97 Legacy Wagon BAD ECU???

[Davee]

So I've recently purchased this 1997 Subaru Legacy EJ22 Wagon with 145k on the odometer in hopes i can sell my ford and embrace the Subaru life.

 

Story is its been sitting for 6 months and needs an ECU idk why the ecu went bad? but its a no start/but cranks no spark. I've checked all the fuses & relays plugs and wires. I've replaced the fuel pump as well & jumped it to see if it was bad or not. Fuel pump turned out to be fine. I'm not much of a mechanic but if someone could shed some light on the or suggestions. I currently have 3 ecus which i have no idea which was the original one, BUT none of them do anything when plugged in. One is from a 98 Impreza another is from a 98 legacy wagon.

 

I currently have a dealer appointment to flash one of these things and hope it starts. Should i do this or get an exact one on eBay and try it? Can i get around not going to the dealer to fix this issue.

 

This legacy is to cool to send to the scrap yard! Help Wanted!!!

[doublechaz]

What are the numbers on the ECUs you have? We should be able to use that info to figure out which ECU to use.

 

It's not very likely to be a dead ECU unless it was under water or severely mis-connected. You can take the cover off the ECU and see if anything is water corroded or burned up.

 

It is more likely to be a wiring or sensor problem. If the ECU doesn't know what the crank or cam position is, it won't send spark and fuel signals.

 

Do you have service manual? What kind of electrical test gear do you have?

[Rhineholio]

Check the grounds! You can check for power at the pump too with a power probe or volt meter. That will tell you if the ECU is working or not. The cam and crank sensors are things to look at. Take one of the cam sprocket covers off and take a peak at the timing belt. Mine deteriorated because of a powersteering leak and the cords got wrapped around the crankshaft sprocket so the sensor couldnt read it.

[Setnev]

The 96-98 ECU from a Impreza, Legacy, Outback, and Forester were all plug n play. If you swapped one out for another and you get the same result, the ECU is not the culprit. Dont waste your money on "flashing" or "reprogramming" the ECU. It's not necessary. You need a factory service manual and, at a minimum, a multimeter. You're going to need to run through the diagnostics section until you come to a resolution. There are so many variables that will cause a no start condition. ECU is the last thing that should be replaced.

[Davee]

I’m getting conflicting information everywhere..

If someone can confirm these ECUs should be plug and play to start the engine

Aside from phantom codes? Reader says Failed Connection every time

Engine light stays on some things in car work door beep stereo & some other minor things.

 

I really don’t want to pay the dealer anything if I don’t have to.

There is also no power getting to the fuel pump, but it was jumped and heard it running briefly.

 

Is any of this indicative of timing belt issues or jumped teeth bent valves..I really don’t know. I paid a mechanic the other day to try and figure it out and he came up empty handed as well and pointed me to the dealer for maybe flashing an ecu which I really don’t think is the problem now.

 

If anyone can help it would be greatly appreciated.

I’m thinking a checklist of what it could be possibly if anyone has that.

 

ECU1- http://i65.tinypic.com/2cijkn9.jpg

ECU2-http://i68.tinypic.com/1z4wr48.jpg

ECU3-http://i65.tinypic.com/ouxoqf.jpg

[Davee]

ECU1- Is the Original 97 Legacy Wagon 2.2

ECU2-99 Outback Legacy 2.5

ECU3- 98 Legacy Wagon EJ22 MT

[doublechaz]

First task is to get a Factory Service Manual for the 97. Somewhere in there should be a flow chart of how to trace this.

 

Meantime, I would take apart and clean the grounds you can find. Then I would inspect as much of the wiring harness as you can for rodent chews, pinches, abrasions, etc.

 

Not getting anything from the ECU through the diag port indicates that it probably isn't powering correctly.

[Rhineholio]

Typically the dealer isn't the best source. They hire kids and usually only want to work on newer cars. Your best bet is to find someone who knows Subarus.

 

if you get a connection failed for the OBD port then Id start looking at a wiring diagram starting with the OBD port.

 

Did the car come with an ECU? Id put that one in and try testing everything. As someone said the ECU probably isn't the problem.

[Setnev]

I’m getting conflicting information everywhere..

If someone can confirm these ECUs should be plug and play to start the engine

Aside from phantom codes? Reader says Failed Connection every time

Engine light stays on some things in car work door beep stereo & some other minor things.

 

I really don’t want to pay the dealer anything if I don’t have to.

There is also no power getting to the fuel pump, but it was jumped and heard it running briefly.

 

Is any of this indicative of timing belt issues or jumped teeth bent valves..I really don’t know. I paid a mechanic the other day to try and figure it out and he came up empty handed as well and pointed me to the dealer for maybe flashing an ecu which I really don’t think is the problem now.

 

If anyone can help it would be greatly appreciated.

I’m thinking a checklist of what it could be possibly if anyone has that.

 

The reader showing "Connection Failed" tells me that there is a main that has been tripped. Further evidenced by the fact that you're getting no power to the fuel pump, and possibly other systems as well. The underhood fuse box has a fuse labeled SBF-2, which coincidentally, provides power to not only the OBD port, but the ECU, the fuel pump relay, and the main relay (inside the car near the ECU). Have you checked this fuse? If so, get a different code reader and try it. Some of them have trouble with our ECUs due to the protocols used. I have had particularly good luck with the OBDLink MX Bluetooth readers.

 

Here is a link to your service manual: 97 Legacy-Outback FSM

 

Download all of the sections (PDF) in the main directory to your computer. Next, put ECU 1P back into your car. The section you're going to want to focus on from the FSM is the Diagnostics Section and second to that is the Wiring Diagram.

 

Report back if SBF-2 is blown. Don't just visually inspect it, probe it with a multimeter to check it's continuity.

 

If the fuse is good, this is a relatively simple circuit to diagnose if there is a break due to the fact it only goes to 3 places and runs off the same wire.

 

If for some reason the fuse isn't blown, you're going to have to check circuit MB-3 down to every connector and component. The first stop that circuit goes is into the cabin. It connects to bulkhead harness connector B62. You'll want to pull that connector apart and check pin 10 (solid red wire) on connector F45. It is high up under the dash (see pic below). To test, turn the key on and see if you get any voltage to that pin. If so, move on, if not, you need to find the break between the front fuse box and the connector.

 

 

If you get voltage on F45 pin 10, plug it back in to B62. Find the fuel pump relay, connector B46, and the main relay connector, B47. They above the interior fuse panel, you can't miss it. B46 is a 4 pin green connector with a black/red, yellow, violet, and red wire. B47 is right above it and is a 6 pin brown connector. On B46 (fuel pump relay), probe the red (pin 2, upper right pin) with a voltmeter. If no voltage, repair harness. If you have voltage, probe both red wires (pin 5 and 6 on the bottom) on the B47 connector. If no voltage, repair harness. If you have voltage, test the OBD connector next.

 

On the OBD connector, probe pin 1 (you guessed it, red wire) with a voltmeter. You should get 12v. If not, repair the harness. If so, test the ECU wiring.

 

On the ECU connector, probe pin 39 with a voltmeter, You should get 12v. If not, repair the harness.

 

I am willing to bet that the fault is going to lie with either the fuse being blown, the connection for the fuse is loose, or the harness has a short from the fuse to the F45 connector inside the car.