I can't get winALDL or TunerPro to see my ECM. I get no sensor data or ANY indication that I am connected at all.

I have a GM harness, all sensors, relays, TB, and distributor attached.

ECM: 1227747 (I have three factory chips - ASDU, AKMH, and ABHP).

Upon initialization I get a SES blink and it goes to solid. If I jumper ALDL A & B, it spits back a 12 code. I have a second 1227747, and I have tried swapping chips and ECMs, and the results are the same. This suggests that the chips and ECMs are good.

I have 2 home-rolled ALDL cables (one transistor and the two transistor ALDLcable.com style). The single transistor cable gets attached to A8 and ground. The double get A8, ground, and 12v.

Both cables are recognized in TunerPro. Both cables pass the ALDLTEST v.200 test program from Moates. This suggests that I have the correct COM port and the cables are good.

I have played with the baud rate in winALDL - nothing.

I have checked every lead from the ECM, and they all check out with the "key-on" values (except the EGR control, but I am not too worried since there is no sensor hooked up to that as of yet - or ever perhaps). A8 is in a constant state of flux between 3.5v and 4.0v. With the ALDL cable connected, it is a steady 0.3v.

I am about to scream!!!!

Ok...I just screamed, but it didn't solve anything...

 

What .ads file are you using?

 

winALDL does not require the use of an .ads file.

I am using the 1227747_42.ads for TunerPro.

 

A8's the correct pin, right? I know on the ALDL port itself it's either E or M.

Shows to be correct according to Ludis' reference.

The single transistor unit should be fine for the 160 baud.

Maybe post a brief schematic, and probe voltages at various points in the circuit. Post the results and we can have a look. Could be something simple.

Also, at these data rates, you might be able to use your sound card input as an oscilloscope if you want to check that out.

Try using Hyperterminal at 2400 and 4800, see if it is seeing any activity from the port. Something should pop up with the ECU powered.

Good chatting with you this morning, hope it all works out.

 

Here is what I get:




I am unable to see anything in hyperterminal. I fiddled with various baud rates to no avail.

 

Found the problem! Bad ALDL cable. My soldering was not too hot.

The crappy thing is that both TunerPro and ALDLTEST said the cable was good. It wasn't.

So, don't always believe what the tests say. It may save you a dozen or so hours troubleshooting...