ABS Fault Code 16

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chrisshara
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ABS Fault Code 16

Post by chrisshara » Thu Dec 20, 2012 2:27 am

I have a 1994 Legacy GT that is triggering fault code 16 in the ABS control module. I read a PDF online that says my car could have a Bosch ABS system, a Nippon 2E system or a plain Nippon system. I have determined that I have a Nippon system and I have the LED on the control unit, so I'm not sure if I have the "2E" or non-"2E" system. I also have gathered that fault code 16 has to do with either a faulty control module, faulty Yaw rate sensor, or a wiring issue. Since I have no wiring schematics and replacing a control module is very expensive, I elected to start by replacing the Yaw rate sensor "G-sensor." I called Subaru, they first told me my car did not have the Yaw rate sensor, and then they gave me a price of $222.76 and told me it was discontinued and none were available, and that I had to track a used Yaw rate sensor down. Subaru provided me with the part number. I searched online by the part number that Subaru provided, for a used Yaw rate sensor. I found a used yaw rate sensor on ebaY, and it matched the part number that Subaru provided. The part arrived and it was a Bosch Yaw rate sensor, which does me no good since I have a Nippon system.

So now I am very confused. I am wondering is my Nippon system even uses a Yaw rate sensor? Is the Yaw rate sensor inside of the ABS control module on this Nippon System? Did Subaru provide me with the incorrect part number for the Yaw rate sensor ?

I thought the Yaw rate sensor was located smack dab in the middle of the fire wall. I am seeing a sensor in this location on my vehicle. Am I looking at a Yaw rate sensor ? Or could it be another sensor ? The sensor I am seeing in the middle of my fire wall has (5) wires going to it.

Any insight is greatly appreciated.
94 Legacy GT
95 BMW (E36) 325ic
81 BMW (E12) 528i
04 Outback
02 Acura TL Type S

Legacy777
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Re: ABS Fault Code 16

Post by Legacy777 » Thu Dec 20, 2012 7:25 pm

Your ABS system does have a G sensor. However it is not located on the firewall, that is the igniter. The G sensor is located on the top side of the passenger frame rail below the AC receiver drier.

The G sensor is the same sensor, regardless of whether you have the Nippon or Bosch ABS system. The part # is the same for both systems, 26740AA040.

Just unbolt the old one, disconnect the electrical sensor, and put the new one in.
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
1997 Impreza OBS

If you need to get a hold of me please email me rather then pm

chrisshara
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Re: ABS Fault Code 16

Post by chrisshara » Fri Dec 21, 2012 12:24 am

Josh, thanks yet again.

I did locate it this morning. I read online that the ignitor was supposedly the G-sensor, FAIL. Then the guy whom I bought my used G-sensor from told me it was on the passenger strut tower; which drove me up a wall because we know it's not located there either.

Then the seller of the G-sensor told me that the repair instructions to replace the G-sensor stated to flip a switch for the G-sensor, located in the right front wheel arch, before disconnecting the G-sensor. I could not find this switch, so I just disconnected the battery before disconnecting the G-sensor.

....Both my 6mm. bolts broke that mount the G-sensor to the passenger frame rail. LOL I sprayed them with PB Blaster and let that soak in for 20 minutes. Grabbed the stud with a pair of vice grips and snapped the stud flush. Cleaned off the PB Blaster and tomorrow I'll go at these studs with the heat wrench. I'll keep everyone posted.
94 Legacy GT
95 BMW (E36) 325ic
81 BMW (E12) 528i
04 Outback
02 Acura TL Type S

Someperson
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Re: ABS Fault Code 16

Post by Someperson » Fri Dec 21, 2012 1:15 am

that's a bitch and a half...
Blue 94GT dead and steadily parting out.
Silver 93 Fwd N/A sedan undergoing repairs
93 Winestone TW project
92 SS scrapped by my landlord...

chrisshara
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Re: ABS Fault Code 16

Post by chrisshara » Fri Dec 21, 2012 2:33 am

LOL. That is small compared to the headaches I deal with at BMW. Have you ever heard of removing an engine "just" to "try" to diagnose a cylinder #7 misfire ? Have to remove the engine just to remove the cylinder head.

How about replacing a body harness to repair a LIN Bus fault for an "All-Round Camera," which is a reversing camera that has (3) cameras in the system. (1) camera on the tail gate and cameras underneath each of the side view mirrors. These are 40 to 60 hour labor operations.

I've also replaced an N73 12 cylinder engine, because it had no oil pressure after a car accident. The oil pump must have broke in the accident. No oil pressure equals 12 cylinder misfire because the variable cam timing had no oil pressure. Dropped the oil pan and all metal shaving in the pan.

This N73 engine has (4) engine harnesses: Inputs harness, Outputs harness, Fuel Injector harness, and Main power harness. warranty pays 55 hours to replace this engine.

Jobs of this nature are a bitch and a half. Broken bolts is cake. ...As long as there is a torch handy.
94 Legacy GT
95 BMW (E36) 325ic
81 BMW (E12) 528i
04 Outback
02 Acura TL Type S

mike-tracy
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Re: ABS Fault Code 16

Post by mike-tracy » Fri Dec 21, 2012 7:14 am

This reminds me, when I worked in a junkyard there was a master list of mercury switches in cars. The abs 5mt 1st gens were about the only subies that we had on that list. These had to be pulled before crushing the cars.

So don't go all crazy and crush your old sensor and lick the contents, lol.
1992 Legacy SS 5mt, build in progress
Josh Colombo wrote:
Mon Jan 14, 2002 10:23 am
Wait....I'm confused now.

chrisshara
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Re: ABS Fault Code 16

Post by chrisshara » Fri Dec 21, 2012 1:23 pm

Where is the mercury switch on the First Gen Legacy ? Are you saying that the Yaw Rate Sensor essentially is another name for a Mercury Switch ?

No worries with my old sensor. I won't be licking it. I won't go crazy with my sensor. Work drives me crazy enough. So when I'm out of work I try to settle down.

Mike, thanks for the heads up of the poisonous content, internal to the Yaw Rate Sensors.
94 Legacy GT
95 BMW (E36) 325ic
81 BMW (E12) 528i
04 Outback
02 Acura TL Type S

chrisshara
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Re: ABS Fault Code 16

Post by chrisshara » Sat Dec 29, 2012 1:43 am

Well, I finally had a break in the BMW action to use our shop torch to extract the broken 6mm. bolt studs that held the original Yaw rate sensor / G-sensor to the frame rail. The studs were a piece of cake to get out. The hardest part was coordinating a time slot with my shop foreman to bring my car into the shop, since down time is hard to come by at our facility.

Now that I have the sensor installed. I am experiencing the same issue with no change. I always felt that I might be dealing with an ABS control module that is malfunctioning. But, I wanted to try to the more affordable part first, and the part that seemed more prone to failure; as the Yaw rate sensor is exposed to the elements.

Nevertheless, I am now in need of a known good ABS computer. Does anyone either have one or know how I can repair mine ?

Maybe I should explain what I am experiencing, before the ABS MIL comes on. When my ABS first began to malfunction, teh ABS modulator would pulse my brake pedal only at traffic lights while at a complete stop. ...These days my ABS modulator will pulse my brake pedal even when the car is coming to a normal / safe stop. The very first time I touch my brake pedal, the ABS will malfunction and the ABS MIL will come right on. The ABS computer recognizes the malfunction very promptly these days. In the distant past, when the ABS would activate at stop lights, the MIL would not come on as often.
94 Legacy GT
95 BMW (E36) 325ic
81 BMW (E12) 528i
04 Outback
02 Acura TL Type S

Legacy777
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Re: ABS Fault Code 16

Post by Legacy777 » Wed Jan 02, 2013 7:26 pm

Since replacing the G sensor, have you "reset" the ABS computer and then checked it for stored codes once the ABS MIL comes on again? If not, I'd suggest doing that first to verify what code is being tripped.
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
1997 Impreza OBS

If you need to get a hold of me please email me rather then pm

chrisshara
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Re: ABS Fault Code 16

Post by chrisshara » Thu Jan 03, 2013 1:07 am

My system has the LED on the ABS control module. The control module is under the passenger seat on my vehicle. My vehicle does not have the jumper connector in the drivers side kick panel (at least not that I could determine).I am led to believe that my ABS system does not store codes long term, based on a PDF I found online. The PDF says my system does not have "Long Term Memory," or "Select Monitor."

I have the Nippon system. Not the ABS-2E.

I appreciate the help.
94 Legacy GT
95 BMW (E36) 325ic
81 BMW (E12) 528i
04 Outback
02 Acura TL Type S

Legacy777
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Re: ABS Fault Code 16

Post by Legacy777 » Thu Jan 03, 2013 7:01 pm

So what trouble code comes up, is it still the same code 16? Forgive me if you mentioned this above, but have you verified and checked the resistance of all the wires from the G sensor to the ABS ECU?

Have you tried pulling the battery cable for an hour or so....just for kicks and giggles.
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
1997 Impreza OBS

If you need to get a hold of me please email me rather then pm

chrisshara
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Re: ABS Fault Code 16

Post by chrisshara » Sun Jan 06, 2013 7:46 pm

Josh,

Same code returns 5 seconds after each time I start the engine. When I start the engine the ABS light is "off." Roll forward and the ABS light comes on at the first time I apply the brakes. Fault code 16 is the only fault triggered, and comes back every time. I have no ohmed the wires, as I do not have Subaru specs for these (2) wires.
94 Legacy GT
95 BMW (E36) 325ic
81 BMW (E12) 528i
04 Outback
02 Acura TL Type S

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Re: ABS Fault Code 16

Post by Legacy777 » Sun Jan 06, 2013 9:13 pm

You can always check the wires from the ABS unit to the G sensor for continuity to make sure the wiring is good. It should be zero ohms.
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
1997 Impreza OBS

If you need to get a hold of me please email me rather then pm

chrisshara
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Re: ABS Fault Code 16

Post by chrisshara » Mon Jan 07, 2013 2:34 am

Wiring has a degree of resistance. As long as there are terminals crimped onto the wiring there has to be a numerical value for the degree of resistance. Continuity checks have already been conducted. And yes, I have checked those wires for shorts to power and shorts to ground by way of checking continuity, or complete circuit, to power and ground. I thought you were asking me to measure the resistance in ohms. In that case, I do not have specs.
94 Legacy GT
95 BMW (E36) 325ic
81 BMW (E12) 528i
04 Outback
02 Acura TL Type S

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Re: ABS Fault Code 16

Post by Legacy777 » Mon Jan 07, 2013 4:34 am

Ok, I must have missed that in one of your previous posts.

I don't recall if you mentioned it, but does your Legacy have an automatic or manual transmission?

I just read over the 92-94 factory manual and it has an extra blurb in there regarding code 16.

"Faulty ABS control unit or G sensor or broken or shorted harness, or malfunctioning system or line unidentified by vehicle speed sensor fail-safe function."

I'm not sure how or if that helps or just muddies the water some more.

Out of curiosity, did you happen to check the resistance of the old and new G sensor. The FSM says it should read 550 - 670 ohms on a flat surface. It also indicates that if you tilt the sensor forward between the range of 14 - 21.3 degrees the resistance should go from the 550 - 670 ohms to more than 100 kohms.

Also, did the ABS ever work on the car since you bought it?
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
1997 Impreza OBS

If you need to get a hold of me please email me rather then pm

chrisshara
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Re: ABS Fault Code 16

Post by chrisshara » Mon Jan 07, 2013 3:40 pm

Josh, you are correct. I did not mention that I performed basic continuity checks for shorts to power and shorts to ground. I think the most streamlined process for me to resolve this issue would be if I had the flow chart for this particular fault code. It seems like you have the flow chart for this fault code, as you have the service manual. If you could help me out by scanning the flow chart for fault code 16 to my email, I'd be happy to let everyone know what I've found.
94 Legacy GT
95 BMW (E36) 325ic
81 BMW (E12) 528i
04 Outback
02 Acura TL Type S

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Re: ABS Fault Code 16

Post by Legacy777 » Mon Jan 07, 2013 6:31 pm

I'll try and scan you something this evening.
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
1997 Impreza OBS

If you need to get a hold of me please email me rather then pm

chrisshara
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Re: ABS Fault Code 16

Post by chrisshara » Mon Jan 07, 2013 7:31 pm

Here is my email, if this helps. chrisshara@gmail.com. Thank you. No rush at all.
94 Legacy GT
95 BMW (E36) 325ic
81 BMW (E12) 528i
04 Outback
02 Acura TL Type S

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Re: ABS Fault Code 16

Post by Legacy777 » Tue Jan 08, 2013 3:27 am

Here's the flow chart for anyone that may be searching in the future.

http://www.main.experiencetherave.com/s ... ode_16.pdf
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
1997 Impreza OBS

If you need to get a hold of me please email me rather then pm

chrisshara
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Re: ABS Fault Code 16

Post by chrisshara » Wed Jan 09, 2013 2:48 am

Thanks ! I will keep everyone informed !
94 Legacy GT
95 BMW (E36) 325ic
81 BMW (E12) 528i
04 Outback
02 Acura TL Type S

chrisshara
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Re: ABS Fault Code 16

Post by chrisshara » Mon Jan 28, 2013 5:36 am

Ok, I finally had a free moment to troubleshoot this fault code with the flow chart provided by Josh. (Thank you very much Josh).

So, I ohmed the original G-sensor that I removed from my vehicle. It measured 565 ohms at the sensor terminal pins. I then measured the resistance of the replacement sensor that is now fitted into my vehicle. It measures 563 ohms. So they are both good G-sensors and relatively close in resistance value. I then removed my passenger seat and passenger door sill plate to lift up the carpet to gain access to the ABS control module. Once I had access to the ABS control module I verified that I had 12 volts going into the ABS control module (at pin #1 of connector P12). I then verified that I had (3) good grounds at the ABS control module (at pins #10, #20 and #34, connector P12). Knowing that my ABS control module has all the power and ground supplies needed to function, I can now look to other areas. I check to see if I had 12 volts at pin #2, connector B23. I verified that I have power going into my G-sensor. Per Subaru instruction, they don't recommend performing any voltage drop testing on the G-sensor. So I'm not going to interrogate how the G-sensor consumes the 12 volts that feed into it. It's the job of the ABS control module to manage that information and as long as my (3) grounds are good, then I'm at the point where I now need a know good ABS control module to plug-n-play for test purposes. And if Subaru's flow chart is on the money, I should be in good shape with a known good ABS computer.
94 Legacy GT
95 BMW (E36) 325ic
81 BMW (E12) 528i
04 Outback
02 Acura TL Type S

chrisshara
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Re: ABS Fault Code 16

Post by chrisshara » Tue Feb 11, 2014 4:29 am

UPDATE: After installing a "known good" ABS computer, my ABS continues to malfunction and store fault code #16.

I have been working with another gentleman who read this thread, has the same issues I'm experiencing and PM'ed me. Well, long story short, Jim has nipped his problem in the bud. And I'm fairly confident that I'm having the same issues as Jim.

Here is Jim's story:

Hi Chris,

Wow thanks for all your info. Well, where do i start ? Last Sunday, a part time rally driver/electrical engineer local to me, as a friend, called me up and said he had a spare hour to try and help me out. So, as i was at my wits end, I popped round. First, he got a resistor, approx 570 ohms, and soldered ends on it and spliced it into the yaw sensor harness. He told me to drive it, in an attempt to 'fool' the ABS control unit. Yep, the light didn't come on; but the pedal still pulsed when it shouldn't be pulsating. Since i had made a new harness between the sensor and the ABS control module and swapped an ABS control module from a friends Legacy who was in town from local Newcatle. upon tyne he said he didn't believe it was (sensor,harness,or ABS control module to trigger the fault code #16). So, we then started checking the resistance of each ABS wheel speed sensor, (((thinking outside the normal box; if you know what i mean.))) Well, back seat out, speed sensors read very close ohms which matched the osf but the nsf started at 1000 ohms then went tits up. So, I got a brand new ABS wheel speed sensor from a local subaru dealer of which he had it on the shelf since 1995. Freak, I know, but for £50 it was a bargain. Installed the wheel speed sensor on Saturday and the problem has been sorted FINALLY ! ! ! What I can not understand is how or why the ABS control module didn't store a wheel speed sensor code ??? Because after a year of troubleshooting, I was blinded by only thinking of the (3) instances where fault code #16 were stored and steering me toward G-sensor, wiring issues, or control module issues. Just goes to show check other items swell and never forget to think outside the box when things are not making sense within the box.

Chris, thanks for your time and help.

~Jim McDougall

****Just a heads up****

If you are getting fault code #16 and the flow chart for fault code #16 is leading you down a path to nowhere. Please run resistance checks on your wheel speed sensors. The rear wheel speed sensors on our cars have these lengthy metal brackets that secure the wire harnesses for the rear wheel speed sensors. And I have a bad feeling that when these brackets become really rusty and hold water, that these brackets and the moisture and rust help deteriorate the insulation on the rear wheel speed sensor harnesses and expose the wiring of the rear wheel speed sensors to the elements.

Jim, thank you so much for the great information. And thank your friend as well for me.
94 Legacy GT
95 BMW (E36) 325ic
81 BMW (E12) 528i
04 Outback
02 Acura TL Type S

Legacy777
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Re: ABS Fault Code 16

Post by Legacy777 » Sun Feb 16, 2014 1:01 am

Chris,

Awesome information!! Have you tested the resistance of your wheel speed sensors to confirm your issue is the same?
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
1997 Impreza OBS

If you need to get a hold of me please email me rather then pm

chrisshara
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Re: ABS Fault Code 16

Post by chrisshara » Sun Feb 16, 2014 7:38 pm

I have not gotten a chance. I just received this information the same day that I updated the thread. The temp here in Connecticut has not been over 32 degrees in over three weeks (translation: what seems like forever). My shop is not heated and I'm becoming extremely backed up with other projects because of the freezing cold temps. If I get some downtime Monday through Friday, I might have a moment to pull my car into the shop at work (where the shop is heated) to ohm out my wheel speed sensors. My shop is where I moonlight and weekend warrior.

Jim was able to confirm that his issue stemmed from his right front wheel speed sensor. So, I'd suggest that people who have this mysterious fault code #16 to first troubleshoot by the book and if everything checks out, then begin by ohming out the front wheel speed sensors.

If you think about it, the right front wheel speed sensor is right by the G-sensor. Maybe, somehow, the G-sensor and right front wheel speed sensor share something or have something in common that Subaru failed to figure into the flowchart for fault code #16 ??
94 Legacy GT
95 BMW (E36) 325ic
81 BMW (E12) 528i
04 Outback
02 Acura TL Type S

Legacy777
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Re: ABS Fault Code 16

Post by Legacy777 » Mon Feb 17, 2014 12:29 am

chrisshara wrote:If you think about it, the right front wheel speed sensor is right by the G-sensor. Maybe, somehow, the G-sensor and right front wheel speed sensor share something or have something in common that Subaru failed to figure into the flowchart for fault code #16 ??
Yeah I don't know....it may just be one of those weird and unintentional effects with the ABS computer. Subaru may have tested things as best as they could, but may not of been able to test every real-world scenario.
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
1997 Impreza OBS

If you need to get a hold of me please email me rather then pm

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