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How to fix a bad Angle Sensor

235K views 28 replies 23 participants last post by  Davidtorresmx 
#1 · (Edited by Moderator)
Sorry for the pic layout, but I couldn't figure out how to add a pic after each step. So the numbers after each step go to the pics in order from left to right.

This is some very helpful info I learned about angle sensors and the fact that probably a big majority of them can possibly be fixed instead of the need to be replaced. All they consist of is a pair of contact brushes mounted to a small spring-loaded wheel that turns along an electrically conductive strip that varies in resistance from one to the other. Unless serious damage has occurred to the brushes or the strip(physical damage, excessive wear to the brush tips or resistance strip), there's really not much that can mechanically go wrong with them. Over time, the o-ring that seals the sensor to the engine case can dry out and shrink allowing water to enter the sensor housing through a couple of small holes in the backplate and around the sensor shaft. This can lead to a build-up of oxidation on the contacts which in turn creates more resistance or can completely disrupt the connection between the contact points, both of which will give false readings which produce error codes and ultimately lead to the sensor being trashed and replaced.

All you need is a few simple tools and a DMM (digital multimeter). An analog volt/ohm meter can be used but isn't as accurate as a digital meter so it's possible to false readings with an analog meter.

Tools:
  • X-acto or similar razor blade
  • Needle nose pliers or tweezers
  • Ultra fine needle files or some very fine grit sand paper
  • Dielectric grease
  • Electronic contact cleaner (not necessary, but recommended)
  • Super glue
  • DMM
  • Silicone (I use Permatex Ultra Black)

First off, test to confirm the sensor is out of spec. Download a service manual for your model which will have the specifications for the sensor and the steps for testing. Once it is determined that the sensor is faulty, it's time to grab your razor and cut it open. First, use the razor to make a couple of marks on the sensor housing and backplate so you'll know where to position the plate during reassembly. This is necessary cause the spring inside is slightly torqued which allows the brush wheel to return to it's rest state. To do this, look on the engine side of the sensor and you'll see a small thin ring around the outside of the backplate. Take your razor and slide it under this lip and cut all the way around, breaking the lip off as you go.
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Next, carefully pull the backplate off, if it hasn't already popped out (there is a spring underneath so be ready). Now, use extra care and remove the brush attachment. Be very careful not to damage the tips of the contact brushes which are very finely stranded metal and can bend or break off if not careful.
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Next, using needle nose pliers or a set of tweezers, remove the resistance strip retaining clip then carefully remove the resistance strip itself. The strip will have 3 small contact points at one end, which in most cases, get oxidized and corroded due to moisture. Also, the contact pins which remain in the sensor housing will also get oxidized and corroded.

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Once completely disassembled, carefully clean the contacts on the sensor housing using needle file or sandpaper. If you have some electronics cleaner, spray them off once done. Now, you must be EXTRA CAREFUL when cleaning the contact points on the resistance strip. These contacts are very very VERY thin strips of metal and can be easily damaged. My advise is not to use sandpaper on these. I used the tip of a needle file and very gently scraped till the contact was shiny then washed with contact cleaner.

Once everything is cleaned, apply a small dab of dielectric grease to the center of the sensor housing where the brush attachment sits. This will make the brush wheel turn easier and also help repel moisture. Insert the brush wheel paying attention not to damage the brush tips. Reinstall the spring as it came out (each end of the spring has a different bend and will only go in one way which will be obvious) and place the backplate onto the spring, and squeeze back together into the housing realigning the backplate with the marks you made in the beginning. I used a couple small clamps the hold it together as I applied a couple drops of super glue. Once the glue is dry, remove the clamps and apply glue all the way around and allow to completely dry. Once dry, use your meter to verify that all your work has paid off by testing again using the procedures in the service manual.
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Reinstall sensor into the sensor bracket. I applied a little bit of Permatex Ultra Black silicone on top of the o-ring to ensure a good water tight seal to the engine case. Reinstall the sensor to the case, being sure to preload before installing the bolts, and torque to specs. Apply a dab of dielectric grease to the plug and reattach the harness. If done correctly and considering that the sensor was salvageable, you just saved yourself $50-$100 bucks. I hope this helps someone in the future. I know it fixed my problem and saved me money that I can use on something more desirable.
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#3 ·
Great write up --- Thanks for posting.
 
#5 ·
Has anyone studied the feasibility of making the rancher system a "closed loop" style with an oxygen sensor? Ive been toying around with it, but its been 20 years since I went to electronics school and I dont remember half of what I learned. Im trying to study it, but its slow going. Anyone have an inside track?
 
#7 · (Edited by Moderator)
the only way that would work is POSSIBLY...and I stress possibly, with the consideration that someone that knows the layout and operation of the ECM on a fuel-injected model and it would strictly have to be a fuel-injected model. U could actually drill a hole in the header and weld in a bung and install a two-wire O2 sensor on a carburated model and wire it to an air/fuel ratio meter to tune to the desired 14.7:1 air/fuel ratio which I've done on several carb'ed vehicles for carb tuning purposes....but in the world of ATV's, it really wouldn't be practical as this ideally only benefits fuel economy, emissions, and with automobiles, power, which I would suspect wouldn't be worth the effort with an ATV.

As for a fuel-injected model, the ECM would have to be reconfigured to integrate the O2 readings with stuff like TP sensor, VSS sensors, air temperature, atmospheric pressure, etc. in my opinion, a two-wire O2 sensor could be used to tune in a carb for maximum efficiency but the end results wouldn't be worth the effort and money spent. Just my thoughts but still a great subject to discuss!!
 
#10 ·
I stand corrected. Everything I have been researching has showed the angle sensor to be this little metal shaft that cost $6 No where in the parts diagram on the honda oem site does it mention this black spring loaded sensor. They don't even show one. I've been so confused trying to figure out what everyone was talking about. Then I took the real sensor out and out popped that shaft. It all makes sense now. That sensor is 60$ for me.
 
#12 ·
Great info... Even though I have a 700xx, it also has a Bank Angle Sensor... It's a different shape, but I'd bet the procedure would be the same. I haven't had any issues with mine, but still good info.

roadkill
 
#13 · (Edited by Moderator)
The information in this post solved my issues so I want to say thanks!

This shifting issue has been driving me crazy for some time. I got hung up in the dark on the side of a mountain and decided to find the solution. My 350 FE has been shifting strange for a while, not going right into gear when you shift. Then getting stuck in gear and the blinking shift indicator requiring pulling out the tool to get to neutral- then shutting off the bike and waiting and restarting hoping the blinking stops.

I bought an angle sensor for 55 of eBay. Found the service manual link on this page, identified the location of the AS in the manual- general info, pages 1-26, 2-7, learned about the ES system 2-8, 2-9, went out and tore into and replaced the sensor. Tools= socket wrench with small extension and. Allen wrench - 45 minutes. Test ride = completely different bike slides into gear each shift. No blinking light!

Prior to finding this solution, I did some routine maintenance. My battery had a 60% charge. I filled the cells with acid and charged them to 100% and the frequency of the blinking light decreased. The battery charge has something to do with how the ES system operates. Reading the service manual, the entire system is operated by multiple electronic components and a control box.

Anyway thanks again. No getting stuck again- at least due to the shift issue.
 
#18 ·
Just a head up. The angle sensor cost $16.45 thru Honda East Toledo | For Sale Yamaha Suzuki Kawasaki Polaris Can-Am Sea-Doo Ski-Doo Arctic Cat Victory Kymco Aprilia Motorcycle ATV Side by Side Personal Watercraft Snowmobile Scooter 4x4 Utility Vehicle Generator Ohio Michigan Indiana. The part # is 38800-HPO-A11. There is a shipping fee of $11.99 which brings the total to $28.44. I have been buying parts from them for a few years now and their prices and service are unbeatable. Their prices are almost half what you will find at any dealer.
 
#19 ·
Hi Im new to this forum and not sure im posting in the right place but nonetheless need help i changed out the angle sensor on my rancher 400 and im trying to go thru the set up instructions I can get past the up down up but once i hit the throttle the N does not show up I can hear the shift motor kick on but it only stays on literally a second Any suggestions? Thanks
 
#20 ·
for what its worth, after replacing my fried shifter motor, i still had the blinking "--"

i wanted to try something simple before going to the dealer and buying another angle sensor...so....

i just took it off the atv, sprayed it with some compressed air and applied a light mist of wd-40 into it. i then made sure the sensor was able to rotate/preload. once it broke free i reinstalled it.

once it was all back together, i had reset the ECM (a critical step!!!), and then the atv started working perfectly again.

just wanted to share my experience with the angle sensor.

cheers
 
#22 · (Edited)
I just went ahead and ordered a new one. What does it mean in write up to "preload before installing the bolts". Anything to keep in mind when removing /installing it? Once done, is there any procedure to reset computer??(Disconnect battery, turn key, etc). I read this from a poster to thread but didn't explain procedure

once it was all back together, i had reset the ECM (a critical step!!!)
 
#24 ·
when he said pre-set ( pre-load ) ?..what he was telling everyone, what you do is..put the angle sensor on the shaft where the two bolt holes on the sensor are about at 9 and 3, then turn the sensor until the bolt holes line up. when you do this..your pre-setting the sensor ( pre-loading the spring inside )..this is what he meant. as for re-setting the ecu ?..your service manual tells you how to do this.
 
#25 ·
Great write up. I completed all the steps listed but trying to reset the ECM is not working for me. My service manual says hold both up and down buttons and turn key on, then release and press up, down, up, then instead of N it will show --, then Im supposed to open throttle to full and fully close and the indicator should read N again. No matter what I do I cant get it to read N again. When Im not trying to reset the error code 6 reads on the display(6 short flashes of --). So that means angle sensor problem. I dunno what to do, dont want to bring it in and spend lots of $$, just bought this thing in the fall. Been trying to fix this for weeks. Any suggestions on how to reset the ecm before I light the thing on fire?
 
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