07 S40: Electrical Gremlins Troubleshoot (i.e., anti-skid, crash mode, radio going off, engine shutting off)

[theWIFES_S70]

I've had our 07 S40 for about five years now. Car has been an absolute dream. Work completed: timing belt, water pump; plugs and coils; Sachs struts and Volvo shocks; control arms. I can't recall anything else. About two and a half years ago, I started noticing every so often, the lights would dim and the dash would flicker when turning the wheel. When I got the car inspected I asked my mechanic to check out the amperage. All looked okay. In fact, he could not recreate the "dimming" headlights. Told me not to worry about it.

About half a year ago, the dimming lights get worse getting some inconsistent idling, too. So I decide, well, it's the original alternator and pulleys, so might as well do this job. This is the N/A so it's a pretty straightforward job.

All good pretty smoothly. Turn the car on and she fires right up immediately. The alternator seems to have a very different "whirr" to the old one, but all good. Car turns on instantly. Lights are brighter. No dimming headlights. All seems incredible.

About a 150 miles after the job, I'm on the Throggs Neck bridge and the "anti-skid" light starts flickering on and off. Seems weird. I didn't hit a bump. I don't really drive fast. No furtive movements. Just minding my own business at the speed limit. Nothing seemed out of the ordinary. I get one or two wonky idles, but the car doesn't shut off. I get home and am able to park the car.

Two days later, I have to drive again. I imagine the car won't start, but no, it starts right up. Sounds good. And I drive. I park the car that day and ten hours later when I want to drive home, the car will not crank over. I furiously look on Youtube for a solution and someone says, just disconnect battery cables and touch them and you should be good to go. I do this and car starts right up again.

So this has been the last four months. Here are some specific details.

Every hundred miles or so, a "little chirp" comes from the pulleys. The chirp means I'm going to get an anti-skid light and/or a crash mode light soon.

If I pull over, shut the car off, pull key out and turn back on, chirp is gone and I can drive the hundred miles or so. To prevent this, every other drive I just preemptively disconnect battery cable. All has been good so far.

I got these parts from FCP so I'm thinking I'll just swap in some new pulleys and see if the "chirp" goes away... There's a "slight" mm difference in lengths between those two alternator belts, maybe I mixed them up somehow? But how does this make sense at all? There's no sensor connected to the pulleys, is there?

Any thoughts would be greatly appreciated... It's a five-speed and I'm starting to think the end is nigh and it's a heartbreak...

[RobsS40]

Never give up! We can never let the gremlins win. You may have swapped the 2 belts. It should be fairly obvious if the tensioners are somewhere in their normal range of travel.

As much as I love driving my S40, I'm very disappointed in Volvo for a few things: lack of gauges. One of my first problems involved low oil pressure. The light came on, but at that point you're into engine damage if the RPMs are high. So I put in an oil pressure gauge. Discovered, by trial and error, I just needed to change out my oil filter. Previous owners probably not changing oil often enough, my new clean oil cleaned out the crud and clogged the filter. On my third filter in 2700 miles.

Strongly consider a volt meter.

You might have a loose electrical connection somewhere. I found and fixed many, including the grounding points.

[RobsS40]

I meant to add: disconnect the battery then be sure to check the bolt-down fuses. The bolts / screws / fuse contact points can develop a very thin layer of corrosion under them. Corrosion is insulator. I use many methods of cleaning the contact surfaces, then a light film of silicone or just some other clean grease. Be sure you don't leave abrasive granules on the contact surfaces if you use sandpaper or other abrasive like ScotchBrite. 2 really big fuses at battery terminal, and at least 4 in fuse box. Again, then all the grounds, which are mostly on the shock towers (easy access).

Also, after disconnecting the battery, disconnect and reconnect every connector you can, especially CEM top and bottom. Some people exercise them dozens of times. Probably not necessary, but try to inspect each up close, good bright light, and coat with silicone, exercise a few more times.

Wire harness okay, no cuts or other damages? I've found oil spilled, esp. used oil from changing filter, rots the loom and embrittles the wire insulation, causing cracks, baring the copper, and potential shorts.

[theWIFES_S70]

I meant to add: disconnect the battery then be sure to check the bolt-down fuses. The bolts / screws / fuse contact points can develop a very thin layer of corrosion under them. Corrosion is insulator. I use many methods of cleaning the contact surfaces, then a light film of silicone or just some other clean grease. Be sure you don't leave abrasive granules on the contact surfaces if you use sandpaper or other abrasive like ScotchBrite. 2 really big fuses at battery terminal, and at least 4 in fuse box. Again, then all the grounds, which are mostly on the shock towers (easy access).

Also, after disconnecting the battery, disconnect and reconnect every connector you can, especially CEM top and bottom. Some people exercise them dozens of times. Probably not necessary, but try to inspect each up close, good bright light, and coat with silicone, exercise a few more times.

Wire harness okay, no cuts or other damages? I've found oil spilled, esp. used oil from changing filter, rots the loom and embrittles the wire insulation, causing cracks, baring the copper, and potential shorts.

Thanks Rob, I appreciate the support! Still driving by resetting the computer after every long drive... I'll give it a good check when it gets a little warmer... I do remember coming across a Youtube video about making sure to clean all the wire harness contact points to clear electric gremlins.

SEE: https://www.youtube.com/watch?v=H_M0KW3 ... YW5pbmc%3D

[theWIFES_S70]

UPDATE: So driving the other day, the radio made a sound... like a needle being scratched on a record and then the radio stopped working altogether before the anti-skid stuff starting appearing again. I pulled over and reset the car computer and for the last 150 miles, no anti-skid light. I am going to leave the radio off from now on. Maybe this is the hack???

[RobsS40]

I'm with you on wanting warmer weather. We've had some really nice days. I'm just a little south of you. That new radio sound symptom is very troubling. As an engineer I'm very unhappy with CAN bus. It's not fault tolerant- has no business being in a car. No clue what the thinking is. Anyway, yeah, the radio noise might indicate something crazy going on somewhere, getting into one or both CAN busses, causing who knows how many error codes, when the actual systems are just fine.

My S40 has been mostly okay. One day it went berserk- the infuriating "reduced performance mode" when there was nothing wrong. A little embarrassing- I was in a fairly well-to-do area- had to get out, disconnect battery, reconnect, get back in, car started and ran perfectly. More and more I'm thinking of wiring in a remote disconnect for the major electronics. Rumor has it there's a software upgrade that'll reduce or eliminate the "reduced performance mode" that otherwise wants to strand you and make you hate Volvos.

In another post I wrote about where I found CAN bus wiring violation- done by wire harness factory. Quite a bit of effort to pull it apart and do it right. CAN bus has strict rules about wire lengths, especially taps off the main bus pair- called "stubs". They must be less than 12". Mine was close to 24" down to EPS pump, and barely twisted. After fixing that the car has been almost perfectly stable. I have to wonder how many otherwise great cars are sitting in junkyards due to the wiring error. New the cars might have been okay, but as the car ages the CAN bus faults could become more easily triggered.

[theWIFES_S70]

I'm with you on wanting warmer weather. We've had some really nice days. I'm just a little south of you. That new radio sound symptom is very troubling. As an engineer I'm very unhappy with CAN bus. It's not fault tolerant- has no business being in a car. No clue what the thinking is. Anyway, yeah, the radio noise might indicate something crazy going on somewhere, getting into one or both CAN busses, causing who knows how many error codes, when the actual systems are just fine.

My S40 has been mostly okay. One day it went berserk- the infuriating "reduced performance mode" when there was nothing wrong. A little embarrassing- I was in a fairly well-to-do area- had to get out, disconnect battery, reconnect, get back in, car started and ran perfectly. More and more I'm thinking of wiring in a remote disconnect for the major electronics. Rumor has it there's a software upgrade that'll reduce or eliminate the "reduced performance mode" that otherwise wants to strand you and make you hate Volvos.

In another post I wrote about where I found CAN bus wiring violation- done by wire harness factory. Quite a bit of effort to pull it apart and do it right. CAN bus has strict rules about wire lengths, especially taps off the main bus pair- called "stubs". They must be less than 12". Mine was close to 24" down to EPS pump, and barely twisted. After fixing that the car has been almost perfectly stable. I have to wonder how many otherwise great cars are sitting in junkyards due to the wiring error. New the cars might have been okay, but as the car ages the CAN bus faults could become more easily triggered.

If you, as an engineer are having problems with this, what can I do?

How does one get this software upgrade? Do we have to find a mechanic in Sweden somehow?

You know how bad it's getting? I saw a Nissan Sentra the other day and said to myself, maybe that wouldn't be too bad...

The only value in my car right now is the sweet Manual Transmission and the engine that has had LiquiMoly the last 50K miles and has some Ceratec in it.

[theWIFES_S70]

Robb, have you seen this???

https://youtu.be/3iovw5rWkiY?si=p7sR1PfB-HaP5gtO

[RobsS40]

Firstly thank you for that link and information about the CFE. I'll be looking into that some more. It might be helpful, I'm not sure. I have a CANBUS <-> USB interface adapter and cable for the PC. I'm still learning about software. In fact I came here to post a question.

Re. software upgrade: I read it in forums, maybe here, that Volvo dealers can do the upgrade. I haven't inquired because it will cost more than I'm willing to sink into the car at this point. Maybe someday. For now I'm looking into what I can do myself with Vida and/or Vdash. I'm still pretty unclear on how that all works, and I came here to post some questions top-level forum.

Regarding the CANBUS wiring: well, yes, very very few car people would likely understand the intricacies of network wiring. Again, the physical wire, insulation, number of twists per unit length, distances, etc., are all very critical. As an EE and car enthusiast, I'm very disappointed that they (Germans) would use such a fragile design in a car. It would be okay if the protocol (rules for communication) would do a much better job of error recovery. One electrical glitch should never never shut a car down! The communication system can detect the glitch / noise / interruption, and request retransmission. These cars may do that somewhat, but not as robust as I'd design it.

Anyway, if you think you may have this problem, the only thing you can do is pull the wire harness apart. I had to remove the left-most (passenger side) engine mount and some other things to pull the cable out, remove the sticky tape wrap, and then I could simply see the error- much of it was not twisted, and the "stub" - the "T" in the main run that then runs down to the EPS (Electric Power Steering) pump was much too long. So I had to extend the twisted main pair down much closer to the EPS. That was some soldering, heatshrink tubing, etc., then re-wrap the harness.

Very interestingly: I have a friend who is a car nut, specifically German, especially Porsche, but he barely knows hands-on stuff. When I bought my S40 he suggested I replace the wiring harness. That stuck in my head- how did he know that? Why did he know that? I hadn't heard that before- is that commonly known that you need to replace wire harnesses? Maybe that's a German car thing? Remember, all electronics in this S40 are German (Bosch). Well, maybe not all, the CEM might be Volvo, but it "talks" to all the Bosch things so it has to follow the CANBUS rules.

Yeah, I don't know, if I had it to do over I'd have gone for a RAV4 or some such. I just wanted AWD, but I've always liked Volvos. TBH, I love driving this thing so much, that and it's a challenge to learn and figure it all out and get it working well.

I don't know if a new harness would be done correctly, BTW.

[theWIFES_S70]

i just found the PDF on how to address the water leaks... All I can say is this: was this car designed to be a car or a boat???

Rob, I like the idea of pulling and installing a new wiring harness... but absent a means of preventing water from getting into the car, this would only be a temporary solution. I love my engine, my manual transmission... but so defeated by this all. (Just spent a half hour taking water out of the backseat.)

ANOTHER GREMLIN UNLOCKED!!!
So, the daytime running light sensor... is kaput!

The autolight feature is no longer fully functional: daytime running lamps are still working, but when I shut the car off, the rear lights stay on... (and yes, the front ones go out.) So I'm switching to the "dipped" light position. All okay so far.