Hello all, I've had this car for a little over a year, 2005 6MT with 84k miles 2nd owner. This code has been on for the entirety of my ownership.
The only code I have whatsoever is the 64-1 Sensor Supply Voltage Failure code. Just this one code. ABS still works. Neutral safety position learning procedure doesn't change anything, needs to have code 84-1 to perform it seems anywho. Tried the memorization procedure function through the scanner and also the procedure Acura uses in the FSM.

I've followed the 04-07 factory service manual troubleshooting steps and I don't have much of an idea to move forward except replacing the VSA control unit.
It tells me to clear the code (but it's permanent) check for voltage (1+ volts) at the big VSA connector at pin 35 and ground, and also continuity between pin 35 and ground.
I read way less than 1V, but I do read continuity at 60.9k ohm. The next step if continuity is found is to "repair short to ground in the wire between the VSA control unit and yaw rate sensor and steering angle sensor."

I don't entirely understand this next step, and if I were to understand it I'd have no clue on how to find this "short to ground" in an entire loom. Could the VSA unit, yaw rate unit, or the steering angle sensor themselves be the culprit? The VSA chassis ground G203 connector seems 100% in tact but all else I have no clue. Nothing seems immediately damaged.

With my scanner I can't connect to the steering angle sensor and in the VSA live data the angle always displays as "4 degrees", so I don't know if this could be the cause.
Any help is welcomed!

 

Well 60.9k is not considered a short. Too bad that I can't find any info on that code except for this procedure that you posted.

You didn't forget to disconnect the VSA connector before taking the measurement?

Measure the #35 to ground with engine running and connector connected. I would expect it to have 5V as it's sensor power. Let me know. Also measure #33 to ground or to power. In theory #33 should be a sensor ground.

 

Yeah so I cleared the code, unplugged the connector and then started the car and took measurements. But yeah both measurements were taken on pin 35. I will check pin 33 as well using the same directions!

 

Well pin #33 shouldn't be important. Just briefly check it if it's grounded when running.

My theory is that some sensor is shorting the voltage supply (pin #35) and that's why the code pops up. To check the theory, you need to measure pin #35 to ground when connected and engine running.

 

TSB procedure says to check it with the connector unplugged with the car on and to check for under 1V so that was easy to do. Excuse my ignorance but how do I check that same pin/wire with it plugged in? And then what reading should I be looking for when checking it plugged in?

 

Either pierce the wire or use a pin or needle to back probe the connector. Since connector is kinda enclosed you need to get creative. I would probably cut open the plastic tube covering the wires. Shouldn't be too many red wires there - there should be three actually. Pierce one and use your multimeter to probe pin #35 and that wire while uplugged. If you have 0 Ohm you found correct red wire. 33% of chance.

Or you can get the reading at the steering wheel angle sensor. Since you have a manual finding the correct wire at the sensor should be easy. Just measure the voltage while running and everything connected.

And I don't know what reading you should expect. I'm betting the system works at 5V as that is common voltage for the sensors. Depending on what you find we will need to figure out if that makes sense.

 

NEVER FRONT PROBE A CONNECTOR.

Front probing can cause the terminals to spread and you'll be chasing your tail. Get yourself some T-pins so you can back probe the connectors.

Also, visual inspection is very important. Check for any corrosion at the connectors, bent pins at the connector, any chaffing of the harnesses, etc. Check for blown fuses to the VSA system.

Assuming you've done that:

1. Back probe Pin #35 and measure volts with reference to battery ground.
2. Turn key to ON position.
3. Should be ~5V.
   1. If good, jump to step 5.
4. If less than 1V,
   1. Measure voltage at Pin #35 with reference to battery positive.
   2. If you measure battery voltage, then you have a short to ground.
   3. Do a visual inspection and a wiggle test to help pin point the ground.
   4. If you still measured 0V, then you probably do not have 5V output from the VSA unit.
      1. You will need to verify that the VSA is receiving all the powers and grounds.
      2. If it has them, then you probably have a bad VSA unit.
5. Test if VSA sensor ground is good at Pin #33
   1. Back probe pin #33 and measure voltage with reference to battery positive.
   2. Should be battery voltage.
   3. If not, then you have a bad ground in the VSA unit.
6. If both output sensor ground and 5V are good at the VSA unit, then you will need to measure the 5V and grounds at the sensors.
   1. If you have both 5V and ground at both sensors, then the sensors are bad.
   2. If you do not have 5V and/or ground at both sensors, then you have an open.

 

About point #4. My theory is that if there is below 5V then maybe one of sensors is shorted.
That would explain why there is a code about power failure. And since he did measure resistance to ground with connector disconnected, ground from VSA to sensors was also disconnected, so this test wouldn't pick it up.

If there is below 5V then disconnecting fault sensor would bring the voltage back to 5V. If disconnecting them both doesn't bring it back to 5V then VSA is faulty or there is some other kind of short.

Nice that you found the table what we should expect on pin #35. No more guessing.

 

Maybe.

But I doubt that a shorted sensor will cause the 5V output to be pulled significantly down to be 0.5V < Output < 4.8V

If you look at the wiring diagram, the steering angle sensor and the yaw sensor are connected in parallel. If one of them has a lowered resistance then the 5V would remain. If one sensor was completely shorted with a direct path to ground then the 5V from the VSA will be pulled to ground and you'll have 0V. The over-current on the 5V output could fry that circuitry and then you'll have bad VSA unit.

You could also have both sensors with less than nominal resistance, which will cause a higher current draw from the VSA unit but the 5V will still be there unless it reaches it's current limit.

 

Forgot to add the stuff in red.

 

Have you tried just replacing the battery?

 

If that was battery issue I'm giving up

 

Yeah. LOL

 

just practicing the KISS methodology of troubleshooting

 

Thank you so much for the info, I'll get right to this. Though I do have a question or two.
1. #5 "VSA sensor" You're talking the VSA modulator unit correct?
2. #6 (all steps), by "sensors" how do you mean? To back pin the pins for the Yaw rate and the steering angle sensor... Or am I needing to be looking elsewhere?

Here's a pic of the back end of the VSA modulator connector (connector 47P). It seems quite difficult to back pin with just a normal T pin so I might have to get creative as these connections are weatherproof ones but I will try nonetheless. Would a regular T pin fit normally past that rubber seal? Visually everything seems 100% and nothing immediately outstanding. Pin 35 is the full red wire, pin 33 is a yellow/blk wire.

I could also try changing the battery but as it stands it has good sitting voltage and good CCAs. Will keep in mind though, while snooping around for 64-1 threads I saw somehow report where a battery magically fixed some VSA issues lol.

 

1. Yes, "the VSA modulator unit"
2. Yes, "To back pin the pins for the Yaw rate and the steering angle sensor."

Just stick it past the rubber seal, or like I wrote stick it right through insulation somewhere at the wire, where it would be easy to put a piece of insulating tape when you're done.

 

Here are my readings:
Pin 33 to battery ground 0v. To battery positive 12v. (SGND)
Pin 34 to ground 0v. (YAW)
Pin 35 to battery ground 30mA (0V?). To battery positive 12v. (SVCC)
Pin 37 to ground 0v. (GLAT)
Pin 38 to ground 12v (IG1)
Pin 43 to ground 4.68v (don't have anyone to turn wheel slowly so this it stationary voltage). (STR-B)

 

How you got 30mA? If you meant mV then:

Disconnect the steering angle sensor and recheck the #35. If still 0V either cut the wire where it's easy to fix, or disconnect the yaw sensor. No idea how to get to it, so wire might be easier, if you go for the sensor then leave both of them off.

After disconnecting each sensor clear the codes and cycle the key before rechecking the #35.

Also measure resistance of #33 to #35. Doesn't matter if connected to VSA, but leave connections to both sensors.

 

Yes yes, meant mV!
Looking in the FSM it's super unclear how to even get to the SAS, possibly by taking the steering wheel off something. On the replacement guide the diagram doesn't seem to show any plug for the actual assembly.
I'll look further into it. Maybe all that's required is to take off the plastic steering wheel surround.
And yes the YAW sensor is about ~10 inches forward of the shifter inside the dash assembly. It's a tough cookie, FSM makes it seem like a piece of cake!

 

 

My troubleshooting steps are ment to be done with everything plugged in.
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"VSA sensor ground" is the ground provided by the VSA unit to the steering angle and yaw sensor.

I mean, if the VSA pin# 35 has 5V and pin# 33 has ground then you will need go to the sensors and test if they are getting the 5V and ground.


You should be able to backprobe.

https://sites.google.com/site/miatad...ing/images.jpg


I would be careful about piercing the wires if OP has never done it before. He could easily over do it and create more problems by cutting too many strands.

 

Were these measurements taken with the connector plugged in and the ignition ON?

Pin #35 does not look right.

Make sure the connector is plugged in and key is ON. Be careful when you backprobe and avoid getting the T-pin touch ground because you can cause a short.

 

All measurements were done with with everything plugged in, with the VSA connector plugged in, with key ON. I'm very certain I back probed the wires correctly as well.
I'm noticing the battery drains generally quickly when the key is ON. Battery tests fine and holds voltage fine but it drops voltage on a load with the engine off.

 

Car can drain a lot of power when key is in ON position. 5-8A easy.

Any luck with measurements when sensors are disconnected?

 

Well I put up with this issue for almost 3 years. I just sold the car last month in 08/2022, and right before I sold it I managed to find a 05-06 VSA Pump (motor, etc) from LKQ online and installed it, was originally from a 06 6MT TL. Bled the brakes with a power bleeder and it actually fixed ALL of my codes. IIRC I had a few VSA codes and a Yaw rate sensor code. The used VSA module solved all codes, the VSA button worked, and the TL's traction control light worked normally when spinning. This is just a quick update for those who may have this issue in the future.

I know I couldn't find much on this VSA issue when I had it at first, and totally uncharacteristic for a car that had well under 100k miles.

 

@Striball Thanks for the update!

It looks like you were very close to solving it back then when you measured 0V at Pin #35, which means the VSA unit had internal fault at the sensor 5V output.