The dreaded Trans Failsafe Mode (again)

[upallnight]

Originally Posted by Siggy

My scanner came today. Bought the 520 off eBay on Friday, came today, Monday, from the other coast. I don’t buy much off eBay, but $159, free shipping. The guy has sold many, so I took a chance and it looks like it worked out.

Plugged it in, ran the auto scan, saved that, then reset everything. Transmission failsafe error is gone, transmission working perfectly again. After a few miles, the check engine light returned with the same error it’s had for months, P1093. I’ll chance that down now.

I’ll also work on a graph of the alternator. If anyone can kindly direct me to the right path to get there, I would appreciate it. Looks like learning the diagnostic tree structure is going to take me some time. Not knowing what’s available or what many of the acronyms stand for, it’s a little slow navigating.

But super happy so far. Money well spent.

When I had the P1093 (error code with the gear display light on the dash) I traced it to a bad MAF. Check the MAF and see if the PO replaced it. If it is not a Siemens MAF there's your problem. Spend the money and buy a real Siemens MAF or if you can't afford a new one, go to a pick N pull and find a real Siemens MAF. You can also look at data from the MAF with your new toy. What rate of air flow is the scanner reporting (g/s)?

[andrewwynn]

There is no doubt some learning curve.

There will be a lot of duplicates of DME and transmission modules etc so you need to learn which apply to you and remember.

For the voltage and rpm graph I picked BMW from first menu then auto sel Vin then control module then top engine module. In the engine module pic engine operating Values then live data.

From live data scroll through the long list and find rpm and battery voltage and check both and view.

It will start in text then hit the middle button will say something like 1 graph then again 2 graph.

That's all from memory so I could have missed something.

Don't get too adventurous in the section where you can reset things like the transmission until you need to. Eg set the air suspension to deliver mode etc. Some reset procedures have no cancel option when past a point of no return

[EODguy]

+1
What Andrew said earlier I screwed up an had an X5 "Zambonni" until Andrew helped me unscrew that issue...

Sent from my SM-A730F using Tapatalk

[andrewwynn]

I was actually thinking of that exact example. In my case I wanted to calibrate my air suspension but didn't know until after I started the car had to be on level ground BEFORE you start and there is no cancel/exit option!

Fortunately there is a "pull the plug" option (hold the reset button) but I wouldn't plan on that saving your bacon so only dive into the reset type options when they actually apply not just experimenting eg. transmission adaptations; meant for after an actual hardware change not because it's acting funny.

[Siggy]

Oh, it frightens me a great deal in the little I have looked around. I wish there was a printed tree of what's where. Especially on the testing front.

[andrewwynn]

Everything in the main sections is either read only or low risk tests like engage AC compressor. It will warn you if there are limits like "don't use more than once in 2 minute" etc.

[jsoto]

Brump. How long in minutes or is it just data points does the Foxwell graph ?

I've used my Fluke Connect series modules (DC volt and clamp) when looking at charging systems. My biggest gripe is the logging only does 10 minutes - whether it be a smartphone or computer. I can see the 10 minute cap on smartphone even though memory on smartphones are like 256GB+ and it's not the 1980's. But a 10 minute cap on a computer...

[Siggy]

Drove it with the scanner recording the voltage. It was reading 13.7 volts pretty steady, whether sitting at a stop light or driving along. Then I was sitting at a stop light, and I felt the compressor come on, looking at the scanner and saw 12.6, 12.8. The light changed, I started moving and it stayed at 12.8 for a few seconds and then it went back to 13.7.

I thought "Ah HA! That's it" and I've captured it in recording mode. I came back and went to the recording only to realize that when it's recording, it's taking snapshots. When I paged through all of them (517 data points), I could not find a single measurement in the 12's. That makes me wonder if I really saw what I thought I saw or if this happened and it wasn't long enough for the snapshot to capture it.

I have to assume that I did see what I thought I saw. If it did drop into the 12.6-12.8 range when the compressor came on, would that suggest that it is the alternator?

[andrewwynn]

I recorded a dip down to about 13 v when coming to a stop.

Can you graph like this with your scanner. It's probably normal to get a half volt drop but not a 1v drop. I got drops to about 12v when my alternator slip rings while being worn out also got coated in oil. I replaced the rings and brushes and no problems since.

[Siggy]

Originally Posted by andrewwynn

I recorded a dip down to about 13 v when coming to a stop.

Can you graph like this with your scanner. It's probably normal to get a half volt drop but not a 1v drop. I got drops to about 12v when my alternator slip rings while being worn out also got coated in oil. I replaced the rings and brushes and no problems since.

Yes, that's the graph I was recording when I saw the dip in voltage. However, when I go into the scanner and pull up saved data, it won't show the graph, it just shows data points and you page forward and backward to go through the timeline.

I'm sure there's no harm in putting a new MAF on. I think I'll try that. It's 144,000 miles now so I'm sure it's something that will need replacing sooner or later anyway.