Strange Electrical Issue

[Daskuppler]

Hello Everyone!

The problem child is a 2002 Impreza TS with 145k on it.

Over the last week or so, my radio has been acting weird, I assumed it was failing since it's 10+ years old. The volume would randomly dip to 0, then back to 10, turn off, restart, sometimes even staying off, etc

Today, while on a drive through the mountains and coasting down a hill at about 70mph, the check engine light comes on, radio starts acting up, then the ABS light comes on and the tachometer goes to 0...all other gauges were working including power steering and brakes. Hitting the accelerator did nothing. I pushed in the clutch, gave it some gas, and RPMs went up, then fell to 0 again. During this time, the CEL was flashing (though not like the severe misfire flashing). Flashing and the radio volume were in sync with clicking relays on the passenger side (sounded like it was in the kick panel, but I'm not certain). ABS light goes off about 2 miles later, radio returns to normal operation and the car drives fine for another 70 miles.

Next long descent and all symptoms return. I took the next exit, restarted the car and it never happened again (another 200 miles until I got home). I later noticed that the clock on the dash had reset like it lost power (the time would indicate that it happened during the first instance. CEL turned off on the way home.

When I got home, I had two codes:

P0335 (stored) crank shaft position sensor A circuit

ABS 22: FR wheel speed sensor.

I went to scan again and the ABS module won't scan, and my code reader keeps disconnecting after displaying the p0355.

No work has been done in the last 4,000 miles and the car drove fine after the restart.

Thoughts?

Edited May 28, 2024 by Daskuppler

[brus brother]

alternator?

[Daskuppler]

4 hours ago, brus brother said:

alternator?

Alternator is old, but I e never had any battery issues. I'll test it though

[nvu]

When you mentioned clicking relays, were they fast machine gun clicking?  And by chance does your car come equipped with the subaru security alarm?

Edited May 28, 2024 by nvu

[Daskuppler]

6 hours ago, nvu said:

When you mentioned clicking relays, were they fast machine gun clicking?  And by chance does your car come equipped with the subaru security alarm?

It was slower than that, you could count them (but barely).  No Security alarm, it's the TS so it has almost nothing

[nvu]

I see, not the same issue then.  I had a security alarm module on an older 98 go bad.  It would toggle off and on really fast randomly, apparently it toggled the main relay along with it and would throw all sorts of lights.  All the issues went away after removing the module and rewiring the car back to stock.

[Daskuppler]

4 hours ago, nvu said:

I see, not the same issue then.  I had a security alarm module on an older 98 go bad.  It would toggle off and on really fast randomly, apparently it toggled the main relay along with it and would throw all sorts of lights.  All the issues went away after removing the module and rewiring the car back to stock.

Ia had a similar issue on our Xterra,  it no "fancy" things on this one haha

[wtdash]

-Battery? verify no corrosion on terminals.

-Check grounds - Subarus have them in multiple places around the engine. 

And on my Forester, w/the same CS sensor and same code   - P0335- I had a loose connector that caused a no start one day...but likely just forgot to 'click it' when I last worked on the engine. 

[Daskuppler]

8 hours ago, wtdash said:

-Battery? verify no corrosion on terminals.

-Check grounds - Subarus have them in multiple places around the engine. 

And on my Forester, w/the same CS sensor and same code   - P0335- I had a loose connector that caused a no start one day...but likely just forgot to 'click it' when I last worked on the engine. 

I'll check it the CS wiring, it was likely unplugged when I did the head gaskets a while ago, maybe it didn't get quite plugged in. The battery is good, it's a red top Optima and only a few years old.

I'll check the grounds, hopefully it's something that simple.  I've not had an issue since, not even the radio which was pretty consistent beforehand.

[Daskuppler]

Grounds in the engine bay were good, battery terminals tight, and alternator tested good.

[el_freddo]

Get your battery load tested. Doesn’t matter what brand or how old it is - batteries fail all the time. 

Some go a long time, some die a week after fitting to a vehicle. 

My 5c at this point. 

Cheers 

Bennie

[Daskuppler]

Battery, starter, and alternator were tested and all were fine except reserve capacity in the battery. CCA and voltage were fine.  Car had been sitting about a week and driven for about 20 minutes prior to the test.

[Daskuppler]

So about a year a go, I replaced the main ground contact on the block under the air box.  It was green, no copper insight.  I cut it back to fresh copper, put a new end on it, and called it good.  At the same time, I replaced the battery with a new AGM. 

I had no further issues until today.  The radio started flickering again. I also noticed that my key no longer stays in the ignition when the car is running.  It's old and this isn't my only car with this "issue".  My question is, could this be an issue in the ignition switch since the dash/radio/clock all flicker periodically?

I guess I'll continue chasing grounds down...Any other suggestions?

[wtdash]

I've read about the ignition wearing out on other cars and causing similar symptoms, so likely Subars can too. 

[Daskuppler]

4 minutes ago, wtdash said:

I've read about the ignition wearing out on other cars and causing similar symptoms, so likely Subars can too. 

Any idea if it can be metered to see if it's bad in some capacity?  I'll look into it further and see what I can figure out.

[wtdash]

^No - not something I've done. Just read about. 

[Daskuppler]

I went to start the car this morning and got a couple dim and blinking lights on the dash. No cabin lights and the car wouldn't start. 

 

Battery is charged and it drove fine yesterday

[lmdew]

Quote

Relay's in the kick panel.  Pretty easy to change.  LOADPro will work with your meter to load the circuit.

 

[Daskuppler]

I ordered some wire and terminals for the big three mod to see if that helps a little as well.

[jonathan909]

Wow - this has been dogging you for more than a year?  Awful.

This is not going to be easy.  It's easy to say "look for a bad ground".  It's quite another to find it.  Get the drawings for your exact model and year, because here minor variations count.  Then trace every ground and +12V wire, and make sure that both the wire itself and the terminations are good.  Here's the example I usually cite:

I had a 1997 Jeep Grand Cherokee before moving to Subarus.  Ran great for years, until the high-miles motor blew (rod through block).  Then it sat over a winter until I dropped in a new engine in the spring.  When I started it up again, all of the electricals were wonked out.  Turning on the stereo affected the wipers.  The lights affected the heater.  All of this unrelated stuff was suddenly functionally coupled in the most chaotic manner.  I bought the big thick book for that year's model from Chrysler and started tracing wires.  Eventually I found that where the big harness passed through the firewall (in the most inaccessible spot, of course), a tiny pinhole in the insulation on a +12V wire had let in enough moisture over time to corrode clean through the copper conductor.  Absent that supply line, a bunch of stuff found alternate supply paths - through other things, the result being that both were semi-powered and acted nuts.  The lesson is that because the effects were so random and crazy, it would have been a waste of time to try to think them through - you just have to check every wire that can have that kind of global effect, what we call "exhaustive search".

The other example is a simpler one:  After I had the motor out of my (first) '99 Outback for I-forget-what, the AT got all kooky - the shift points were all over the place.  Everything else in the car was fine.  Turned out that I hadn't tightened down that big, most-obvious-ground-in-car ground lug on top of the intake.  Tightened it and all was well.  So the effects can can be globally insane, or just localized to some weird thing.

 

[jonathan909]

On 7/24/2025 at 8:15 PM, wtdash said:

I've read about the ignition wearing out on other cars and causing similar symptoms, so likely Subars can too. 

That's a really weird thing to say.  What does "ignition wearing out" mean?

[forester2002s]

Agree on both points. Electric gremlins are difficult to corner and deal with. And there are multiple ground-points to worry about.

My philosophy on grounds is that you can never have too many grounds (I'm not totally convinced that this is always true). So rather than chasing bad grounds, it might be quicker to just add grounds (in strategic places).

[jonathan909]

On your philosophy of grounds, Disagree Strongly.

You can, in fact, have too many grounds, though probably not in this context, rather in small-signal applications that are really noise-sensitive.  In that case an excess of grounds can result in what are called "ground loops", which behave like little circuits of their own in which very small currents can circulate and disturb the performance of other circuits, notably amplifiers, which will raise the voltages created by those circulating currents to a point at which they become interference.  And while you may think you're being "strategic", you may discover that the electrons do not agree.  So while you can often get away with adding grounds arbitrarily, they can come back and bite you in the @$$.

Plus, in the Jeep case I cited above, that wouldn't have helped anyway, because it was a +12 line that failed, and the problem wasn't going to be solved without first identifying exactly which one it was.

Edited 13 hours ago by jonathan909

[wtdash]

16 minutes ago, jonathan909 said:

That's a really weird thing to say.  What does "ignition wearing out" mean?

? weird? How? Maybe I should be more specific to the 'ignition (edit) switch where you put the key in can wear out', but in the context of the previous post, I 'assumed' it was implied. 

Quote

I also noticed that my key no longer stays in the ignition when the car is running.

 

Edited 13 hours ago by wtdash

[jonathan909]

Oh - you meant the ignition switch.  Okay, no argument there at all.  Mechanical contacts like that degrade over time, and (as I proved years ago) that's exactly the reason for you not being able to program for your key fobs anymore.

But "the ignition" refers to the whole system, and that would have been a bizarre claim, kind of like "my windshield wore out".  "Cracked?  Pitted?"  "No, just wore out, stopped working, can't see through it anymore."

 

Edited 13 hours ago by jonathan909