Goose35

I've got a 95 SE with 106K miles. Recently I received the following ECU codes.

0104 vehicle speed sensor.
0304 Knock sensor.
0504 AT control unit or circuit fault.
0302 EGR insufficient or excessive flow detected.

My car is running rough at an idle, more noticeable when the car is in Drive than when in Park. The symptoms seem very similar to when I had a fuel injector go bad.

My questions are,
1. My speedometer is still functioning correctly, so can I assume my vehicle speed sensor is ok?
2. Where is the TCU (transmission control unit) located? I want to check the wiring between it and the ECU. From what I've read, this is one of the possible causes of 0504. Thanks DBM!
3. Bad battery is also a possible cause of 0504. Where is the power connection for the TCU? Is it one of the additional wires on the main Pos + cable connection to the battery?
4. How serious is 0302? The EGR's main purpose is to lower combustion temps to prevent NOx from forming. Can this lead to damage of the 02 sensors and/or catalytic convertor?

I'm not so much worried about the knock sensor 0304. My car is running rough and I not surprised it set 0304.

Thanks in advance for your help/advice.
-Pat

iwannabmw

iTrader: (3)

About the 0302 code. After adjustin my idle down after cleaning my TB, I got the 0302 code. After getting tired of lookingat it, I adjust the idle up to about 700 rpm (on a 5 speed), reset the ECU and haven't seen the code again. My bet is that the rough/low idle is setting off the "insufficient flow" part of the code. If you fix whatever idle issue you have, I think the code will be taken care of.

Miasma

how do you adjust the idle?

iwannabmw

iTrader: (3)

After the car is fully warmed up. Shut it off and disconnect the TPS. That's the brown connector near the IACV. Start the car, it will idle funny. Rev it a few times and let it settle down. There is a large black screw pointing straight down near the throttle body. Adjust that left to raise the idle. When you're done adjusting it, stop the car and re-connect the TPS. Start the car and rev it a few times and see where the idle falls. All fans, including and the auxilliary one should be off and there should be no electrical load on the car. These instructions are kinda basic, but you can probably figure it out by looking at the car for a little while to see what I mean. If you have a manual or someone already posted pics about this you should be all set. A search might reveal more detailed info.