jtbinvalrico

I recently read about the Autel AL619 scanner and thought I'd give it a try. I maintain a Nissan, a Mazda, and a Ford, and needed something that would work on all of them. This unit seems to be one of their new ones. A selling point is that it is supposed to do SRS and ABS on many domestics and imports.....including Nissan.

Like many, I'm dealing with the finnicky Nissan SRS system, which has seen me try all the tricks: checked every connector under and behind everything, did resistance checks on both airbags and both seatbelt tensioners, did a continuity check on the clockspring, etc. I don't want to deal with Nissan because from what I've read here and elsewhere, you take your car in, they read the code, and then begin replacing expensive parts, ie. clockspring, then the driver side module, etc. Reading those accounts, and even looking at the FSM rundown of how to address the problem, leads me to believe that Nissan has an approach to this that sorta looks like blindfolded dart throwing.

So, when I read about this scanner that can read and clear SRS, ABS, and a bunch of other OBDII stuff on my three cars, I bought one. It was about $143.00 shipped, from Amazon.

My SRS problem manifests itself in this way: I can get the light to go off, then it comes back on after a few minutes of driving. To see if it would work, I induced a fault by simply disconnecting my driver side airbag, then ran the scanner. With the airbag disconnected, it showed codes B1049 and B1054, which indicate an "open" driver airbag module. I then reconnected the airbag, cleared codes then re-scanned, and it showed all clear. Then sure as hell, after about five minutes of driving, the light came back on blinking steady on and off.

What have I learned? I believe I can rule out a lot of possible causes, including the modules, the connections, the clockspring, and the tensioners. I believe the steady flash indicates an "overall" fault or problem. The thing is, the new scanner indicates that it is communicating with the computer, and then clearing any codes. Furthermore, after clearing codes with the scanner, I get a steady flashing light again.....with no faults detected on the scanner. Remember, I confirmed that the scanner works and interacts with the system by inducing a fault and checking it.

Interestingly, I ran some other checks on the car. When I checked the ABS system, it showed that a "low voltage" code had been recorded at some point. I'm beginning to wonder if all this may point to something as simple as a battery that needs replacing.....it starts the car just fine, but not necessarily with what we might agree is that "new battery kick."

My current theory is, given that the SRS connections and components all check out, and given that the light will go off for a while and then come back on, the SRS system is seeing a fault or deviation in the electrical system which is making the main computer unhappy. The airbag modules and tensioners are monitored by the computer based on a reading of resistance, which I learned from the good folks at AirbagSystems is supposed to be around 2.5 - 3.0 ohms. Could a voltage variation associated with a battery issue cause this? I'll be replacing the battery (unknown how old it is anyway) in my continued pursuit of SRS zen.

Outside of all that, the Autel seems like a nice unit.......at least to this novice user. It interacted with and read all my vehicles nicely. Diving further into it, it also reads and does real-time graphs of quite a few engine parameters that might be of interest to the more performance-minded folks here. I'll gladly answer any questions I can about it as it relates to our 350Z platform.

jtbinvalrico

Here's some pix and screen shots of the Autel AL619 hooked up to my 350Z:



























Frankly, I do what most here would consider "basic" maintenance, so a lot of what it will do is beyond the scope of my skillset. It also does recording and playback, prints, and has a removable data card on its right side.

SRS update: My battery was five years old and needed replacing anyway, but that didn't totally eliminate the problem.

I'm getting and repeatedly clearing a B1049 code. The B1054 is gone. I wish I knew the difference between a B1049 and B1054, since it was setting both when I unhooked the airbag for a test. Unfortunately, it seems that Nissan will do little more than tell you, "it's setting a B1049 and B1054, so let's start replacing stuff."

Perhaps B1049 is for one of the leads to the airbag, and B1054 is for the other, which suggests an intermittent wiring issue, which points to the clockspring. So......I ordered a new clockspring today at $130. Updates to follow.

jtbinvalrico

The new clockspring fixed it.

Looking back at it, all signs pointed to an intermittent fault. If you are repeatedly resetting the airbag light and getting a new fault down the road, the odds are that the fault is indeed fixed as you sit on the driveway, but as you drive the car and move the steering wheel one of the lines in the clockspring cable briefly breaks its connection and sets the fault. Then begins the frustrating cycle of resetting it and going through this all over again.

This seems simple enough. But when you or Nissan put the scanner on it, it may or may not show the code, depending on whether or not the "intermittent" fault is occurring right then and there. So the code is cleared, but the airbag light keeps flashing.......and if you read it at just the right time, you'll get a B1049 or B1054. Read it at the wrong time and you won't. In short, a flashing airbag light does not necessarily equal a code on the scanner, but a code on the scanner always equals a flashing airbag light.

When Nissan sees this, they start replacing parts on your dime. If they start with the clockspring and remedy it, you are only out the diagnostic fees and parts and labor.......you can replace the part and get yourself a new scanner for less.

The airbag itself is easy enough to bench-test for resistance across the terminals. I read about bench-testing the clockspring. I did it and know believe it's pointless. I tested for continuity on each wire run in the clockspring and it passed on my bench. The reason this test is pointless is that a bench test does not account for the wide degree of movement the cable makes as it is moved to and fro in the wheel. You'd have to make up a jig to monitor each lead and then attempt to detect what may be a very brief interruption in the signal on your meter......or buy the new clockspring for $130.00.

In my case, my reliance on a flawed method of bench-testing the clockspring misdirected my efforts; being able to read and clear my own codes got me back on track.