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Electric Water Pump Testing
 
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Pelican Technical Article:

Electric Water Pump Testing

Nick Czerula

Time:

3 hours3 hrs

Tab:

$200

Talent:

*****

Tools:

Test light, voltmeter, back probes

Applicable Models:

BMW 525i/xi Sedan (2004-07)
BMW 528i xDrive Sedan (2009-10)
BMW 528i/xi Sedan (2008-10)
BMW 530i/xi Sedan (2004-07)
BMW 530xi Wagon (2006-07)
BMW 535i xDrive Sedan/Wagon (2009-10)
BMW 535i/xi Sedan (2008-10)
BMW 535xi Wagon (2008)

Parts Required:

Water pump, hoses, engine coolant, electrical connector seal

Hot Tip:

Work with a cool engine

Performance Gain:

Car will cool down again and remedy fault codes

Complementary Modification:

Change thermostat

On BMW E60 models with the N52 or N54 6-cylinder engine, the coolant pump is an externally mounted electric pump bolted to the right front of the engine block. Using an electric pump (as opposed to the engine-belt-driven variety) helps engine cooling efficiency and longevity, as the pump can operate regardless of whether the engine is running or not and also regardless of engine rpm. For example, a low rate of flow is maintained during cold start situations to help the engine warm up rapidly, while a high flow rate can be used for rapid cool-down, such as when the engine is shut off.

The electric coolant pump is controlled by the engine control module (ECM). Engine load, temperature, operating range and other factors are used by the engine management system (DME) to determine coolant pump operation and speed. The pump also has self-diagnostic capabilities. Fault codes for the following conditions are stored in the ECM and can be used for diagnosis:

  • Pump impeller speed deviation
  • Pump shaft stiffness or obstruction by foreign object
  • Incorrect water / coolant mixture
  • Air the cooling system

When a coolant pump begins to fail, you'll notice that the car tends to overheat at low engine speed, such as sitting at a stoplight. When you accelerate, the engine temperature will drop. Now, this is not always indicative of a coolant pump failure, but a good starting point. You may also want to try squeezing the top radiator hose with the engine warmed up and running. You should feel pressure build up on the back of the hose and surge once it is released. If you feel no pressure, it's a fair bet that the coolant pump is failing.

The most common problem with the BMW electric coolant pump is a fault code for coolant pump volume. This fault code indicates the coolant pump is running at a speed lower than desired by the DME. This can be due to a broken impeller, a seized motor or faulty wiring. In this article, I'll go over the steps involved with testing the BMW electric coolant pump.

If you remove the electric coolant pump from your E60 and plan on reinstalling it, store it with the coolant inside, otherwise it will corrode and fail shortly after reinstalling it. Always replace aluminum fasteners each time they are removed and never reinstall a questionable coolant hose.

To do any work on the cooling system, wait until the engine has cooled off.

Keep in mind that when your car was serviced before, parts may have been replaced with different size fasteners used in the replacement. The sizes of the nuts and bolts we give may be different from what you have, so be prepared with different size sockets and wrenches.

Protect your eyes, hands and body from fluids, dust and debris while working on your vehicle. If you're working with the electrical system, disconnect the battery before beginning. Always catch fluids in appropriate containers and properly dispose of any fluid waste. Recycle parts, packaging and fluids when possible. Do not work on your vehicle if you feel the task is beyond your ability.

Vehicle models change and evolve, as they grow older, so the vehicle shown in our illustrations may vary slightly from yours. If something seems different, let us know and share your info to help other users. Do you have questions or want to add to the article? Leave a comment below. When leaving a comment, please leave your vehicle information.

This can be a tough part to diagnose as it is tucked away and behind many components.
Figure 1

This can be a tough part to diagnose as it is tucked away and behind many components. Traditionally the coolant pump was located at the front of the engine (green arrow). Electric coolant pumps (yellow arrow) are located on the lower right side of the engine.

The subject vehicle I had the opportunity to work with was a 535xi that overheated and the check engine light was on.
Figure 2

The subject vehicle I had the opportunity to work with was a 535xi that overheated and the check engine light was on. There were multiple fault codes stored. However, we will focus on the coolant pump faults in this tech article. Fault codes 2E81 speed deviation and 2E82 cutoff were stored (green arrows).

Before beginning with any fault code, I check the frequency of the fault.
Figure 3

Before beginning with any fault code, I check the frequency of the fault. This shows if it has been ongoing or intermittent. This data also shows the coolant pump speed (red arrow) along with the DME desired coolant pump speed difference (blue arrow). This data confirms the pump is not moving. Now it is up to me to figure out if the pump is fautly. The DME is haywire or it's a wiring issue. Your scan tool may not have this data, if it is not an advanced model. That is OK, you still have the fault code, so you can still diagnose the pump.

When working with late model BMWs, it is recommended you attach a vehicle power supply.
Figure 4

When working with late model BMWs, it is recommended you attach a vehicle power supply. This prevents the battery from becoming discharged and maintains a steady system voltage. I have the positive (red arrow) and negative (blue arrow) leads connected to the under hood jump start terminals.

Now it's time to attempt to activate the pump.
Figure 5

Now it's time to attempt to activate the pump. My scan tool has an option to run the pump at varying speeds (green arrow). If you do not have this option in your scan tool, turn the ignition to the ON position, but do not start the engine. Then set the heat to HIGH. This will activate the coolant pump as well.

Once you activate the pump, listen for it running and check the coolant reservoir for signs of coolant flow.
Figure 6

Once you activate the pump, listen for it running and check the coolant reservoir for signs of coolant flow. Coolant will flow out of the small hole (green arrow) in the reservoir when the pump is on. If a stream of coolant does not come out, it is not running enough to pump coolant. A quick tip: if you hear what sounds like a dying frog, it could be a seized pump. I hear pumps make this sound time and time again when attempting to activate them.

Now that we have either confirmed there is or isn't coolant flow, we have to test the electrical circuits.
Figure 7

Now that we have either confirmed there is or isn't coolant flow, we have to test the electrical circuits. The problem is access. Our subject vehicle is a xi (all-wheel drive). That makes getting to the connector even harder. The connector (green arrows) can just be seen between the front axle support and the steering rack. I am going to show you how I accessed the wiring, from the top of the engine.

This is a wiring diagram from our subject vehicle.
Figure 8

This is a wiring diagram from our subject vehicle. The connector color and wire sizes (green arrow) match up with what I expected. You can start by checking the fuses, but I prefer to just go right to the circuit and testing there. Keep in mind that your wiring will likely vary. Double-check it with the latest wiring from a repair manual. The challenge that remains, even with access to some wires up top, is access to the ground. You will have to check the ground at this connector. Connect a DVOM to battery negative (-) and to the large brown wire. Your DVOM should read around 0 volts. Once you have a reading, use a test light to battery positive and touch your DVOM test lead to load the circuit. It should hold steady around 0 volts.

Working at the front of the cylinder head, I found the wiring harness that came up from the coolant pump.
Figure 9

Working at the front of the cylinder head, I found the wiring harness that came up from the coolant pump. There were three possible wire looms housing the wires I needed to test. I carefully opened each one and inspected them. I found the main power feed (red arrow) in one loom and the switched power feed and BSD (bit serial data) line (green arrow) in another. First I tested the main power feed. It is a battery positive (+) wire and has power all the time. The wire had battery volts and held steady when I load tested it. I can now move onto the next wires.

In the next loom, the switched power feed (green arrow) and BSD line (red arrow) were housed together.
Figure 10

In the next loom, the switched power feed (green arrow) and BSD line (red arrow) were housed together. There are two possible switched power feeds, (two orange wires). They are both the same voltage, battery positive (+) and had power with the key in the run position with the engine off and held steady when I load tested it. I can now move onto the BSD wire.

The BSD line is the control circuit for the pump.
Figure 11

The BSD line is the control circuit for the pump. The DME sends this digital control signal to the pump to control speed.

Testing with a DVOM, the circuit should be about 8 volts.
Figure 12

Testing with a DVOM, the circuit should be about 8 volts. Now, this tells me it MIGHT be ok. I would sway on the side of it being OK, however with a digital signal, it is best tested using a labscope. If all you have is a DVOM, I would be OK trusting the 8 volts and moving on, as the circuit appears to be OK.

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Comments and Suggestions:
Smokinaces87 Comments: 2007 bmw 530xi,new pump and thermo and still nothing from the pump. I was told and see on the enter webs that the Fuze needs checked....I just don't know where the Fuze is,does anybody know of this issue?
May 19, 2017
darthurwilson Comments: I am using a BMW electric water pump on my hot rod. I connected 12vdc+ to #1 wire. 12vdc- to #4 wire.
If I hold a 12vdc+ to #2 connector wire for 3 seconds and release it the pump runs at a slow speed.
If I leave #2 connected to 12vdc+ continuously the pump runs at high speed.
Questions
1. Will I burn out the pump by having #2 connected continuously to 12vdc+ #1 wire shows 8-9 amps #2 wire shows 1-2 amps.
2 I read about having only 8 volts on #2 is this correct?
3.how does the BSD circuit on #3 work?- Is it and info signal to the dme or does it control the pump using a signal from the DME?
May 13, 2017
  Followup from the Pelican Staff: the BSD circuit is a data circuit, the DME controls the speed dependent on engine demand. There is no other data available from BMW other than that. I don't have info on wiring them to run on other engine. You shouldn't burn it out, it should be able to run at max RPM. - Nick at Pelican Parts  
Carl Comments: Hi Nick. Thanks for the response. I should clarify. The scan tool did give a water pump fault code I saw it say pump fault but did not ask him what the code was - he used the app EzDiag. Then, he went to check on the speed of the water pump but it said 0 rpm. Have you heard of anything like this before? Any idea what this mean? Thanks.
May 9, 2017
  Followup from the Pelican Staff: 0 RPM would mean the BSD line from the pump is faulty. The pump is likely no good. - Nick at Pelican Parts  
Carl Comments: My car is showing no signs of a water pump failure e.g., overheating. The scan tool cannot read the status of the water pump so it shows 0 rpm for the speed. Is my water pump bad and, thus, needs replacing to correct this malfunction? Or, is it an electrical problem that will still exist even after replacing the water pump. What do you advise. Thanks!
May 8, 2017
  Followup from the Pelican Staff: Your scan tool may not be able to display the data correctly. If the pump is running and there are no fault codes, I would not trust the data. - Nick at Pelican Parts  
Nelly Comments: Hey Nick thanks for your reply. Yes I have replaced the thermostat and all of the temperature sensors. I have put an infrared thermometer while the overheat code is present on the top radiator hose giving me a reading of just over 200 degrees and about 150 degrees or so toward the bottom hose. As a matter of fact just yesterday 4/25/17 I initiated the pump bleeding process again and it took about a whole hour for it to turn off by itself and it was 2 seconds on 2 seconds off consistently the whole way through.
Thank you so much for your time.
April 26, 2017
  Followup from the Pelican Staff: if getting too hot fault, possible wiring issue then. Especially if temp is correct and all parts have been replaced. Only thing other than wiring is the DME. - Nick at Pelican Parts  
Nelly Comments: Sorry I forgot to add that while the engine is running I get a steady consistent stream.
April 25, 2017
  Followup from the Pelican Staff: Thanks. - Nick at Pelican Parts  
Nelly Comments: Hello Nick. I have a question. I have a 2006 bmw 525i with the N52 engine. I get the "engine temperature too high" message within 10- 15 minutes of driving. I have changed the thermostat and all other temperature sensors and still get the overheat warning. During the electric pump bleeding procedure which I have done numerous times, turn ignition on, put heater up all the way with blower fan on low, press accelerator for 10 seconds, here's where my question gets tricky instead of a consistent stream of coolant I get 2 seconds of streaming then it stops for 2 seconds then it streams for two seconds then stops for two seconds and this happens consistently for way more than 12 minutes. After about 20 minutes of this consistent rhythm I decided to stop and try again and still got the same results. I checked the plug that goes into the pump which consist of 4 cables. Cables 1 and 2 both read 12v. The 3rd cable read 7. something volts. And the last is the ground. Is this consistent stop-and-go streaming during bleeding procedure a clear sign of a failing pump? I have also noticed that even without pressing the accelerator for 10 seconds as long as I have my heater on high and turn on the ignition the pump activates itself with the same stop and go streaming. Sorry this question was a little long. Thanks in advance for your kind reply.
April 24, 2017
  Followup from the Pelican Staff: The two second on and off is normal. The pump activating with heat on is normal.

Possible you have a faulty thermostat or coolant temp sensor. Have you confirmed engine temp when the fault is present?

- Nick at Pelican Parts
 
MarcZakhia Comments: Hi i have bmw x5 3.0 2007 i changed my electric water pump and thermostat as well at my garage everything was done when we did the scanner for the car after the repair the water pump speed is 150/ 1 minute is that normal or what? thankyou.
April 8, 2017
  Followup from the Pelican Staff: It depends on engine temp and DME controlled speed. Your scan tool should show what the DME is requesting , then compare that number to the actual value. - Nick at Pelican Parts  
Mike Comments: 2008 535i, has 2E7C BSD code. Car runs very poorly,other codes stored. 2E7C Goes away when WP is disconnected, but other codes still present and car still runs badly. Is it an internal short in the waterpump?
February 15, 2017
  Followup from the Pelican Staff: Likely the waterpump is taking down the BSD communication. I think a new waterpump and thermostat should fix the faults. - Casey at Pelican Parts  
BMW family Comments: Hi- I have a 2009 BMW 535i x drive and I have been noticing a leak. The car is not heating up or anything, and I know the water pump is working fine.. i also tested it to make sure and it is functioning fine, but I see a little leak near it, can the water pump be tightened/fixed or does it have to be replaced? Also, the car is not loosing pressure or showing symptoms so I'm not sure what this leak can be... any ideas?
January 22, 2017
  Followup from the Pelican Staff: I would pressure test the cooling system. Once under pressure you will be able to pinpoint the leak. Near the water pump are a lot of hoses and connections, any one of them can be leaking. Give The Pelican Parts parts specialists a call at 1-888-280-7799. They can figure out what part or repair kit you need.
- Nick at Pelican Parts
 
bob Comments: 2008 bmw 58xi. dealer sai needs pump. replace it. still won,t work. have both 12volt wires no8 volt . what tells ecu to turn pump on ?
July 28, 2016
  Followup from the Pelican Staff: Check the ground to the pump. The basic body module activates the pump. - Nick at Pelican Parts  
Paul Comments: I replace new pump from Continental for 2010 535i xDriver. Battery still alive, key outside the car. Apter I connect connector, when pump contact with frame, I hear soul like fuse blowout at contact point. And pump no work, scan show codes 2E83, 2E84, 2E85 DMC electric pump missing. Any info?
Thank.
June 7, 2016
  Followup from the Pelican Staff: Check the wiring harness for the pump. Sounds like it is shorted. - Nick at Pelican Parts  
Jofuss3232 Comments: I bled my system and coolant was squirting out, could it still be my pump?
April 12, 2016
  Followup from the Pelican Staff: Yes, or a leak in a different component. Pressure test the cooling system. - Nick at Pelican Parts  
Wes Comments: Well here it goes I'm working on a friends 09 325i her battery went dead. Replaced it , two days her battery was dead. Determined that the electric water pump won't shut off continually runs till the battery is drained. Anyway trying to research what actually controls the pump? If you have any info I would be extremely thankful
December 31, 2015
  Followup from the Pelican Staff: The article you commented on has information on how the BMW electric water pump works and how to test it on E60 models. http://www.pelicanparts.com/techarticles/BMW-E60/15-WATER-Electric_Water_Pump_Testing/15-WATER-Electric_Water_Pump_Testing.htm

E90 models are similar. - Nick at Pelican Parts
 
Bill Comments: IS there a simple way to test the electric pump on a 2008 BMW 535i while it is off the car? If so, can you use a D C voltage source to test it?
July 9, 2015
  Followup from the Pelican Staff: This article shows the only way I know of testing it. - Nick at Pelican Parts  

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Page last updated: Mon 5/22/2017 02:26:46 AM