I'm not sure if everything you're describing is related. Instead of buying a ODB II scanner- many auto repair stores like Oriley's or Autozone allow you to use theirs to see what the codes are. Did you unplug any vacuum hoses before the PCV hose? Did you unplug the sensor near the spool valve and forget to plug it in? How are the grounds on the vehicle? Maybe a broken hose that connects to the air box?

My guess- and I'm just throwing a wild guess out there; you've possibly got either an unplugged vacuum line or some electrical plug has become unplugged (possibly near the spool valve). The VSA lights automatically come on with the check engine light and the weird idling is a result of either open vacuum line or important electrical component unplugged if it is related to what you are stating started after work was done to it.

If unrelated to work that was done, could be a broken air box hose, bad ground, worn spark plugs, or a host of other common issues. Edit: EGR valve could be culprit as well.

I'd start by looking near where work was done for any loose hoses or unplugged connectors, then borrowing or buying and OBD II scanner and see what it comes up with before further troubleshooting.

 

Thanks for your reply! The PCV hose is the only hose I had to disconnect. I'm not much of a mechanic, but I'm calling what I disconnected/broke the "PCV hose" because that's what the schematic in the repair manual says, even though it's no where near the PCV valve. I'm not exactly sure what you're referring to as a "vacuum hose" or an "air box hose" but it sounds like the hose I removed could fall under either of these descriptions. It's the only hose you have to remove to get to the spool valve. It's right on top of the intake manifold, on the left side of the engine above the spool valve and alternator. It's the short hose in the picture below with the red arrow pointing to it (what's in the picture is my temporary replacement from Autozone). Based on your description, it sounds like this "PCV hose" might be the issue, since it appears to be crimped (see right about where the red arrow is pointing). I've reconnected all electrical connectors, and in any case, it did drive fine for a day or so after I did this work, so if it were a disconnected connector, I'm assuming that would have shown up immediately.

In any event, I don't need to be driving it, so I'm waiting for a proper hose replacement to come in the mail so I can eliminate that possibility and then I'll drive it to Autozone to get an OBD scan.

 

While technically this hose is called the PCV breather hose but valve he PCV is on the opposite side, the driver side by the EGR vavle. I don't believe the PCV hose is the issue here but no way to say for sure without a scanner. I'd give everything in the engine bay a good look at since a connector could have gotten unplugged from a bump or maybe a wire hungry squirrel went and chewed up some wires.

 

Update: I successfully replaced the PCV hose, then changed the oil (it was low from the oil that was lost into the alternator). Reset the oil life to 100% (does this clear all error codes?). Still shaking, with check engine light, VSA system and VSA activation lights staying on. Took it to Autozone for an OBD scan. Here's what it said:

Most likely Solution: Reprogram Powertrain Control Module (PCM)

DTCs:

P0304 Cylinder 4 Misfire Detected
Secondary DTCs
P0420 Catalyst System Efficiency Below Threshold (Bank 1)
P0302 Cylinder 2 Misfire Detected
P0300 Random Misfire Detected
P0430 Catalyst System Efficiency Below Threshold (Bank 2)
P3497 1. Valve Pause System (VPS) Stuck off 2. Valve Pause System (VPS) Stuck Off Bank 2

83-13 ECM/PCM Relation Failure

61-22 Short in the left front seat belt buckle switch

61-23 Modulator-Control Unit Power Source Low Voltage

Here's the strange thing: on the drive home from Autozone, the shaking and VSA indicator lights were gone (still have the check engine light). So, for the first ~4 miles, I no longer have the problem. I'm leaning toward the remedies described in the following thread, starting with replacing some spark plugs, cleaning the MAF sensor, replacing the PCV valve, cleaning the ERG valve (new one is $$). The strange thing is, I can't find anything anywhere about "reprograming" the PCM, the 'most likely solution' according to the Autozone reader. Does "reprograming" just mean "resetting" it? Or is this something I just need to go to a dealer for? Also, I'm getting very confused about PCM vs ECM vs VCM. Are these all the same unit on a 2009 Pilot?

RESOLVED - wandering misfire - oil pressure/VPS related?

2011 Pilot Touring 4wd, 145k miles. It's had a history of electrical issues. I've been chasing a misfire on the front bank since the new year. It started at cylinder 4, briefly hopped over to 5 and has now firmly entrenched itself on cylinder 6. I've done the usual musical chairs of coils...

www.piloteers.org

 

If it were mine, I'd figure out:

P3497 1. Valve Pause System (VPS) Stuck off 2. Valve Pause System (VPS) Stuck Off Bank 2

Might guess the rough idle and other codes are related.

 

Update - Did the following:
1. Oil change (noted above)
2. replaced air filter and cabin air filter
3. cleaned MAF sensor with MAF cleaner (it looked pristine, but cleaned it anyway)
4. Replaced PCV valve (holy cow, that's a nightmare when the base snaps off. Don't think I'll try that again)
5. Cleaned EGR valve (it didn't look that bad, but cleaned it best I could using MAF cleaner)
6. Replaced all spark plugs (with $$$ NGK laser iridiums)

The rough idle/running came back, along with the VSA indicator light and VSA activation indicator light (i.e the orange ! triangle) Drove it to Autozone (~10mi round-trip, 19mpg per the car's dash read-out) and pulled the DTCs again:

P0352 Ignition Malfunction Cylinder 2
Ignition Coil B Primary/Secondary Circuit
83-13 ECM/PCM Relation Failure
61-22 Short in the front seat belt buckle switch
61-23 Modulator-Control Unit Power Source low voltage

Looks like I took care of the 04xx and 0397 codes with the emissions-related maintenance. Confirmed that connecting/disconnecting Coil 2 didn't make a difference, so following morning I swapped Coil 2 for Coil 5, and everything seems better. Went back to Autozone (~10mi round-trip, 24mpg per the car's dash read-out) and pulled the DTCs again now I've added the code in bold below:

P0352 Ignition Malfunction Cylinder 2
Ignition Coil B Primary/Secondary Circuit
Secondary DTCs:
P0355: Ignition Coil E Primary/Secondary Circuit
83-13 ECM/PCM Relation Failure
61-22 Short in the front seat belt buckle switch
61-23 Modulator-Control Unit Power Source low voltage

First question: I'm assuming "Coil B" is the coil on cylinder 2 (middle rear), and "Coil E" is the coil on cylinder 5 (middle front) - i.e. the coils I just swapped? According to Autozone, their obd reader does not 'clear' the codes, however on the drive home, no check-engine light, no DTS light, nothing! It seems to be driving better, and now the "ECO" light is coming on again, and as noted above, the mileage appears to have improved (I know a lot of people here recommend a VCM muzzler, but for now I'm just focused on getting things 'fixed') However, if the Autozone reader doesn't clear the codes, is it possible that I DO have a bad coil - the one that was on cylinder 2 and is now on cylinder 5? Or is it something else in the wiring, or maybe the ECM/PCM relation failure I haven't addressed yet? I'm inclined to just let it go as long as the check engine light doesn't come back on, but if I'm missing something easy...

fyi, I'm posting a picture of the spark plugs I pulled, in the order they were in the vehicle. Note plug #1 and #2 appear to be the most fouled, which I guess makes sense with the VCM system:

 

any updates? I am having the same ECM/PCM failure, modulator control unit power source low voltage and short in left front seat buckle, misfire on cylinder 5. I replaced all spark plugs and ignition coils and still same result.

 

any updates? I am having the same ECM/PCM failure, modulator control unit power source low voltage and short in left front seat buckle, misfire on cylinder 5. I replaced all spark plugs and ignition coils and still same result.