original file, try a Write Entire. There is risk involved but it may resurrect your PCM.