[AndyDaBoss]

Water pump finally failed at 56k miles on my 335i '08 and need help concerning the reason of failure and horrible experience with dealership and 3rd party extended warranty.

Warning!! Long story please take time to read.

So 2 nights ago while headed back to houston from San Antonio my car suddenly overheated . A yellow thermostat symbol came up followed by a red one . Unlucky for me I was in the middle of nowhere and at the worst spot possible . There was no shoulder for me to get on since I was on a BRIDGE. Waited for local police to escort me to safety meaning driving 5-10 mph to the nearest gas station 2 miles away ... After that I waited around 4 hours for a flat bed tow truck to tow the car BACK to the San Antonio bmw dealership, now keep in mind this is already around 3 in the morning so I would have to wait the next morning for the dealership to open, so okay i think everything will be fine im off work anyways. so i spend the night at my sisters dorm on campus thinking ill be on my way home after they fix it. Dealership calls me 8 in the morning saying they are going to replace the water pump but not the thermostat... So I agreed and had them go ahead and fix the car up. So they call me late afternoon saying my car is finally done so I come and pick it up . Now when I drove the car off the dealership, it didn't feel as if the car was driving correctly but I just ignored it thinking it was just getting use to the new pump. Well 30 minutes into the drive back to houston my car suddenly went into limp again and the same symptoms happened, yellow followed by red sign, at this point I was furious because I was once again stuck on a unsafe location and had to wait another hour to tow the car back to the dealership . Here's the catch , the dealership closes at 6pm and its already 5:58 by the time we got back. All the service advisers were getting ready to leave and non of them wanted to stay late to help me so I'm pretty much screwed because now I have to wait the next friggin day for them to check what the problem was . So I pretty much went through the same damn process twice. now i would have to miss a day of work to stay in San Antonio to wait the following day so I decided to go to the river walk with my sister since I'm going to be here another day . Ok so earlier this morning dealership called me and told me that it's the intelligent battery sensor thats faulty which is causing the water pump to fail . FYI I'm out of manufactures warranty and I'm using NAC extended warranty to cover all this .

My question is
1) can the ibs sensor really cause the water pump to fail

2) can driving 5-10 mph while car is overheating damage the engine

3) what other components can cause the water pump to fail and would a faulty thermostat throw any codes

Thank you for taking your time to read my horror story I'm still in the process of waiting to get my car back hopefully later today

I will edit the experience with extended warranty company later today since I'm writing this early in the morning

Update: Ok so SA told me the ibs was faulty, causing the water pump to fail but now they're saying that my alternator has gone bad which is hard to believe but now they are waiting for the 3rd party warranty inspector to come to inspect my car since repairs cost over a dollar amount. but now I'm worried because I'm modded and they already paid $1500 so far in repairs without having someone come check out my car . Everything seems like its going down hill . 3rd party warranty didn't want to cover the ibs because they said its not covered under the agreement plan so I told them to tell me where in the agreement plan it says that. long story short they couldnt find it and ended up paying for it . NAC is a very shady company guys so beware!!

Do you guys think they will make me pay them back for the repairs since I'm modded (dci, cp/bov, jb4, muffler delete) I didn't get a chance to remove anything since this was unexpected but I did put jb4 to map 0

UPDATE: The dealership is now blaming my jb4 on all the component failures !!! are you kidding me ? they said they found a performance chip when trying to reprogram the dme. The tech said that after replacing alternator the car was still having problems and were then blaming the jb4 from letting their cable thing pass to the dme. how is that possible when i set the jb4 to map 0 ?! anyone care to explain what the dealership is saying?

[SharkBait]

Originally Posted by AndyDaBoss

2) can driving 5-10 mph while car is overheating damage the engine

Generally a bad idea. Heat kills engines. Stop. Open hood. Wait. Then drive 2 miles.

[Fun w/N54]

1. Not sure
2. Yes.
3. Yes but probably hidden BMW codes that can't be read with generic OBDII reader. I'm thinking t-Stat stuck closed. Normally this is replaced WITH the water pump.

Check your paperwork.
GL

[Meeni]

IBS that fries the pump ? Possible but protracted. Other electronic would fry as well. Pretty scary IMO, if that was the case, you don't know what else is going to die tomorrow.

Driving (even low speed) w/o a pump will damage the engine. Wait for temperature to get low again before resuming motion, if -really- needed.

Faulty thermostat throws shadow codes that can be read only by BMW diag tools. It fails open, so it should not cause overheat. The thermostat is usually replaced at the same time, because the work is shared (it is attached to the water pump).

[MountainStone]

Originally Posted by Meeni

...It fails open, so it should not cause overheat...

It fails open? What have the germans engineered now? With no water temp gauge, how would one ever know the thermostat had failed?

[GoRomeo]

Wow what a story. From what I have read, our thermostats were designed to fail open, not close. If our thermostat has failed open it our engines would take longer to reach normal tempetures but not overheat. Check your voltage on your battery and make sure is not high. If it is this is probably true the fact that IBS caused water pump to fail. Keep us posted and good luck!

[Meeni]

Originally Posted by MountainStone

It fails open? What have the germans engineered now? With no water temp gauge, how would one ever know the thermostat had failed?

The car has several temp sensors. They are not visible on dash, but they are in the engine and you can read them through the ODB plug.

[DC_Oldboy]

Sorry to hear bro that bro. Hope things work out for you!

[AndyDaBoss]

Originally Posted by GoRomeo

Wow what a story. From what I have read, our thermostats were designed to fail open, not close. If our thermostat has failed open it our engines would take longer to reach normal tempetures but not overheat. Check your voltage on your battery and make sure is not high. If it is this is probably true the fact that IBS caused water pump to fail. Keep us posted and good luck!

Update: Ok so SA told me the ibs was faulty, causing the water pump to fail but now they're saying that my alternator has gone bad which is hard to believe but now they are waiting for the 3rd party warranty inspector to come to inspect my car since repairs cost over a dollar amount. but now I'm worried because I'm modded and they already paid $1500 so far in repairs without having someone come check out my car . Everything seems like its going down hill . 3rd party warranty didn't want to cover the ibs because they said its not covered under the agreement plan so I told them to tell me where in the agreement plan it says that. long story short they couldnt find it and ended up paying for it . NAC is a very shady company guys so beware!!

[mike3000fl]

I have a stuck open thermostat and it throws a P code that can be read with any OBD-II scanner, like the free one they do at autozone.

Can't remember what the exact code is but if they scan it at a autoparts store, write it down and check it on google because they told me it meant bad cruise control and when I googled it, it was for the thermostat.

anyway, like mentioned, they fail open on our cars which means the car won't overheat, it will actually always run cooler than optimal temp and take longer to warmup.

[triger716]

Originally Posted by mike3000fl

I have a stuck open thermostat and it throws a P code that can be read with any OBD-II scanner, like the free one they do at autozone.

Can't remember what the exact code is but if they scan it at a autoparts store, write it down and check it on google because they told me it meant bad cruise control and when I googled it, it was for the thermostat.

anyway, like mentioned, they fail open on our cars which means the car won't overheat, it will actually always run cooler than optimal temp and take longer to warmup.

+1 They are designed to fail open and should throw a code. At least in my case the check engine light was also on because of the failed thermostat.

[GoRomeo]

Originally Posted by mike3000fl

I have a stuck open thermostat and it throws a P code that can be read with any OBD-II scanner, like the free one they do at autozone.

Can't remember what the exact code is but if they scan it at a autoparts store, write it down and check it on google because they told me it meant bad cruise control and when I googled it, it was for the thermostat.

anyway, like mentioned, they fail open on our cars which means the car won't overheat, it will actually always run cooler than optimal temp and take longer to warmup.

Yeap I had these codes too P0128 for stuck open thermostat and P0197 for bad cruise control. This p0197 dont know where it came from cuz my cruise control has always worked fine. Anyways, I was able to clear these codes with TORQUE app. No issues till today.

[Maestro]

Okay, I am trying to figure out how the intelligent battery sensor (IBS) could damage or fire a water pump. We are talking about a 12V system here and not sure how a sensor can cause an electric pump to be damaged, this makes no sense whatsoever. The Senor only reports the health of the battery and provides some feedback to the charging system to how much of a charge the battery needs.

[ken1137]

Do you guys think they will make me pay them back for the repairs since I'm modded (dci, cp/bov, jb4, muffler delete) I didn't get a chance to remove anything since this was unexpected but I did put jb4 to map 0

No...b/c your mods did not cause the failure. The dealer also has to prove it caused the failure versus just saying it. Sorry to hear about the problem and good luck.

[Meeni]

Originally Posted by Maestro

Okay, I am trying to figure out how the intelligent battery sensor (IBS) could damage or fire a water pump. We are talking about a 12V system here and not sure how a sensor can cause an electric pump to be damaged, this makes no sense whatsoever. The Senor only reports the health of the battery and provides some feedback to the charging system to how much of a charge the battery needs.

The IBS controls how much juice the alternator sends in the system. The alternator is quite a strong thing, it pumps out 12V, but with insane amps. So if the IBS tells the alternator to do something very stupid, it may result in electrical bbq.

That being said, most issues of the sort are related to a faulty alternator regulator.

Ask to have the DME codes they read.

[fun2drive]

Raise the BS flag. The IBS cannot cause any electrical system on the car to fail since it doesn't regulate voltage the voltage regulator (DME to rear power distribution box) does. The IBS collects information from the battery and other information but isn't a contoller.

Some background--------------------------------------------------------------------
E90 Voltage Supply & Bus Systems
Introduction
The voltage supply system on the E90 uses a Junction Box (JB) with a control module
as a primary power distribution point and bus system gateway. To ensure balanced
energy management in the vehicle an energy management function similar to that used
in the E60 is utilized and is incorporated into the operating software of the DME.

Now the IBS
Intelligent Battery Sensor (IBS)
The Intelligent Battery Sensor (IBS) as a mechanical/electronic device which is connected
directly to the negative battery terminal.
The IBS contains a micro processor that is used to monitor/measure various battery conditions
such as:
• Terminal voltage via measurement from B+ to Gnd
• Charge/discharge current via integrated shunt resistor
• Temperature of battery acid via integrated temp sensor

IBS Measuring /Evaluation Function
The measuring/evaluation function of the IBS electronics, continuously measures the following
values under all vehicle operating conditions:
When the vehicle is stationary, the IBS is programmed to wake up every 14 sec. and
makes the required measurements within approx. 50 ms in order to save power.
The measured values from the IBS are provided to the DME by way of the Binary Serial
Data Interface (BSD) to calculate the State of Charge and State of Health for the battery.
• State of Charge (SoC) is a calculated condition showing the current charge of the
battery. SoC is used during key “OFF” periods to insure the battery maintains a sufficient
charge to start the engine at least one more time.
• State of Health (SoH) tracks the history of the battery in the vehicle. Charge/discharge
cycles and times are monitored. SoH helps the DME determine the proper
charging rates and anticipated battery life. Internal resistance of the battery is calculated
by the IBS from the current and voltage dip during engine start. The values are
forwarded to the DME to calculate the SoH of the battery.
Software contained in the microprocessor of the IBS utilizes the measured values to calculate
the State of Charge (SoC) of the battery during vehicle sleep mode and compares
this information with that received from the DME/ECM pertaining to the battery SoC/SoH,
during the period of time between engine “OFF” and deactivation of the DME main relay.
The current SoC/battery data is stored in the IBS every 2 hours over a 6 hour time frame,
providing 3 - 2 hour snapshots of battery SoC information. The stored information/snapshot
data is overwritten every 6 hours. Whenever KL15 is activated the IBS updates the
DME with the current closed circuit histogram/battery status information, byway of the
BSD. Upon obtaining updated information the DME evaluates the new data and if a
closed-circuit current draw is identified a fault will be stored in the fault memory of the
DME.
• Voltage (6 V to 16.5 V) • Starting Current (0 A to 1000 A)
• Current (200 A to +200 A) • Temperature (-40°C to 105°C)
• Closed Circuit Current (0 A to 10 A)

This is right from the BMW training class minus some of the diagrams. It is the DME that steps voltage up not the IBS.
-------------------------------------------------------------------------------------
My opinion is that the IBS failed because either you had bad luck and it happens or the battery was changed incorrectly and shorted the IBS out which also happens.

There is no way in hell the IBS caused your water pump to fail. The failure was either short to ground or mechanical leakage of the housing or seal of the water pump (my guess here). If the IBS fails the DME speeds up the idle to provide sufficient power to the system until you repair the IBS. Also the pump has to be designed to run at higher voltages other than 12VDC since the alternator will provide up to 14.5VDC.

I think this dealer is giving you a bill of goods on some explanation. My guess is that the SA was told by the tech that IBS failed and he told you that caused the water pump to fail. This could just be ignorance about how the systems work and you can't expect a SA to know everything but I think these are two separate failures not related to each other...

I hope this helps some. I could not get the diagrams to post unfortunately which would have helped show the system layout...

[Sparkee]

I concur with all the comments about damage to the engine by driving with it overheated.

The IBS is actually a small microprocessor with sensors embedded in the negative battery terminal connector. It reports status directly to the DME over a serial data connection. I do not believe it directly controls the alternator in any way other than perhaps indirectly by confusing the DME. IMHO the DME would throw some kind of code (maybe not readable by a standard reader) if there was an issue, and I firmly believe the DME would not cause the alternator to over or under volt the car as a result of such an issue.

In summary, IMO there is almost no way a faulty IBS can cause a waterpump to fail. The E90 water pumps are known to do that well enough on their own.

Edit...
I see a much better answer than mine got posted while I was typing...

[GoRomeo]

cool stuff to learn... Keep it coming guys... LOL

[Fun w/N54]

That and the output of the regulator would tie to the input side of the fuse box where the water pump and ALL other circuits are feed off of. Soooo yes it's hard to believe that only the water pump would of fried under this 'suspect' condition or state.

Good Luck

[AndyDaBoss]

Originally Posted by fun2drive

Raise the BS flag. The IBS cannot cause any electrical system on the car to fail since it doesn't regulate voltage the voltage regulator (DME to rear power distribution box) does. The IBS collects information from the battery and other information but isn't a contoller.

Some background--------------------------------------------------------------------
E90 Voltage Supply & Bus Systems
Introduction
The voltage supply system on the E90 uses a Junction Box (JB) with a control module
as a primary power distribution point and bus system gateway. To ensure balanced
energy management in the vehicle an energy management function similar to that used
in the E60 is utilized and is incorporated into the operating software of the DME.

Now the IBS
Intelligent Battery Sensor (IBS)
The Intelligent Battery Sensor (IBS) as a mechanical/electronic device which is connected
directly to the negative battery terminal.
The IBS contains a micro processor that is used to monitor/measure various battery conditions
such as:
• Terminal voltage via measurement from B+ to Gnd
• Charge/discharge current via integrated shunt resistor
• Temperature of battery acid via integrated temp sensor

IBS Measuring /Evaluation Function
The measuring/evaluation function of the IBS electronics, continuously measures the following
values under all vehicle operating conditions:
When the vehicle is stationary, the IBS is programmed to wake up every 14 sec. and
makes the required measurements within approx. 50 ms in order to save power.
The measured values from the IBS are provided to the DME by way of the Binary Serial
Data Interface (BSD) to calculate the State of Charge and State of Health for the battery.
• State of Charge (SoC) is a calculated condition showing the current charge of the
battery. SoC is used during key “OFF” periods to insure the battery maintains a sufficient
charge to start the engine at least one more time.
• State of Health (SoH) tracks the history of the battery in the vehicle. Charge/discharge
cycles and times are monitored. SoH helps the DME determine the proper
charging rates and anticipated battery life. Internal resistance of the battery is calculated
by the IBS from the current and voltage dip during engine start. The values are
forwarded to the DME to calculate the SoH of the battery.
Software contained in the microprocessor of the IBS utilizes the measured values to calculate
the State of Charge (SoC) of the battery during vehicle sleep mode and compares
this information with that received from the DME/ECM pertaining to the battery SoC/SoH,
during the period of time between engine “OFF” and deactivation of the DME main relay.
The current SoC/battery data is stored in the IBS every 2 hours over a 6 hour time frame,
providing 3 - 2 hour snapshots of battery SoC information. The stored information/snapshot
data is overwritten every 6 hours. Whenever KL15 is activated the IBS updates the
DME with the current closed circuit histogram/battery status information, byway of the
BSD. Upon obtaining updated information the DME evaluates the new data and if a
closed-circuit current draw is identified a fault will be stored in the fault memory of the
DME.
• Voltage (6 V to 16.5 V) • Starting Current (0 A to 1000 A)
• Current (200 A to +200 A) • Temperature (-40°C to 105°C)
• Closed Circuit Current (0 A to 10 A)

This is right from the BMW training class minus some of the diagrams. It is the DME that steps voltage up not the IBS.
-------------------------------------------------------------------------------------
My opinion is that the IBS failed because either you had bad luck and it happens or the battery was changed incorrectly and shorted the IBS out which also happens.

There is no way in hell the IBS caused your water pump to fail. The failure was either short to ground or mechanical leakage of the housing or seal of the water pump (my guess here). If the IBS fails the DME speeds up the idle to provide sufficient power to the system until you repair the IBS. Also the pump has to be designed to run at higher voltages other than 12VDC since the alternator will provide up to 14.5VDC.

I think this dealer is giving you a bill of goods on some explanation. My guess is that the SA was told by the tech that IBS failed and he told you that caused the water pump to fail. This could just be ignorance about how the systems work and you can't expect a SA to know everything but I think these are two separate failures not related to each other...

I hope this helps some. I could not get the diagrams to post unfortunately which would have helped show the system layout...

Very interested write up ! I now believe that they can't connect the dots between what is going on with my car and guessing which components they need to replace will solve this problem . I told them to wait til the car is warmed up and test drive it for at least 10 miles . That way if it breaks down , I won't have to go through the whole process again , which it will be on them . They however did loan me a 2013 328i which I'm grateful for cause they probably knew I smell something fishy is going on . At first when i asked for one, they told me they had no loaner cars and that my warranty didn't cover loaners but after all this fuss they didn't hesitate to give me one.

[GoRomeo]

Originally Posted by AndyDaBoss

Very interested write up ! I now believe that they can't connect the dots between what is going on with my car and guessing which components they need to replace will solve this problem . I told them to wait til the car is warmed up and test drive it for at least 10 miles . That way if it breaks down , I won't have to go through the whole process again , which it will be on them . They however did loan me a 2013 328i which I'm grateful for cause they probably knew I smell something fishy is going on . At first when i asked for one, they told me they had no loaner cars and that my warranty didn't cover loaners but after all this fuss they didn't hesitate to give me one.

just dont let them intimidate you. Always act like u deserve everything otherwise u will complaint with BMWUSA

My warranty has expired for over 3 yrs and still get a free loaner (2013 model too) everytime i get my oil changed.

[Snyperx]

Originally Posted by GoRomeo

My warranty has expired for over 3 yrs and still get a free loaner (2013 model too) everytime i get my oil changed.

Same here with my dealer. I have a 2006 325i with 85k and still get a loaner WHEN I take it to the dealer.