Quick Scan Tool CD file help???

vrg3 · Post by **vrg3** » Thu Dec 30, 2004 2:06 am

Yeah, I unfortunately don't have a good sequence of troubleshooting steps for this. Technically the scan tool is using the parallel port in a way it was never supposed to be used, so it's kind of weird.

Does the scan tool correctly identify the parallel port address? It's usually 378 on most computers.

skid542 · Post by **skid542** » Thu Dec 30, 2004 10:16 pm

Okay, I went out and started my car up. While it's sitting there running I hooked up the parallel port and booted up my computer. Program loaded as usual, I hit a key to continue and once again it just sat there. Here is what it said -

Parallel Port at 03bc
Reading ROM ID...

Before I go in and start pulling stuff out, my Haynes manual says (I know... ) that I need to pull my glove box out to get to my ECU (which they are calling ECM). Do I need to pull out the glove box or can I just carefully work back the carpet?

Thanks as always.

vrg3 · Post by **vrg3** » Thu Dec 30, 2004 10:24 pm

Can you check in your laptop's BIOS setup (the one you reach by pressing F1 or F2 or whatever before it boots up) to make sure that 3BC is the correct address of your parallel port? 378 is more common than 3BC.

The Haynes manual's all wrong. The ECU in our cars is under the driver side dash, not on the passenger side. You remove the panel right above the driver's knees and then it's behind a steel brace on the left, with four yellow harness connectors. Do a little searching and I think you can find a picture Josh took of his that shows it nicely.

What do you expect to find when you look at the ECU though?

skid542 · Post by **skid542** » Thu Dec 30, 2004 10:50 pm

Parallel port - Enabled
Mode - Bi-directional
Base I/O address - 3BC
Interrupt - IRQ 7

I was going to look at the ECU just to make it is not some kind of weird nonstandard unit.

vrg3 · Post by **vrg3** » Thu Dec 30, 2004 11:05 pm

Just for the heck of it, try changing the port address to 378.

skid542 · Post by **skid542** » Fri Dec 31, 2004 12:34 am

I tried changing it to 378 and the third option 27? , neither worked. I'm wondering if maybe there is a wire fault somewhere between the wires at the connector (which I'm using my own three wire, polarized connector soldered directly to the car wires) and the ECU? Are there any nominal voltages or anything that I should be reading at the pins. I have a decent meter but it's digital and I'm not sure what the frequency response of it is.

vrg3 · Post by **vrg3** » Fri Dec 31, 2004 2:43 am

Yeah, I didn't really expect changing the port address to solve things.

Try disconnecting the ECU's connectors and connecting the scantool cable to the car but not to your laptop. Then grab a continuity tester. You should measure continuity from pin 1 of the male DB-25 connector to pin 7 of the 16-pin ECU connector. You should also measure continuity from pin 13 of the DB-25 to pin 8 of the 16-pin ECU connector. Finally, you should measure continuity between pin 25 of the DB-25 and the car's chassis. I think I have that right.

Also, none of those should show continuity to each other.

(Reference to the ECU's pins: http://www.graphics.cornell.edu/~v/ecupins/)

skid542 · Post by **skid542** » Fri Jan 07, 2005 11:33 pm

Well I have correct continuity between the ECU and the DB-25 connector. However, I have 103k Ohms between pin 1 on the DB-25 connector and ground when I have the cable plugged in. Car seems to run fine and all, hesitates a couple small RPM bands during a hard acceleration. I think an ECU reset will fix this (did once before a fair while back). Any ideas?

vrg3 · Post by **vrg3** » Sun Jan 09, 2005 8:21 pm

Oh yeah, I forgot about the pull-down resistor. The 103K from pin 1 to ground is correct.

Hm. I'm stumped. Any chance you could try it with a borrowed laptop or something?

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Quick Scan Tool CD file help???