1. Home
  2. General Motors Forum
  3. to all concerned: CarBytes V2 program bug

to all concerned: CarBytes V2 program bug

Warning:

There is a bug in the CarBytes V2 program. The program will incorrectly display MALF flags. The author of this freeware program (Paul Blackmore) has been contacted. He has researched the problem and has kindly offered a workaround. I am publishing this info here for the benefit of the users of this very useful program.

The following is the email correspondence on this subject.

------------------------------------------------------------------------ Hi Bill,

I have spent some time investigating the problem that you raised. The solution is to specify the start byte/bit position of a Malf data type as 1 rather than 1.0 I have not checked but I am almost 100% certain that the same can be said for "Flag" data types as well.

Explanation Internally, CarBytes identifies each bit of a Malf data type using the "byte.bit" notation. Each Malf byte is evaluated 8 times, once per bit and each time, the bit number is appended to the starting byte.

If the starting byte is specified as 1.0 then the following incorrect byte.bit identifiers are used:

1.0.0 1.0.1 1.0.2 1.0.3 1.0.4 1.0.5 1.0.6 1.0.7 This results in the first bit (1.0) being evaluated for ALL bit positions in the Malf byte. This behaviour can be observed by changing the first byte in TEST.alg from $12 to $13.

If the start byte is specified as 1 then the following incorrect byte.bit identifiers are used:

1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Which will correctly evaluate each seperate bit of the Malf byte.

It is a bug, but because the "work-around" is trivial, no patch will be created. I appreciate the legwork you have already done to help track down this problem, and thankyou for sending the test files.

Regards Paul Blackmore

> -----Original Message----- > *From:* Bill [mailto:.........] > *Sent:* Sunday, 30 November 2003 6:37 AM > *To:* snipped-for-privacy@starrperformance.com.au > *Subject:* CarBytes > > Gentlemen, > > I downloaded the CarBytesV2 program. There is a bug in the mapping of > MALF bytes. Regardless of which byte in the data stream is referenced > the results always show the green check mark. I attached two files, to > demonstrate the problem. The first byte of the stream is $12 therefore > bits (00010010) but none of the MALF's are flagged. > > Please advise. > > Yours, > Bill

snipped-for-privacy@gflocfk.net remove all "f"'s from address

Reply to
Bill
Loading thread data ...

Crap, there is still one kludge to get MALF display to work right. You have to enter the MALF flag info in reverse order int eh ALDL Editor. Example:

In order to define byte 58 which is

58 ACTMLF01 ACTIVE MALFUNCTION FLAG WORD 1 0 ACTIVE CODE 123 THROTTLE POSITION HIGH 1 ACTIVE CODE 629 INVALID PASS KEY FREQUENCY 2 ACTIVE CODE 341 INTERMITTENT CAM SIGNAL 3 ACTIVE CODE 321 18X INTERRUPTS LOST 4 ACTIVE CODE 630 BATTERY VOLTAGE OUT OF RANGE 5 ACTIVE CODE 117 COOLANT SENSOR LOW 6 ACTIVE CODE 118 COOLANT SENSOR HIGH 7 ACTIVE CODE 134 ENGINE 02 SENSOR NOT ACTIVE

You have to define it in CarBytes as

58 ACTMLF01 ACTIVE MALFUNCTION FLAG WORD 1 7 ACTIVE CODE 123 THROTTLE POSITION HIGH 6 ACTIVE CODE 629 INVALID PASS KEY FREQUENCY 5 ACTIVE CODE 341 INTERMITTENT CAM SIGNAL 4 ACTIVE CODE 321 18X INTERRUPTS LOST 3 ACTIVE CODE 630 BATTERY VOLTAGE OUT OF RANGE 2 ACTIVE CODE 117 COOLANT SENSOR LOW 1 ACTIVE CODE 118 COOLANT SENSOR HIGH 0 ACTIVE CODE 134 ENGINE 02 SENSOR NOT ACTIVE

This is the only way CarBytes will properly display MALF error codes.

Good luck to all.

snipped-for-privacy@gflocfk.net remove all "f"'s from address

Reply to
Bill

Crap is right, now I have to redo my definition files. For some reason I saw this coming, but wouldn't have noticed until my MIL came on and spent a couple of hours diagnosing and replacing the wrong part.

Steve

Reply to
Steve Mackie

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.