P0500 OBD-II error/freakout - tire size related (mismatched sizes)?

Attachment 21616
(Different front/rear tire size issue?)

So the car just threw a p0500 error multiple times (VSS related, maybe).

When that happens, the cluster lights up like a freaking Christmas tree!

- check engine
- brake problem (aka parking brake light)
- ABS
- stability control & traction control
- speedometer stops working (drops to zero)
- EPS / power steering

The last one is interesting: the car actually disabled the power steering while under way. Good thing I have massive upper body strength to wrestle an unassisted Mirage to safety!

Restarting the car fixes the EPS / speedo issue... until the dash lights up again.

I'm wondering if it's tire size related. I recenty changed to different sizes on the front & rear (larger than stock up front for lower engine RPM). 185/65r15 vs. stock 165/65r14.

That said, I had done the same thing to Mirage #2 with NO PROBLEMS. Except the rears were 175/70r14, not stock 165's, which was a smaller % difference between F&R.

Investigating further...

When you review the actual Mitsubishi Mirage specific DTC codes, P0500 error message is: EXCEEDS PARAMETERS FOR REAR WINGAGE.

the code says vehicle speed sensor system

function:

the vehicle speed sensor converts the vehicle speed to voltage and then input it into the Eng-Ecu.


Probable Cause:

vehicle speed sensor
harness
eng-ecu

this is based on that code but it says there is no failsafe and you experienced a lot of fail safe maybe theres more code?

i replaced my 14" rim to 15" and ddnt experience that problem.

But all your tires were all the same size. (I assume.)

What I'm wondering is if the computer doesn't like to see wheel RPM differences exceeding a certain threshold.

Does the manual trans even have a conventional VSS, or does it use ABS sensors?

I just put the 175's on the back (copying the same setup as Mirage #2), and no error came up after a short-ish test drive.

I may also trim off some of the rear Kammback. :)

Quote:

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Originally Posted by MetroMPG

I'm wondering if it's tire size related. I recenty changed to different sizes on the front & rear (larger than stock up front for lower engine RPM). 185/65r15 vs. stock 165/65r14.

That said, I had done the same thing to Mirage #2 with NO PROBLEMS. Except the rears were 175/70r14, not stock 165's. So, a smaller % difference between F&R.

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165/65r14 (22.4")
175/70r14 (23.6")
185/65r15 (24.5")

Outside diameter variance between 185/65r15 & 175/70r14 is 3.8%.

Outside diameter variance between 185/65r15 & 165/65r14 is 9.4%.

Does different size tires in the front & rear make a difference (impact ABS)?

I think your experiment with different size tires may have answered this question for all of us.

A quote from a mechanic on this topic -

"Most ABS systems, along with the ECU that controls it, have a built in operating range that can accommodate varying tire sizes and wheel speeds, so as long as you don't go "monster truck" size, and you keep relatively close sizes on all four corners, the ABS system can handle it."
Dec 28, 2017

Quote:

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Originally Posted by MetroMPG

I may also trim off some of the rear Kammback. :)

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Why? It looks like a cowbell. And we need more cowbell.

It’s probably why you got all those fault indicators. Lack Of Cowbell must be one of those hidden error codes. It clearly affects all those systems you listed.

Quote:

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Originally Posted by 7milesout

When you review the actual Mitsubishi Mirage specific DTC codes, P0500 error message is: EXCEEDS PARAMETERS FOR REAR WINGAGE.

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The rear WIND(AGE) is so efficient the computer can't even understand it.

Hey Metro, I'm sure you already thought of this, but do you have something plugged into your OBD connecter?? One of the insurance tracker things or something???

I've run cars on the lift(only front wheels turning(obviously)) and it throws abs and trac control lights. I don't recall what the codes were. Turning the trac control off seemed to make it less pissy.

I had a sonic that acted similar. Relatively recently. It had an obdII gps in it for the last 5 years, never had a problem til about a month ago. One day it quit tracking properly then out of the blue killed the power steering, lost the speedometer and lit up most of the warning lights on the dash. Had the car towed back to the shop and it worked fine once the tow truck got there. It was totally at random. I had the gps dongle reflashed via magic pixies and it's been fine since.

Funny: I've gotten the ABS/Traction control freakout when I was idling the car in gear on jack stands to "machine" rusty rotors. But that problem clears itself the next time you drive the car. Like within half a block.

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I've had a ScanGauge-II plugged into this car without issue, as I did in Mirage #1 and #2. That said, the first thing I did when I saw the dash light up was yank it out after clearing the code. And then problem returned multiple times with it disconnected.

That said, it was really hot yesterday, and the SG was sitting on the dash in direct sun. That made me wonder if it got hot enough to somehow malfunction and piss off OBD-II. But I kinda doubt it. The SG looked to be working normally.

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I'm taking the car on a ~120 km round trip today with the wheel/tire combo from Mirage #2 installed (which caused zero ECM freakouts, and which appeared to be OK last night in a brief test drive). If it's uneventful, I'll swap the smaller rear tires back on when I get home and see if that triggers it again. If it does, then I have the definitive answer.