Communication Timing errors?

I have a 1995 Pontiac Sunfire with a 2.2-liter Vin code 4 Engine with an OBD1 PCM but an OBD2 interface connector.

I have a cable that has pins on one end (to connect to any interface connector) and a UBS connector, which connects with a laptop PC. An ALDL 8192 Baud DataStream is on pin 9 of the Data Link Connector.

A Windows XP Driver connects the USB interface as a Virtual Com port on Com 5.

The problem is that I don’t know which Vehicle file to use. So far, I’ve used LL0.xml and 1995 Pontiac Vin K.xml. Both have a Mode $01 frame of $F4, $57, $01, $00, $B4 for (presumably) getting DTCs.

When I click on chatter, I get a bunch of stuff that seems to be OK and a GREEN light on both MAX232 Interface and Chatter. When I try to send the Engine Data and DTC Macro by clicking on the Start ALDL button, I get the following message: (it’s difficult to print exactly what is there so this is an approximation without timelines).

Start Macro: Engine Data and DTC’s: DATADTCS
Error: reply frame checksum failure
Error: No echo received from Max232
Send: $F4, $57, $01, $00, $B4
Error: reply frame checksum failure
Error: No echo received from Max232
Error: reply frame checksum failure
Stop Macro: Engine Data and DTC’s: DATADTCS

I’m only guessing, but it seems that there is a timing problem of some kind since I can cause the MAX232 Interface to cease working if I set T6 to more than 25 ms.

Can anyone please help?

You can highlight and copy/paste the text from the dispaly in EFILive V4.

Also, turn on the menu option View->Serial IO. Then do the following:

1. Clear the text display. (Right click and select Clear).
2. Select menu: Aldl->Automatically detect chatter.
3. Select menu: Aldl->Display chatter. (and stop it after about 2-3 seconds if it does not stop automatically.).

Then Select all the text (Right click and select Copy all)
and paste the text into an email and email it to paul@efilive.com

Regards
Paul

Thanks for the reply!

I'm puzzled about whether to tick the MAX232 echo on the Comm setup. I don't have a MAX232 circuit but only a cable with loose pins (2) on one end and a USB connector on the other end which connects to the laptop. The pins connect to Pin 9 (datastream) and Pin 5 (ground) of an OBD2 connector.

When MAX232 Echo is selected while detecting chatter, the MAX232 interface light is "green" and says that the interface is OK. When echo is not selected, the light is "green" and says the interface is "assumed" to be OK.

In recording the serial IO, which Echo selection should I use?

Best Regards

The Max232 echo mode indicates to the EFILive software that any commands sent to the interface will be echoed back again. RS232 serial circuits built using the max232 chip will echo back all commands sent to from the PC to the vehicle. The EFILive software needs to know whether or not to read anddiscard those echoed bytes.

If your USB cable does not echo the transmitted data back to the PC then uncheck the Max232 echo check box.

Regards
Paul