ECM error code P1518

[Triathletedave]

Getting closer to a running engine all the time, but this last issue has us all stumped. With everything else apparently in order (no error codes), when we try to start the engine, we are not getting any spark at the plugs.

The battery is strong and running at 12.08 volts, the fuel pump is great now, but no spark. We confirmed that the donor did not have an Immobilizer unit installed, so we cannot determine why there is no spark. Maybe some issue at the coil? The only error code that comes up is P1518, but the descriptions of the possible issues have not led to a solution.

Any suggestions or insights?

Dave

[JeromeS13]

What are the details of your donor?

[Triathletedave]

What are the details of your donor?

2005 Impreza RS wagon. 2.5L SOHC normally aspirated engine. No Immobilizer system in it.

[philly15]

you don't have the test mode connectors connected do you?

[Triathletedave]

you don't have the test mode connectors connected do you?

Ran a scan without them connected, and then again with the test connector connected. No codes at first, and only the 1518 code with them connected. Did not attempt to start the car with the test mode connected though.

[Bob_n_Cincy]

Hi Dave
the P1518 code indicates that the 12 volt starting signal is not getting to the ECU.
I don't have an 05 NA schematic. But in the 06 NA schematic it is ECU connector C pin 32 Yellow wire.
This wire goes 3 places.
1. Starter interlock relay pin 28
2. ECU pin C32
3. Starter solenoid spade connector.

I know the wire is going from the relay to the starter because the engine is turning over.
Check the voltage on ECU pin C32 during cranking.
Bob

[Triathletedave]

Thanks Bob. I'll find and check that line. Since the starter is working fine, I was expecting an error code related to the coil.

I was also considering whether the ECU was acting as if an Immobilizer had been present, and the coil power was cut by the ECU because there is no signal from an Immobilizer. A long shot since the car never had an Immobilizer, but still possible.

[Triathletedave]

Looks like no voltage in ECU pin B8. Does that mean a problem with the starter interlock relay?

[Bob_n_Cincy]

Looks like no voltage in ECU pin B8. Does that mean a problem with the starter interlock relay?

The relay is good because the engine is cranking.

You should be looking at pin D8 (not B8) was that a typo?

Where does wire D8 go to?
Where does the start wire off the solenoid go to?

If you are cranking. We know that 12 volts is on the yellow wire going to the starter.
There should be a connection from this wire to D8 on the ECU
Bob

[Triathletedave]

ECU pin C32 goes to the mass air sensor on mine. I followed the lines back from the starter interlock relay, and it is a yellow wire going to ECU pin D8, and the rest matches your description. I'll test that line for voltage.

[Triathletedave]

Yes, that was a typo. It is D8. D8 is a 16 guage yellow wire that splices into the heavy guage starter solenoid, the ignition switch, and the starter interlock relay.

[Bob_n_Cincy]

Yes, that was a typo. It is D8. D8 is a 16 guage yellow wire that splices into the heavy guage starter solenoid, the ignition switch, and the starter interlock relay.

Since the starter is getting 12 volts, Pin D8 should be getting 12 volts.

Not sure if this has anything to do with problem. DO you have you ground strap from engine block to frame installed?
Bob

[Triathletedave]

Since the starter is getting 12 volts, Pin D8 should be getting 12 volts.

Not sure if this has anything to do with problem. DO you have you ground strap from engine block to frame installed?
Bob

Yes, we were careful to strip the powder coat and paint on the contact points on the frame and engine. I'll try a different voltage meter to seeif I get anything different on D8.

[Triathletedave]

Changed out the voltage meter. Now I see 12 volts during ignition (starter engaged). So D8 should be ok then?

[Bob_n_Cincy]

Hi Dave
Can you clear the P1518 code and then watch to see if it comes back?

[Triathletedave]

Hi Dave
Can you clear the P1518 code and then watch to see if it comes back?

I will certainly try that today. Since most everything else works, I want to focus on the coil wiring, and see if there are any issues there. I may run a new power line direct from the battery to the coil, using an in-line fuse. Maybe add a second ground wire, then test the two wires to the ECU. I can't think of anything else to check or test after that.

[Triathletedave]

Hi Dave
Can you clear the P1518 code and then watch to see if it comes back?

Cleared the codes, then I got P0335 (crankshaft position) and P1518 after that. Not sure why the crankshaft error came up this time.

[Bob_n_Cincy]

Cleared the codes, then I got P0335 (crankshaft position) and P1518 after that. Not sure why the crankshaft error came up this time.

Hi Dave
I'm in over my head. I don't know what to tell you at this point.
This is what I would do.
Connect my meter black lead to actual negative battery terminal.
Measure each ground point into the ECU to make sure it is below 1 volts during cranking.
Measure each 12v point into the ECU to make sure it is above 10 volt during cranking.
Bob

[CanadianYank]

Hi Dave
I'm in over my head. I don't know what to tell you at this point.
This is what I would do.
Connect my meter black lead to actual negative battery terminal.
Measure each ground point into the ECU to make sure it is below 1 volts during cranking.
Measure each 12v point into the ECU to make sure it is above 10 volt during cranking.
Bob

Hey Bob,

Dave is really close so I'm heading over tomorrow with Fluke and Oscope in hand. Ill check that and verify the crank sensor signal as well. If you can think of anything else let us know...

Frank

[Triathletedave]

Hi Dave
I'm in over my head. I don't know what to tell you at this point.
This is what I would do.
Connect my meter black lead to actual negative battery terminal.
Measure each ground point into the ECU to make sure it is below 1 volts during cranking.
Measure each 12v point into the ECU to make sure it is above 10 volt during cranking.
Bob

Thanks Bob. Your guidance and suggestions have been extremely helpful! I'm just hoping that the final solution is something simple.

The first time we turned the key, absolutely nothing happened. After a bit of head scratching, a buddy asked if we need to depress the clutch first. That sure was a 'Duh' moment! Maybe we will have another flash of brilliance like that tomorrow.

[CanadianYank]

http://forums.nasioc.com/forums/showthread.php?t=691943

Hey Dave check this out, Possible immobilizer?

Frank

[Triathletedave]

I still think that this is highly unlikely. The donor was my daily driver for over a year, and I have never seen any indications that an aftermarket Immobilizer was installed. I have confirmed that the Canadian version of the 2005 Impreza only had a factory Immobilizer on the STI model, not the RS.

Is it possible that the ECU has a 'default' setting to look for an Immobilizer when it is first powered up? That could explain it. If that's true, then the ECU would need to be reprogrammed before we can start the car.

Anyone else run into this?

[Triathletedave]

Ok, so Frank came over today with his bag of tricks, and we went through each system and wire that could impact the ECU sending spark signals to the coil. It turns out that we had a bad wire between the crankshaft position sensor and the ECU. Since the ECU was not getting a pulse from the crankshaft sensor, it was not sending a spark signal to the coil.

We bypassed the bad wire temporarily, and the engine started right up! The P1518 code was of no use or value. We needed to see code P0335 (crankshaft sensor) to be of any use.

Huge thanks to Frank for figuring out the issue, and to Bob and all other posters for helping me move in the right direction!

[CanadianYank]

Dave, Thanks for the invitation, I had fun and it was great to be with you on your first start! You are really doing a great job with your build and I look forward to seeing the finished product! Also thanks to Subaru for the laugh about DUH Code P1518, your engine failed to start... LOL

Frank

[Bob_n_Cincy]

Great News Dave. Now The rest sorted out so we can see your first go kart video

[Triathletedave]

Great News Dave. Now The rest sorted out so we can see your first go kart video

Yes, soon I hope! Frank graciously took a video of the first start, and I hope to get a video of the first go-cart soon too. Better hurry - the snow is coming!

[CanadianYank]

Yes, soon I hope! Frank graciously took a video of the first start, and I hope to get a video of the first go-cart soon too. Better hurry - the snow is coming!

Dave, Here ya go...

[AZPete]

Congrats on the start! Yes, it sounds sweet.