Battery??
 

My son came home and said."dad...lights are on again". We just had the steering angle sensor and yaw sensor done. This time the 4x4 light and the brake light came on along with a message "engine failsafe mode". I ran a scan and it said engine idle control valve stuck open. Cleared codes and all lights went out. Seeming that none of these seem to have anything to do with the other and the car was running fine...could it simply by a battery that's going low?

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I would say not likely....When battery dies you will get funny symptoms, but not typically the ones you describe. You should check battery voltage (parked and running), which you can do with cluster sub-menu (look it up)

Who did the steering angle and yaw sensor? I think one and possibly both have to be reset with INPA or some other computer tool after replacement.

was the idle speed error the only error code you got (other than the lights and failsafe mode message)? I guess I would drive it and see which codes come next.

Yaw sensor was done a bit ago. Angle sensor about a week ago. Yes , that was the only code. May be some random old BMW thing. Odd the brake light came on as well...that never happened. I'll have my indy who did the work look at it and dona scan. Pretty much every sensor was done on this car in the past 2 years as well as a new engine. Weird thing is, it always runs fine, regardless of the warning light.

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if you don't know the age of your battery, you might also dig into to see a date code. It's good info to have. On an X5 I bought a year ago, I just had an AGM battery dated 12/2016 fail on me. I replaced with w/a non-AGM H8 from Wal-Mart for $129.

I have been getting 6-8 yrs out of my batteries in my E39. I live in New England with annual temp ranges from zero to 100F.

Did the ABS light also come on with the 4x4 and Brake light?

test don't guess as you only need a volt meter and access to the battery itself to get good actual not processed numbers.

Starting & charging systems testing techniques
Without spending too much time on starting & charging systems testing techniques, here are a few quick tests to determine a battery issue, a charging system issue, or a primary wiring issue.

Tools required: Digital Volt Meter (DVM), battery terminal cleaning tool, and 8mm, 10 mm sockets and ratchet with extensions.

You need to read battery voltage before starting any test on an electrical system as it will influence the results of Starting, Charging, and electrical tests of any kind. (Note: battery must be fully charged, see chart)

Step one: Get out a digital volt meter, Read battery voltage (Key off). Read voltage (Key on) at the following points Battery, under hood jump point, and at the alternator. You only need to determine if you have 12 volts at the alternator with the key on (BIG FAT WIRE). A simple handheld digital wave form tester will get you in the ball park when it comes to batteries. (Further discussion on these testers is for another engineering forum). I have a handheld Chrysler tester that was put out in 1980 to help low skilled techs determine charging system functionality. It has three lights: Battery voltage good (12.6v), Alternator good (13.5v), Fault (anything else). That’s it. I had this in my bag of tricks when I sold auto testing equipment.
Step Two: You need to read the voltage at the BATTERY at idle, 1500, and 2500 RPM to determine voltage regulator function. Better still would be a Volt Amp tester (VAT-40 Image below) to induce a correct AMP load to read actual AMP/Volt output from the alternator and battery, as that is the only true testing method. Having a DVM that has min/max capability will make your testing easy.
Step Three: Remove and clean each and every ground in the trunk, jump point, and at the frame rail for the block (bad grounds = lots of electrical issues). Clean the starter/alternator cable connection under the car, just under the dead pedal.
Step Four: Failure to get correct output on running test means DEAD alternator (volt regulator, brushes, windings, etc.) Remove and bench test the unit or drag it to your local auto parts store for a second opinion (which will be worth exactly what you pay for it....)

Base line numbers
Battery Voltage should be 12.6+V (Key off) See chart below.
Battery voltage should be 13.5v - 14.5v on running tests (note large fluctuations at running RPMs is a SURE sign that the Volt Regulator is not doing its job. Smack with rubber hammer and retest. Rebuilt units have large variance of quality control from good 85% of the time to approx 50/50%.

NOTE: The exact charging voltage will vary according to the battery's state of charge, the load on the vehicle's electrical system, and temperature. The lower the temperature the higher the charging voltage, and the higher the temperature the lower the charging voltage. The "normal" charging voltage on a typical application might be 13.8 to 14.3 volts at 77 degrees F. But at 20 degrees F. below zero, the charging voltage might be 14.9 to 15.3 volts. On a hot engine on a hot day, the normal charging voltage might drop to 13.5 to 14.3 volts.

Note 2: TIS specifies alternator voltage as 14.3 +/-0.1 V. But that is measured at the alternator output post. The values seen using the cluster will be 0.5 V or more below the alternator voltage output.

Batteries surface charge.

What the heck is a surface charge?
When testing wet cell auto batteries, some will show a 12.xx Volt result, but as soon as a 100-150 amp load is applied, they drop straight down to 9.8V or lower. Classic example of a collapsed cell wall (internal short). This is why too many DIY and techs get stumped when they pull out a meter and say "It shows 12.xxV so it must be good”. NOPE, batteries are tested for voltage holds and AMP draw capacity as well as the ability to recover and recharge over and over again. Batteries are nothing more than an energy storage device. Their usage back in the 1920's allowed for a "self-starter" option, Now days we take it for granted. In the future we will use the engine ignition system to fire off a cyl while disabling all other cyls (opening the exhaust valves) allowing for a start that requires no electrical/mechanical starter. A topic for a SAE publication but an interesting future none the less. The challenge is for the average DIY to approx the load test with KEY OFF.

Solution: Set a volt meter to DC volts 0-25 scale or auto ranging if so equipped. Read and record voltage
Turn on everything in the car for 15 seconds:
Headlamps to high beam
Heater blower motor to high w/ A/C on
Seat Heaters
Rear Defroster (and rear seat blower if so equipped)
Interior lights
Radio
Fog lamps
Cigar lighter
etc, etc, etc

Read voltage after testing. You should see a drop off of .5-1.5Volts during the test and a slow rise back to 12.5V+ on a completely healthy and fully charged battery in 30sec to 1 min.
A battery that is DEAD, will show 9.8V or less and never recover until charged.

Battery Registration: There is NO battery registration required for proper operations in a E39 or E53 application.

Alternator testing tips
To quote another poster...

How to load the alternator at engine idle for alternator output tests:

Note: Alternator output should be tested with the engine idling under the following four loads after at least 15 seconds of idling (for the alternator to ramp up):
Turn the high beams on
And, turn the rear defroster on
And, turn the fan on (full force, I guess)
And, turn the wipers on (to the regular setting, I guess)

These loads should be left on while the alternator output tests are being performed.

Once access to the alternator is gained (access for the I6 is vastly easier than the V8):

• Check the voltage from the alternator #30 post and ground
o It should be the same as the battery voltage
• Now disconnect the harness connector to the alternator:
• Check voltage from terminal 15 and ground (field voltage)
o It should be the same as the battery voltage

More info: Another way to check alternator output is with an oscilloscope. Observing the "ripple voltage" pattern will tell you at a glance whether or not all the alternator windings are functioning. A "good" pattern should look like the top of a picket fence. If any of the humps are missing, it means one or more of the windings is grounded or open, or there's a bad diode. Most battery/charging system testers also have a test function that can detect bad diodes.
Ripple testing with a DVM:

ANOTHER QUICK CHECK FOR BOSCH ALTERNATORS

One way to check the integrity of the alternator and diodes on Bosch alternators is to check the voltage readings at the D+ (blue wire) terminal and B+ terminal. The voltage reading should be the same at both terminals. A difference of more than one volt would indicate faulty diodes and the need to replace the alternator.
Tips link: https://www.diyauto.com/manufacturer...ion-by-bluebee

Volt Drop Testing (Image below) will show you issues with grounds and wiring problems. Read the text and test a few spots to determine if your car has clean connections.
https://www.engine-light-help.com/voltage-drop.html

Are you having other electrical issues? Alternative issues: Ign Key switch failure, wiring junction box rusted (see water leaks under passenger seat(E39), Water standing in trunk under the battery (E53) and the normal wiring broken connectors, grounds), etc....

Tip Sites for more info:
https://www.aa1car.com/library/2002/cm10220.htm
https://www.bimmerfest.com/forums/sh...d.php?t=510579 (Everything you wanted to know about BMW starting and charging systems for DIY)

Helpful?
Attached Thumbnails

Low voltage for 1/2 a second will trip and/r4x4 but also brake light should have come on. If alternator is weak long enough you will also get engine failsafe and transmission failsafe.

Clear all the codes and bring up real time voltage on the hidden OBC menu (test 7 or 9 I think), if the voltage drops more than 1/2v when you release the gas pedal e.g. coasting before a stop the alternator needs work.

On both of my X5 that just meant replacing the brushes (at about 130,000mi for me and 180,000 for wife's) was all that was needed. My repair stopped working after about 40,000 miles but it turned out to just be carbon dust buildup so I kept my old alternator as a spare I can bring with on long trips.

Look for my alternator repair threads. I describe how to reverse the polarity on the armature winding and nearly double the lifespan of the slip rings (one gets 80% of the wear). New brushes and flip the polarity should get you 80-100,000 more miles.

My engine bay is suffering from an oil leak right now that apparently made the carbon dust from normal wear clump up and made the alternator malfunction, so I replaced it only to discover a shot of brake cleaner in the brushes would have brought it right back to life.

@StevenVA:

Great info, I sure hope you had that saved in a file to copy and paste!

I have posted this approx 20x times
It all sits in a folder called Starting/Charging System testing. Blows my mind that every newbie asks the same 5-8 questions without any searching or even looking at the DIYs.
Most start with I just purchased a X5 that has been sitting for xx months (ever wonder why?) with a dying battery and now XX is going on. Gee, how could that be?

You have been very tolerant and helpful as always which is always a good thing.
Knowledge is always transferable if the receiver is turned on.....

That's a great line. I'll remember that. The problem with search is that more often than not it's very difficult to find the right search phrase, and a newbie is always a newbie doesn't matter if they bought x5 2020 or 2010. Many many people really did zero maintenance on their own car because they had a virtually zero maintenance car or one that was not cost prohibitive to bring to a shop so buying used X5 they are quickly getting up to speed on the necessity of DIY.

Since the day I bought mine, I tell oeoe that I budget $100/mo for upkeep and do all the maintenance myself to keep under budget. It's not a car for somebody that can't DIY.

Example: $300+ repair for door actuator that needs $12 of parts and 90 minutes of my time.

DISA valve: $350-400 at dealer, 12¢ of screw and nuts to DIY repair myself. (that's probably the biggest one percent wise).

I agree, we need more of a insert/check off problems = here are your posting related to your issue(s). Solution in a box type of format. But unfortunately, the lack of postings and readers leave us with a few die hards and newbies as the content makers.

That's a great idea a sticky thread with a list for newbies and links to the corresponding thread with the topic covered

I looked around a few forums before I settled here because it seems to be the most active by far.

On a regular day I notice there is well over a 100 people browsing the e53 forum. Usually closer to 200.

Seems like there's a lot of more interest here than the newer Xs

I agree with the stickies

On many of the forums that I frequent they'll have several stickies starting with an FAQ.

I don't know why there isn't any of that here, seems like there's been plenty of time.

Maybe if someone is friendly with the moderators we can spruce the place up a bit?

Look up top on the forum and see and clink on ARTICLES. They have never been updated to my knowledge in the past years so there are more hidden away in postings all over the board. It would however make for a good Data content deep dive for the admins.

Man that reminds me of the Friendly Giant

look up waaaaaaaaaaaaaaaaaaay up!

In all my years of lurking in forums I have never seen anything placed there.

Maybe it's just me but that's definitely not where I would even consider looking. I would expect it to be at the top of the subforum I'm currently in like...


https://i.imgur.com/e1uk6Pp.jpg

The great news is that the X5 E53 shares the same engine, engine management, body part complexity as the E39 so what works on one works on all. So hit up the other forums for testing, repair solutions etc.

Sure you could go somewhere else...but I'm at Xoutpost with an X. They should have me covered :D

/thread back on topic

This is Truth. I have 3 years of receipts from the PO totaling $30k to the dealer for maintenance. Who can afford $10k per year in maintenance? And why would you, even if you could?

I learned from my dad eons ago better to buy the specially tool than hire the guy who has one, in most cases you break even on the first job. It was far far more difficult to repair a car before the internet

I bought a 2002 330ci convertible last year. The previous owner had all the records for the 10 years he had it. 14k worth service in that time and nothing major was replaced. The mechanic was an independent shop that specialized in European vehicles and they upsold and charged this guy every single thing you can imagine.

He goes in for a complete brake job, drops and grand in parts and labor and they charged him to top up his fluids :rolleyes:

There's quite a few things they charged for that I think is sort of hitting below the belt. Along the lines of going in for a bad bearing and the mechanic charging $75 for a diagnostic fee which I'm pretty sure would consist of wiggling the tire.

I bet that mechanic will be sorry buddy sold the car.

:iagree:

over the years I've learned that even if I do all the work myself I'm still way ahead in cost (At least for my pay grade anyway) AND I get to keep the tool.

Many of the high ticket jobs I've done myself were high ticket because it was mostly grunt work that takes time, specially here with the winter and salty roads. Ball joints can take an hour or days depending on what I'm dealing with and where I'm working, like a driveway...in the winter...while it's snowing.

The internet makes it almost too easy. I watched a guy on youtube tear apart a transmission literally in 40 minutes. He did it all pretty much in real time and presented everything in a way that made it look fairly straightforward. Depending on the cost of a rebuild kit I might want to give it a whirl once the transmission on the convertible goes (please don't jinx me, please don't jinx me)

There are some fantastic resources out there for us car guys and I've been on forums where there were literally guys who built or designed the cars we're talking about pop in and give advice.

Before I bought my first x5 I searched for both a complete motor and a complete transmission. I found both at reasonable price so I jumped in head first.

I have a customer has a 328xi it's more like e70 than e53 but I've done some major repairs including the electric water pump and the biggie! Transfer case! Found a decent used one for $500 including shipping.

Funny oversight in my pre purchase research I missed that it took premium gas. Oops.

You’ve got the right attitude, but don’t do a transmission yourself. That’s the one thing that’s almost impossible to do correctly. You need very specific manuals and tools and testing.

You can swap a transmission mostly DIY might need help to wrangle the thing around, but I don't think any fancy tools are needed, I even saw a trick where a guy put a dolly under the xm, blocked it tight with wood blocks and then lifted the from of the car up to pull the xm out the front of thre car. Clever no lift solution. I would probably use a floor jack and some wood like I did with the transfer case.

Especially on a vehicle that isn't worth that amount. Not even close. Money to burn I guess. :dunno:

I tell people all the time as long as you do all the work not too expensive to maintain but clearly once maintenance is more than a lease payment no point

Watch the videos on youtube with Gary Ferraro tearing apart the ZF5HP19 and maybe you'll feel the same way as I did.

The teardown doesn't involve any special tools and I can't imagine putting it back together is any different.

50s kid also rebuilt his own transmission in his garage and he's a software programmer :dunno:

I'm sure it's not easy per say, but I think transmission work is something that most people (myself included) think of as sorcery but it's obvious from the shops I visited not everyone is a necessarily a wizard :D