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Pelican Technical Article:

Reading E39 Fault Codes

Kerry Jonsson

Time:

2 hours2 hrs

Tab:

$0 to $300

Talent:

**

Tools:

Scan tool, Code reader

Applicable Models:

BMW 525i Sedan/Wagon (2001-03)
BMW 528i Sedan/Wagon (1997-00)
BMW 530i Sedan (2001-03)
BMW 540i Sedan/Wagon (1997-03)

Parts Required:

Code reader

Hot Tip:

Do not clear fault codes until you think you have repaired the problem

Performance Gain:

Knowledge of needed repair causing code

Complementary Modification:

Record fault code and description before clearing

The impetus to control motor vehicle emissions, driven by the air quality needs of major metropolitan areas, has lead to 5 decades of engineering innovation in the design of vehicle propulsion technologies. Because California cities (particularly Los Angeles) were hardest hit by the proliferation of vehicles and their emissions, starting in 1961 the California Air Resources Board (CARB) has been at the forefront of setting engineering standards for vehicles sold in California, then in the United States and now for the world automotive industry.

Modern vehicle engine operations and emissions (including evaporative losses from the fuel tank) are extensively controlled via a digital microprocessor, known as the engine control module or ECM. Feedback systems, relying on sensors, allow the ECM to precisely control fuel / air mixture, spark timing and other functions. Of the many sensors on the engine and the vehicle, the primary ones are oxygen sensor(s); which monitor the combustion efficiency of the engine, and the knock sensor(s); which "listen" for engine knock or pinging. The input signals from these sensors are used by the ECM to adjust fuel mixture and spark timing.

Computer control of the engine operations allow two benefits in addition to a precise air fuel mixture and, therefore, lower emissions. The computers can be programmed to detect faults (diagnostic trouble codes or DTCs) in their own operations, and the ECM can store this information and illuminate a malfunction indicator light (MIL), often called the Check Engine light or malfunction Indicator lamp, on the instrument cluster. The stored faults can be viewed later for diagnosis and repair.

Diagnosis of modern vehicle performance faults start with gaining access to DTCs stored in the ECM. Start by looking for the 16-pin OBD II plug (diagnostic link connector or DLC) under the dashboard. By law, it is always located within reach of the driver.

Once the diagnostic scan tool is connected to the DLC, follow instructions on the scan tool screen. These usually include: Select diagnosis program. Select correct vehicle (scan tool should find this automatically). Interrogate and record DTCs (fault codes) present in ECM memory.

In many cases, it is best to clear DTCs, then drive the vehicle and retest. Follow diagnostic and repair instructions on scan tool screen. DTCs for the vehicle power train, as standardized by the American Society of Engineers (ASE), begin with a P and are followed by 4 digits. (They are also referred to as P-codes.) During testing, the scan tool displays each P-code and a brief description of the fault. There are different kinds of fault indicated by DTCs: Plausibility. If a sensor's output value is outside the expected range, the signal from the sensor is considered not plausible and a fault is set. Power, ground and continuity. If power or ground is missing or continuity is lacking in a particular circuit or system, a fault is set. Fault in the sensor or module. If a sensor or module tests defective, a fault is set.

You should note that even though the scan tool displays specific DTCs, additional diagnosis is advisable. For example, if a DTC indicates a non-functional oxygen sensor heater, the simple explanation may be a blown fuse. In other words use common sense and do not ignore the obvious when diagnosing problems.

Early BMW E39 models have two data link connectors (DLCs) to connect a scan tool to.
Figure 1

Early BMW E39 models have two data link connectors (DLCs) to connect a scan tool to. If you are using a generic scan tool, you can connect to the 16 pin OBD II connector (green arrow) at the lower left side of the dashboard (driver side). Be sure to reinstall the plastic cover (yellow arrow) when complete. On some models, this can mess up communication on the 20 pin connector if left off. Late BMW E39 models may only have a 16 pin OBD II connector. Once they moved to this style of plug, you get full access to all the systems when using an advanced BMW scan tool.

If you are using a BMW scan tool or a Peake code reader, you can connect to the 20 pin connector (green arrow) on the right side of the engine compartment.
Figure 2

If you are using a BMW scan tool or a Peake code reader, you can connect to the 20 pin connector (green arrow) on the right side of the engine compartment. 

Connecting a Scan Tool to 16 pin OBD II connector:
Working at dashboard, open OBD II connector access door.
Figure 3

Working at dashboard, open OBD II connector access door. (green arrow) Turn lock using flathead screwdriver and remove door from dash.

Plug the scan tool into OBD II connector.
Figure 4

Plug the scan tool into OBD II connector. Follow directions supplied with scan tool to interrogate the ECM fault memory. Read the fault codes, diagnose the problems, then clear fault codes when complete.

Connecting a Scan Tool to 20 pin BMW connector:
Working at right side of engine compartment, unscrew the 20 pin BMW connector lid.
Figure 5

Working at right side of engine compartment, unscrew the 20 pin BMW connector lid. (green arrow).

Plug the scan tool into the 20 pin BMW connector.
Figure 6

Plug the scan tool into the 20 pin BMW connector.

Follow directions supplied with the scan tool to interrogate the ECM fault memory.
Figure 7

Follow directions supplied with the scan tool to interrogate the ECM fault memory. Read the fault codes, diagnose the problems, then clear the fault codes when complete. You can see that when using the 20 pin BMW connector, you have access to all systems, not always the case the 16 pin OBD II connector.

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Comments and Suggestions:
Greg Comments: I contacted the company I posted the link for and they will exchange the ECU for 475 and I have to send them my EWS and key, or they will repair the one I have for about 700. Much cheaper than I thought. I have a couple more question though... The car was a repo and when the guy picked it up there was no battery. He jumped it and drove it about 10 miles like that. He put in a battery when I purchased it, but it is a 650ca and all of the BMW recommended replacement batteries that I have seen are 850ca or more. I was told earlier today that these cars pull a lot more from the battery than American cars and that a smaller battery could cause serious problems.. Any truth to this? Also, do the 2000 models need to have the battery registered? I will say that the work I have done on this car has been the easiest, hassle free mechanic work I have ever done, I have never been able to change plugs and/or coil packs from hood up to hood down in under 15 minutes on any other vehicle I have owned. It takes almost that long to get to the coil packs on my Envoy. However, I have to say that I have heard the weirdest stuff about BMWs like the battery thing and not to change grades of fuel or use fuel system cleaners. So far one of the oddest things I have seen is that you can stick a rolled up paper in the fan and stop it. That's actually how I was told to test it to make sure its good.
October 27, 2016
  Followup from the Pelican Staff: You should put the correct battery in, as to not overload the alternator. The battery will not have to be registered. - Nick at Pelican Parts  
Greg Comments: Thanks for getting back to me, Nick! I was thinking that might be the issue. So my next question is, what about having a new one programmed to work with my cars EWS and whatever else it needs to be synced up with? I have read on a few forums where people have bought used ones on EBay with the matching EWS and a key and claim they work fine. I assume that the keys are universal and programmed to work with the rest of the system? I also found this site who claims to be able to repair your current ECU and send it back with a 5 year warranty. http://www.ecudoctors.com/our-ecu-dme-repair- process.html. Thoughts?
October 26, 2016
  Followup from the Pelican Staff: ECU repairs are a good option. Most times the part is returned with software and working normally. I haven't installed used parts, so I can't offer much advice there. BUT - you can try to have someone with the right tool program a used one. It may work.- Nick at Pelican Parts  
freddie Comments: dear sir i have a 1997 540i my car had set for a spell an i had to put the charger on it now i have no haed lites no blinkers no dash lites also fefore i charged the battery the lefttail lite was lit whith no one in the car what should i look for thank you
October 20, 2016
  Followup from the Pelican Staff: Sounds like the charger may have blown a fuse or damaged a control module. Start by checking the fuses and the vehicle for fault codes. - Nick at Pelican Parts  
Greg Comments: I recently purchased a 2000 528i. I don't know if they all have the M I'm told this is a sport package Also no clue if that matters, but it has a few issues so I had it hooked up at 2 parts stores and both places got the same fault codes and were unable to tell me anything about them. The P0101 MAF AND 0443 EVAPwere easy to figure out but there are 3 that I can't find anything on: 1770 CAN Torque Interface which is on the printout 2x, 0601 Internal Control Module Memory Check Sum Error,and 1542 Pedal Position Sensor Electrical. The 0601 makes me think something is up with the ECU and with 1770 I get the feeling things aren't communicating as they should which could lead to other systems being off, right? I pulled the ECU and checked for signs of moisture leakage and dirt but it was very clean so my next guess would be a relay assuming things went bad under normal conditions. There is another side of this issue though, which is that the previous owner seemed to think it was a sports car so he launched it several times and he has a bad history of trying to put turbos on cars that they shouldn't be on and playing around with the ECU in an attempt to up the performance. SO.... before I sink a ton of money into wrong stuff for my DIY project I wanted to seek some advice from someone who may actually be able to fill me in or lead me in the right direction. Thanks in advance for any help
October 17, 2016
  Followup from the Pelican Staff: If you have a checksum error, the control module is faulty. End of story. You can confirm it has the right power and ground feeds, after that replace it. Once replaced, see what codes return and repair what is necessary. You may also have faults stored in other control modules. - Nick at Pelican Parts  
John B Comments: My 2001 e39 530I I have owned since new now w/134K mi. suddenly when starting to first shift into Drive, will balk at the lever going into Dr, even with the shift trigger engaged. Runs, drives perfectly, any suggestions?
July 24, 2016
  Followup from the Pelican Staff: is it a delayed engagement into when first put into drive? That can be due to a pressure loss or fluid leak, internal. - Nick at Pelican Parts  
Jim Comments: How to reset a check engine lite 1994 525i
June 20, 2016
  Followup from the Pelican Staff: This article should help you:

http://www.pelicanparts.com/BMW/techarticles/Mult-Code_Reading/Mult-Code_Reading.htm - Nick at Pelican Parts
 
Walguy2000 Comments: Thanks Nick door latch was wore out and we fixed it thanks again
November 11, 2015
  Followup from the Pelican Staff: Thanks for the follow up. - Nick at Pelican Parts  
Walguy2000 Comments: My son has a 1998 528i and on the dash it shows that the drivers door is always open and sometimes while he is driving the interior lights come on.
Where is this sensor located at. or is any thing we can do
November 8, 2015
  Followup from the Pelican Staff: Likely an issue with the door latch hook. Check the switch in the hook the door latch attaches to when closed. - Nick at Pelican Parts  
Keewee Comments: Hi, I have a fault code that says "Choke valve, control fault" What is this referring to. On my C310 scan tool is under ABS number 26, my local garage is number 38 on their system. I forgot to mention that the traction control light comes & stays on. When I restart the car it disappears but is logged. Cheers Rob
July 23, 2015
  Followup from the Pelican Staff: What vehicle and what system was the code retrieved from? - Nick at Pelican Parts  
noseman Comments: Hey nick ive got a 98 538i and its missing real bad. I replace the spark plugs but not thr coils. Can they be the cause? The miss has gotten gradually worse.
December 4, 2014
  Followup from the Pelican Staff: Coils are very common. Be sure you have good fuel delivery and compression. - Nick at Pelican Parts  
Roy Comments: Nick. I am taking your advise. But I just want to know in my mind a question that bothers me abt. this. How can a part that is factory sealed and has but one purpose to "fire" once sealed, etc. go bad just sitting under the seat? If the wiring is bad, ok, if a loose connection, ok, but a sealed unit! I think of it as an unexploded shell lying in a dry place for years , and then going bad ! I realize it is most likely bad , BUT ! thanks again roy
December 26, 2013
  Followup from the Pelican Staff: The parts fail, just the way it is. If resistance on the circuit changes even the slightest, the control deems the part faulty. - Nick at Pelican Parts  
Roy Comments: Thanks Nick,
I have a code reading tool which has one fault code , and it comes up 0.6 which the book i have says it is the " passenger seat belt pretensioner . The pretentioner has never been fired nor has the bags ever deployed. Trying to reset this Air Bag light on the warning lights will only work for a short period of time and then back on. 2 mins or less Do you have any recommendations /
December 21, 2013
  Followup from the Pelican Staff: The pretensioner doesn't have to be fired to set a fault. it or the wiring to it can be faulty. I would replace it, as it is the most likely cause of the light. - Nick at Pelican Parts  
Roy Comments: Nick, the video i saw but can not find again shows a fix that turns off the air bag light but does not disable the air bags capability. Have you heard of this? thanks
December 21, 2013
  Followup from the Pelican Staff: This is a bad idea. What you are referring to, tricks the SRS module into thinking the faulty part is good. You do not want to do this. - Nick at Pelican Parts  
Roy Comments: I heard of a video that shows how to fix the false airbag lite by inserting some resistors into the plug under the seat. do you know where i can find that ? thank you Roy
December 20, 2013
  Followup from the Pelican Staff: I would advise against bypassing any safety features of your vehicle. - Nick at Pelican Parts  

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Page last updated: Wed 12/7/2016 02:06:23 AM