I got a Wheel Speed Sensor code when I did an Engine scan. The Code is C0215 (Rear Speed Sensor LH circuit). Issue is the wheel hub had to come off too because the wheel speed sensors come attached to the hub I replaced it and rescanned now I have two codes the same C0215 and C1241 which is Low or High Power Supply voltage( says to check battery and charging system) I recently replaced the Alternator because it needed to replaced. Haven’t replaced the battery The tool I used to scan is from Advance Auto Parts it’s a mobile 1000 Bluetooth scanner it also tells me the battery voltage is 12.4 and is orange colored. If I replace the battery I know the one code will go away but my question is it possible that if I fix the the one charging system code could it I fix the wheel speed sensor. If not I’m assuming the only thing to replace is the whee speed sensor harness? And where can I get the electronic power steering ECU? It goes in the dash behind the odometer. For the U0100 Code?

 

So how does the car perform? Is it starting OK? Does it idle, and drive fine? By your Adv. computer diagnostic test, they want you to buy over a grand worth of parts to "maybe" clear the codes. I'm not computer savy enuff to give you practical advice, so all I can say is good luck with it. You're gunna need it. Not sure why you scanned the eng. in the 1st place, but if you had a light on, or had-ta fix something mechanical, (if it were mine, and all drove fine), I would put a piece of black tape over the warning light, if it even has one.

 

Codes tell you a particular SYSTEM isn't fully functional, not that any particular part is bad. Don't rely on scanners as much as directly measuring parts. Pull out voltmeter and measure battery itself.

Only problem here is you might have a loose electrical connector. Might have some corrosion from water getting in. Nothing little sandpaper and OxGard can't fix.

It's like getting TPMS alert that tyre-pressure is low. Do you automatically replace all your wheels & tyres? Or do you pump them all up to find and replace one defective valve-stem? Testing by measuring gives you important data to find exact defective part in larger system.

Similarly, replacing perfectly good working sensor with brand-new perfectly good working sensor changes nothing. Because defect is elsewhere. To find that defect, you need to test and measure parts to come up with numbers. Then compare those numbers with standards given in manual to verify if part is indeed good or bad.

Scanners do not test individual parts, so you must replace entire system to catch that one defect. Also add replacing ECU and entire wiring harness to that list above because defect is somewhere between ECU and that sensor you replaced. Without testing, you must replace everything in between. Most of time, it's just a loose or corroded wiring connector.

 

I like that method Danno. Remove and replacing gains nothing but a more financially beneficial auto parts store. The problem for me, is finding the data to test each individual component. I swear there's a conspiracy that keeps the backyard mechanic from accessing this data. Even some factory manuals, (if you can find one) don't have this information, and if they do, they have their own codes you must break to figure it out. Very frustrating.

 

 

Thanks for info MR_LUV!!!

You can actually download factory manuals here: https://techinfo.toyota.com . This is what factory techs use at dealerships and it has all testing-procedures and measurement standards. Sign up for short-term $15 membership and download everything.

Even without manuals, you can get reference numbers. Now supply-voltage error is interesting. Again, gathering empirical data by actually measuring at battery-terminals would present useful info:

- Battery Voltage at rest
- Battery Voltage during cranking
- Battery Voltage with engine running

Doesn't matter if battery doesn't take and hold charge, it's only used for starting car. Unless new alternator is bad, we should be seeing +14v at battery with engine running where alternator provides 100% of all power-needs. Manual says 8-14v for supply-voltage is OK, so we're fine there. So 2 possibilities for error:

- Bad new Alternator
- Bad wiring causing voltage-drop to below 8v at ECU; this is more likely and would fool scanners as well since it's measuring at ECU, not battery.

As for sensor-error, there's another perfectly good wheel-speed sensor on the other side of car, he could've just measured impedance of good sensor and compare to "bad" one. Then use oscilloscope to compare output wave forms. Manual says should be +/- 2v peak-to-peak, but that's not as important as seeing that left sensor is same as right sensor.

In process of actually measuring sensors, he would've noticed that sensor-to-harness connector is corroded. There's rubber seal where sensor plugs into harness and this seal degrades over time, allowing water in to corrode connector. Simple enough to clean with some sandpaper and OxGard and re-seal with silicone when re-assembling. No need to buy any new parts because sensor and harness were perfectly fine!

BTW - this kind of maintenance is normal routine on motorbikes, they typically use bare-brass uncoated terminals in unsealed connectors. Requires disassembly and sanding/cleaning every 10-yrs or so.