P 0500 code. . . FIXED ! ! !

[bluemax229]

SURELY SOMEONE HERE HAS HAD THIS PROBLEM??

2013 Fiesta SE w/DPS6 transmission. Instrument panel lit up with the following icons: traction control OFF, traction control ENGAGED, ABS, low fuel (gas pump), check engine, and hill brake assist (or something like that?). Other symptoms . . . NO CRUISE CONTROL, ODOMETER is BLANK, stayed in 1st gear and WOULD NOT SHIFT, at least for awhile?

OBD2 reader says "P 0500." "INPUT SHAFT SPEED SENSOR "A". I replaced the gray sensor on the side of the transmission. No change. ANY IDEAS??? Thank you in advance!

 

[Handy Andy]

Did you happen to check the Connector?

You may need to locate it's pins and probe them to check for signal power and return (Ground) - usually this doesn't fail - or at least often.

I'm thinking a power fault - bad connection - your dash lit up...

That "pause" is a step in calibration - so it can find the Gears again.

 

[bluemax229]

Did you happen to check the Connector?

You may need to locate it's pins and probe them to check for signal power and return (Ground) - usually this doesn't fail - or at least often

I had to remove the battery and the battery tray to get to the sensor, so I couldn't probe the connector pins. I guess I could connect the battery with jumper cables and then probe the pins?

 

[Handy Andy]

Refer back to where the sensor connects - do you have the original sensor still?

Reason - if a failure in the harness - both sensors won't be able to send the right signal. So the system never restores itself.

So when I see a light up dash while I drive, that means a power fault - more than likely at the Alternator - a sending unit for speed is a simple interrupter - a Hall effect device so it's not going to pop the wires or send the battery into the tanks - something else caused the surge and may have damaged the sensor, but to have two sensors go bad - usually the one sensor replaced fixes the system and you let it recover by letting it initialize (the Idle learn and drive method) so it can find the shift points and gears by feel in the output sensor - so the input sensor "fail" may indicate another type of problem where there is a mechanical failure in the housing that sensor goes into. That means the transmission and the Clutch/Actuators and that whole area is suspect as to having a major failure and it needs to have the engine and transmission pulled apart and find the fault.

In many cases the dirt debris and parts of the clutch pack media - all collect in and around the sensors and any fixed spot - so that fault you can't seem to clear just might be a housing that got full of clutch media and so it affects the sensor to a point that it can't "see" so it sends the code until someone cleans out the housing. You get the same result using the next sensor and so-on and so-on.

 

[Handy Andy]

Refer back to where the sensor connects - do you have the original sensor still?

Reason - if a failure in the harness - both sensors won't be able to send the right signal. So the system never restores itself.

So when I see a light up dash while I drive, that means a power fault - more than likely at the Alternator - a sending unit for speed is a simple interrupter - a Hall effect device so it's not going to pop the wires or send the battery into the tanks - something else caused the surge and may have damaged the sensor, but to have two sensors go bad - usually the one sensor replaced fixes the system and you let it recover by letting it initialize (the Idle learn and drive method) so it can find the shift points and gears by feel in the output sensor - so the input sensor "fail" may indicate another type of problem where there is a mechanical failure in the housing that sensor goes into. That means the transmission and the Clutch/Actuators and that whole area is suspect as to having a major failure and it needs to have the engine and transmission pulled apart and find the fault.

In many cases the dirt debris and parts of the clutch pack media - all collect in and around the sensors and any fixed spot - so that fault you can't seem to clear just might be a housing that got full of clutch media and so it affects the sensor to a point that it can't "see" so it sends the code until someone cleans out the housing. You get the same result using the next sensor and so-on and so-on.

 

[bluemax229]

I looked back at the exact description from my BlueDriver OBD2 code reader.
"P0500 - VEHICLE SPEED SENSOR "A" CIRCUIT." There are three speed sensors on the transmission housing. Through my research, two of them are input sensors. . . a light gray one and a black one, mounted very close together. The other one is mounted lower, and is easy to get to from underneath. It is BLACK, and the has a "step" in the probe part. This is the OUTPUT sensor.

I already replaced the light gray input sensor with no change. I have ordered the other two sensors and will replace them as well. If that fails, I will thoroughly check the wiring between the sensor(s) and the PCM.

 

[bluemax229]

I am writing this for anyone with the same problem that is as frustrated as I was. The punch line is that the problem has been FIXED, and it ended up being fairly simple. No bad ABS sensor(s), no bad wiring, no bad ABS module. . .

I learned something about OBD2 readers. The codes they detect can be very, very generalized, and still leave you with many suspect things to check. The P0500 code and its explanation, " VEHICLE SPEED SENSOR "A" CIRCUIT" actually lead me down the wrong path. My Blue Driver OBD2 eventually did produce a more helpful code, which was "LEFT FRONT WHEEL SPEED SENSOR: SIGNAL INVALID." I switched ABS sensors, left to right, right to left. The code did not change. To me, that meant that all the wiring from the ABS sensor upstream was okay.

While all this is going on, I kept thinking back to the fact that about 6 weeks ago, I replaced both hubs and front wheel bearings? The car had been trouble free since then, which lead me to believe it was nothing caused by that repair. WRONG!

Out of ideas, and without any more sophisticated testing equipment, I admitted defeat and paid the local Ford garage their $100 diagnostic fee, with instructions that I would do the repair. The answer came quickly. The technician reported that both front ABS wheel sensors were giving sporadic readings. He was able to spray brake parts cleaner into the right side sensor and basically clear it up. Not so much with the left one. His advise was to take everything apart and clean it with wire brush and brake parts cleaner, as some of the grit and rust was laying on the surface of the tone ring (the magnetized strip attached to the inside of the wheel bearing that is "read" by the ABD sensor). There is a reason why they say to NOT use any lubricant when pressing in wheel bearings with magnetic tone rings! That lubricant had attracted the grit and rust particles, which interfered with the ability of the sensor to read the imbedded magnets.

So I once again replaced the wheel bearings, this time with Ford parts (made in Japan, not China). The tone rings are pink, which helps you not press them in the wrong way. I put it all back together and just like that, every single code went away.

If I had a professional scanning tool, and could have looked at an oscilloscope graph of each ABS sensor, I could have diagnosed this myself. I have since fixed that problem by purchasing a X-TOOL D7S. Hoping it is the best money I ever spent!

 

[Handy Andy]

So I once again replaced the wheel bearings, this time with Ford parts (made in Japan, not China). The tone rings are pink, which helps you not press them in the wrong way. I put it all back together and just like that, every single code went away.

If I had a professional scanning tool, and could have looked at an oscilloscope graph of each ABS sensor, I could have diagnosed this myself. I have since fixed that problem by purchasing a X-TOOL D7S. Hoping it is the best money I ever spent!

Wow - the "Speed Sensor A" can also include the Speed sensors on ALL the wheels.

I don't think it will break the Internet, but this is good to know. for several reasons.

Dirt in the sensor, the Ring and the tone it produces - all affect this - and not just at the transmission either.

Nice detective work on getting to the bottom of the problem. - thanks for getting back with us on this.