240 experts

[nismo 240sx]

hey my check engine light is on and it says its a knock sensor and it also says iacv-aac...
is it bad if i drive it around like that. the car runs smooth but iam afraid it will die on me.

[MELLO*SOS]

http://zilvia.net/f/data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABwAAAAOCAYAAAA 8E3wEAAAABmJLR0QA/wD/AP+gvaeTAAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB3RJTUUH1Q UUDyoqJjAqRwAAAN1JREFUOMu1lMkVwyAMBYe0JGpCNUFNVk3k 4AUwxPGS+ILxkzX8jyTH/Sfu9nrmJ3cXlnMASyWRPwd2d5XlHCBZn1BthcbRAdxTZQDI8k3 mQzg11rhF+QZ9jdNOcQib6GFQYJYgCFucSRf6GsLU6wEY5yubT FqF2yq1vRwr3INXdQUWG+je1pELX4ED1wDyRAR0WfuAA9gloIT yvsFMIMgYInYRqF6rO9Sqz9qkO5ilyo0o3YBwJ+6vrdQonxWUQ llhXeHcb/wabMPkP2n81ocAIoLZrMqn/4y2RwP8DcQ+d6rT9ATiAAAAAElFTkSuQmCC

http://zilvia.net/f/data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABwAAAAOCAYAAAA 8E3wEAAAABmJLR0QA/wD/AP+gvaeTAAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB3RJTUUH1Q UUDyoqJjAqRwAAAN1JREFUOMu1lMkVwyAMBYe0JGpCNUFNVk3k 4AUwxPGS+ILxkzX8jyTH/Sfu9nrmJ3cXlnMASyWRPwd2d5XlHCBZn1BthcbRAdxTZQDI8k3 mQzg11rhF+QZ9jdNOcQib6GFQYJYgCFucSRf6GsLU6wEY5yubT FqF2yq1vRwr3INXdQUWG+je1pELX4ED1wDyRAR0WfuAA9gloIT yvsFMIMgYInYRqF6rO9Sqz9qkO5ilyo0o3YBwJ+6vrdQonxWUQ llhXeHcb/wabMPkP2n81ocAIoLZrMqn/4y2RwP8DcQ+d6rT9ATiAAAAAElFTkSuQmCC

The knock sensor (code 34) code is 90% of the time because of a short in your wiring to the knock sensor. Other times, the sensor itself has melted or been destroyed. It will not harm your engine driving like that. However, because that code 34 is stored on your ECU, you will notice your engine produces a lot less power than normal (timing is retarded to prevent knock). To fix the issue you need to find the short in the wiring and splice/solder to repair it (or replace the sensor itself if it's bad). If you search around for "code 34" you will find many posts on the topic, where to look for the short, how to replace the knock sensor, etc. It's a common issue on the KA24DE.

IACV I don't know the solution, you may have a short or the unit itself might be bad/gummed up/etc.

[racepar1]

I don't think the ecu is smart enough to detect a mechanical failure in the iacv (gummed up, etc...). It almost certainly has an electrical problem. Not onlyu that, but I have actually taken an iacv apart and I see no reasonable way that the iacv could get clogged. To start make sure the connection for the sub-harness that goes under the intake mani is clean and stick a pick or small screwdriver in there and crimp down the female pins a bit more. Also make sure the iacv connector itself is actually plugged in, clean and tight.

[Drifterxxl180]

http://zilvia.net/f/data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABwAAAAOCAYAAAA 8E3wEAAAABmJLR0QA/wD/AP+gvaeTAAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB3RJTUUH1Q UUDyoqJjAqRwAAAN1JREFUOMu1lMkVwyAMBYe0JGpCNUFNVk3k 4AUwxPGS+ILxkzX8jyTH/Sfu9nrmJ3cXlnMASyWRPwd2d5XlHCBZn1BthcbRAdxTZQDI8k3 mQzg11rhF+QZ9jdNOcQib6GFQYJYgCFucSRf6GsLU6wEY5yubT FqF2yq1vRwr3INXdQUWG+je1pELX4ED1wDyRAR0WfuAA9gloIT yvsFMIMgYInYRqF6rO9Sqz9qkO5ilyo0o3YBwJ+6vrdQonxWUQ llhXeHcb/wabMPkP2n81ocAIoLZrMqn/4y2RwP8DcQ+d6rT9ATiAAAAAElFTkSuQmCC

http://zilvia.net/f/data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABwAAAAOCAYAAAA 8E3wEAAAABmJLR0QA/wD/AP+gvaeTAAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB3RJTUUH1Q UUDyoqJjAqRwAAAN1JREFUOMu1lMkVwyAMBYe0JGpCNUFNVk3k 4AUwxPGS+ILxkzX8jyTH/Sfu9nrmJ3cXlnMASyWRPwd2d5XlHCBZn1BthcbRAdxTZQDI8k3 mQzg11rhF+QZ9jdNOcQib6GFQYJYgCFucSRf6GsLU6wEY5yubT FqF2yq1vRwr3INXdQUWG+je1pELX4ED1wDyRAR0WfuAA9gloIT yvsFMIMgYInYRqF6rO9Sqz9qkO5ilyo0o3YBwJ+6vrdQonxWUQ llhXeHcb/wabMPkP2n81ocAIoLZrMqn/4y2RwP8DcQ+d6rT9ATiAAAAAElFTkSuQmCC

The knock sensor (code 34) code is 90% of the time because of a short in your wiring to the knock sensor. Other times, the sensor itself has melted or been destroyed. It will not harm your engine driving like that. However, because that code 34 is stored on your ECU, you will notice your engine produces a lot less power than normal (timing is retarded to prevent knock). To fix the issue you need to find the short in the wiring and splice/solder to repair it (or replace the sensor itself if it's bad). If you search around for "code 34" you will find many posts on the topic, where to look for the short, how to replace the knock sensor, etc. It's a common issue on the KA24DE.

IACV I don't know the solution, you may have a short or the unit itself might be bad/gummed up/etc.
I'd try what he said check resistance with a meter and check for continuity to ground

[surreybc]

google 240sx iacv tutorial. there are a number of electrical things that could be wrong with iacv.

[nismo 240sx]

thanks you guys ill do it tommorow since it is my day off!