My check engine light on the 96 2.5 outback wont come on when i try starting the car.I have changed ecu s and the light bulb behind the dash and still nothing.The bulb was burned out before i replaced it.The ecu is out of a 95 outback with a 2.2 in it and it was wrecked so im pretty sure it was working.I need to get this car going and ive changed alot of parts ecu,cps,ignitor,belt ,and relays,about the only parts that havent been changed are coil and crank angle sensor.

Check the replacement bulb to see if it burned out.

 

nipper

Check the replacement bulb to see if it burned out.

 

nipper

i tried 2 more bulbs in its place and still no light.

Well check the bulbs with an ohm meter. Next check the wire in the ECU connector to make sure its good.

I cant find my book, so i am not sure if the CEL light signal at startup comes from the ECU or from the ignition switch or some other circuit. Check the connector at the ECU to make sure all the pins are making contact.

 

nipper

Well check the bulbs with an ohm meter. Next check the wire in the ECU connector to make sure its good.

I cant find my book, so i am not sure if the CEL light signal at startup comes from the ECU or from the ignition switch or some other circuit. Check the connector at the ECU to make sure all the pins are making contact.

 

nipper

i was able to get the check engine light to come on after putting the test light probe in the back of the wire going to the ecu,the light woudnt stay on unless the test light probe was on the wire.could be a bad ground? and causing the carnot to start?

Here is what i had to do to getthe check engine light to come on.

i tried to post pics but wasnt able to.

Is your ECU getting power?

the violet wire going to the ecu is getting power but notthe white blue wire.

From what I have seen in the past, the CEL light is grounded through the ECU. My info shows that the light is provided power through fuse #15 and ties to the light. The return for the light goes to pin 58 of the ECU. Check your fuse panel for a bad fuse.

 

The same fuse also provides power to pin 7 of the check connector in the center of the instrument panel.

From what I have see in the past, the CEL light is grounded through the ECU. My info shows that the light is provided power through fuse #15 and ties to the light. The return for the light goes to pin 58 of the ECU. Check your fuse panel for a bad fuse.

 

The same fuse also provides power to pin 7 of the check connector in the center of the instrument panel.

with the check engine light light only coming on when i put the test light probe in the back of the ecu mean that there is a short in the ecu?i checked all the fuses andthey looked good.

No that would mean that there is something wrong with the harness, connector or wire that feeds the light. If it comes on at the ecu and the signal isnt being carried to the dash, means (to me without seing it myself) the ECU works fine.

 

nipper

Nipper is correct. The test light should turn on when you are on the wire opposite the ECU connection since that wire should be tied directly to power. If you have proved that power is available after the fuse using your test light, then the wire connection between the fuse panel and the light is broken.

 

Since you state that the light is turning on at the ECU connection, and I assume that the test probe you are using is being clipped to ground while doing this, it means the ECU is not switching to ground. If you are testing the connection when the light is supposed to be ON then it seems something is wrong with the ECU also. In the past, I have replaced damaged IC's in the ECU that control that circuit.

Nipper is correct. The test light should turn on when you are on the wire opposite the ECU connection since that wire should be tied directly to power. If you have proved that power is available after the fuse using your test light, then the wire connection between the fuse panel and the light is broken.

 

Since you state that the light is turning on at the ECU connection, and I assume that the test probe you are using is being clipped to ground while doing this, it means the ECU is not switching to ground. If you are testing the connection when the light is supposed to be ON then it seems something is wrong with the ECU also. In the past, I have replaced damaged IC's in the ECU that control that circuit.

I have tried both ecu s and the same thing happens with both.The light on the test light is dim while cranking over.I am starting to think maybe the ecu s are not grounding out.My electric door locks are now working and were not before the car broke down.also the ignitor and injectors are not getting a signal from the ecu.I can also hear the relay clicking when i put the test light in the back of the violet wire at the ecu.

I recommend you first find out why the voltage is not getting to the MIL light from fuse #15. Also check the grounds going to the ECU for any problem. A bad ground connection will cause this kind of thing to happen.

I recommend you first find out why the voltage is not getting to the MIL light from fuse #15. Also check the grounds going to the ECU for any problem. A bad ground connection will cause this kind of thing to happen.

i checked all the grounds in the engine compartment and they looked good ,even disconected them and cleaned them up.I did notice when i put the cable on the battery teminal from the main fuse box in the engine compartment that it sparks.

A little sparking is normal when you connect the battery. Normal current draw when the car is parked should be around 25 to 80 milliamps, that is used for memory power.

 

How do you check the grounds? Did you just look them over or use a meter to check for voltage drop across them? The ECU grounds are under the dash I think.

A little sparking is normal when you connect the battery. Normal current draw when the car is parked should be around 25 to 80 milliamps, that is used for memory power.

 

How do you check the grounds? Did you just look them over or use a meter to check for voltage drop across them? The ECU grounds are under the dash I think.

I just checked the ones in the engine compartment ,wire brushed them and looked them over.i will check the ones under dash.