540i engine failsafe

[rf900rkw]

Automerge


Okay, lets start simple. Voltage test at the MAF. Don't care if it's plugged in or not for this test. As always, do not damage the pins.

Pin 4 RT/GN to Pin 5 GE

Pin 4 to engine ground

Pin 5 to engine ground.

Also, exactly which O2 sensor took the hit?

[imola38]

Those 02 sensor wires dangling like that could be causing all sorts of havoc. Is this car an auto or manual trans? If it's auto you could have damage to the transmission harness as well. If EWS doesn't see a Park or Neutral position, it won't allow the starter to engage.

Are you getting any codes in the transmission through DIS? Does it show all gear positions?
Check ALL fuses in the glovebox as well. Start with the simple stuff first. If all fuses are good, it's time to start checking continuity.

Sent from my iPhone while driving

[nlacey]

As I suspect...you've triggered the EWS or Electronic Immobilization IMO. This is most likely why you clear the codes, it seems ok and then won't start. As I stated earlier, you've pissed her off by tinkering with sensitive components.

From the Bentley: "Replacement EWS control modules or DME control modules must be electronically aligned to each before the vehicle will start. This requires the use of the bmw service tester (DIS-plus, GT1, or MoDiC). Without alignment, the engine will not crank (for example swapping a known good DME control module into another vehicle for test purposes will result in a no crank situation). In the EWS system, the ignition key is embedded with a computer chip (EEPROM) and coded. The key communicates with the vehicle using a transponder in the key and a ring antennae surrounding the steering lock cylinder. Up to 6 replacement keys are permissible. Only an authorized bmw dealer can provide replacement keys."

You could also have a faulty ring antennae but I'm not sure of your y/m. It only comes with EWSII cars so it may not be applicable.

You may have to bite the bullet on this one and see if a local Indy can override the immobilization circuit...my apologies that I can't be more helpful.

ECU...Engine Control Unit?? Same as ECM??? If so, it may be faulty or you have a short somewhere in the system IMO.

As you can tell, I can't stop thinking about this issue. It seems odd that she was starting and then, all of a sudden, you can't get her to start. The codes point to your Drive-by-wire system, that is a given but the start/no-start issue can be frustrating. I know these cars have sophisticated anti-theft systems and your troubles may very well be related to a security coding. :popcorn

Sent from my Transformer TF101 using BF.com

Maybe you erased the key from the EWS memory somehow??? Just gonna keep tossing them out there...

How far up the harness did you check from where those wires had been pulled? It looks like they had been pulled pretty hard so it could have pulled the wiring farther up the harness, which could be the root cause of your plethora of codes. You're gonna have to pull out a big ole can of whoopass and spend some time tracking down those electricals...

Sent from my Transformer TF101 using BF.com

I did piss off the EWS somehow...but it's been remedied (i think). Somehow I may have cause it to think I was tampering when I unscrew it from under the dash. I didn't unplug it, so I figured it wouldn't do any harm. Hell to be honest I didn't even know what it was when I unscrewed it....I was just trying to get to the pedal pot connector and make sure it was plugged in tightly. Either way...after a freshly charged battery and a quick DME-EWS realignment in DIS, I haven't seen the code again and the car fired right up. For reference purposes I have DME 7.2 and EWS 3.3. So for right now the EWS issue is gone. I am curious why the car seems to only start after I disconnect the battery and reconnect. It will run with a rough idle (flash engine failsafe after 5 seconds) and if I shut it off...sometimes it restarts...sometimes it wont.

In reference to the wires...I spliced new connectors on them and reconnected the other day. I only had on jack so the clearance wasn't that great. Tomorrow I'll go buy some ramps so I can really get up under there and see if any other carnage occurred.

Automerge


Okay, lets start simple. Voltage test at the MAF. Don't care if it's plugged in or not for this test. As always, do not damage the pins.

Pin 4 RT/GN to Pin 5 GE

Pin 4 to engine ground

Pin 5 to engine ground.

Also, exactly which O2 sensor took the hit?

I'll get on it first thing in the morning. Both post cat sensors wires were stripped from the harness side. The sensors themselves stayed in the exhaust and wasn't damaged directly (i think). I have a grasp on checking voltage...but when it comes time for me to check continuity...my multimeter doesn't have the audible option.

Those 02 sensor wires dangling like that could be causing all sorts of havoc. Is this car an auto or manual trans? If it's auto you could have damage to the transmission harness as well. If EWS doesn't see a Park or Neutral position, it won't allow the starter to engage.

Are you getting any codes in the transmission through DIS? Does it show all gear positions?
Check ALL fuses in the glovebox as well. Start with the simple stuff first. If all fuses are good, it's time to start checking continuity.

Sent from my iPhone while driving

The car is a manual trans. No trans codes. I checked the glovebox fuses and the fuses pack behind the DME. Everything looked ok...nothing blown. I agree....looks like it will be a long day tomorrow checking voltages and continuity.

[rf900rkw]

Just to make sure, is the O2 wiring repaired fully?

[nlacey]

Just to make sure, is the O2 wiring repaired fully?

Correct. I'll double check the connections and wiring color codes. Would replacing the whole harness from the DME to the sensors make sense? It would rule out and shorts right? Because I'm not sure how long my wife had been driving the car with them dragging like that. Now that I think about it...when the car died and went into failsafe, I was driving over one of the cables they put across the roadway to count traffic. Seems like the second I hit that small bump the engine failsafe came up and stranded me on the side of the road. So...maybe it caught it and snatched the wires hard enough to damage something further up the harness...or made contact with something enough to short out out?

[rf900rkw]

That's pretty much what I'm thinking... the 12V heater line got crossed to the sensor return plane. Need to prove if that is the case, if it is STILL the case, where the damage was done, and how much. Tracing electrical like this is like maneuvering through a complicated maze with the only directions being very cryptic riddles. Each turn can not be attempted until the previous is solved. The testing at the MAF I suggested is to check the +5V and sensor return planes. I'm expecting to find excessive voltage on the return.

[nlacey]

That's pretty much what I'm thinking... the 12V heater line got crossed to the sensor return plane. Need to prove if that is the case, if it is STILL the case, where the damage was done, and how much. Tracing electrical like this is like maneuvering through a complicated maze with the only directions being very cryptic riddles. Each turn can not be attempted until the previous is solved. The testing at the MAF I suggested is to check the +5V and sensor return planes. I'm expecting to find excessive voltage on the return.

Its a rainy day here in Georgia...so i'll have to get to it tomorrow or whenever it stops raining. Also..when the car first started doing this...I check the thermostat connection and the harness on the thermostat was burned up pretty good. I bought a new thermostat and cleaned up the coolant crust on the plug. I also checked the DME for corrosion..etc. Nothing showed on the DME side. So maybe I should also check the thermostat plug for 5v power and the return plate?

[ViolinARC]

Its a rainy day here in Georgia...so i'll have to get to it tomorrow or whenever it stops raining. Also..when the car first started doing this...I check the thermostat connection and the harness on the thermostat was burned up pretty good. I bought a new thermostat and cleaned up the coolant crust on the plug. I also checked the DME for corrosion..etc. Nothing showed on the DME side. So maybe I should also check the thermostat plug for 5v power and the return plate?

At this point, you are going to have to start checking most of your connections for continuity as it appears you have a short or ground fault (possibly several). As I stated...big ole can of whoopass!

[rf900rkw]

The thermostat heater isn't in the same circuits. It has 12V supplied and the DME supplies the ground. This works the same as the O2 heater circuits, same fuse even. Your problem appears to be in the +5V sensor circuits, several reading +5 when they should be close to 0.

[ViolinARC]

The thermostat heater isn't in the same circuits. It has 12V supplied and the DME supplies the ground. This works the same as the O2 heater circuits, same fuse even. Your problem appears to be in the +5V sensor circuits, several reading +5 when they should be close to 0.

[nlacey]

Automerge


Okay, lets start simple. Voltage test at the MAF. Don't care if it's plugged in or not for this test. As always, do not damage the pins.

Pin 4 RT/GN to Pin 5 GE

Pin 4 to engine ground

Pin 5 to engine ground.

Also, exactly which O2 sensor took the hit?

Excuse my ignorance but what does rt/gn and ge mean?

[rf900rkw]

Sorry, I meant to come back and expand on that once I verified my translations. It is the wire color.

RT/GN = Red with a Green stripe

GE = Yellow

[nlacey]

Sorry, I meant to come back and expand on that once I verified my translations. It is the wire color.

RT/GN = Red with a Green stripe

GE = Yellow

Oh ok.

Pin 4 to 5 read nothing
Pin 4 to ground 5v
Pin 5 to ground 5v

Also since I had it already unplugged I tested pin 1 and 2 to ground on the thermostat. I got 11.7v and 3.8v

[rf900rkw]

That's roughly correct on the thermostat heater. 12V supplied by a fuse, ground (modulated) supplied by the DME. But we need to concentrate on the 5V system, as you just proved it's got problems. You should have had

4 -5 5V
4 - ground 5V
5 - ground 0V

The two to engine ground are relative, as sensor return plane is not always at chassis ground potential. No matter that, you're sensor return plane is showing 5V, meaning it's not connected to ground anymore.

Now the real fun begins..... more in a bit. If you want to scope out the diagrams, This is the root diagram we'll be using.

Okay at the DME itself:

All referenced to engine ground. All tests done with the connectors plugged in and key on. All *SHOULD* be close to zero. A straightened paperclip is useful for probing the in-place (called backprobing) connectors.


Colors:

BR Brown
BL Blue
RT Red
GR Green
GE Yellow
SW Black
WS White
VI Violet

Connector location
And here
And here

Connector X60003

Pin 23 GE
Pin 6 BR

Connector X60002

Pin 8 GE
Pin 9 GE
Pin 10 GE/RT
Pin 11 GE/BL

Connector X60001

Pin 4 BR
Pin 5 BR
Pin 6 BR

Connector X60005

Pin 5 BR

[nlacey]

Ok....here we go. LoL took me a second to finally realize it would be easier to probe if I took the hood thing off the connectors.


Connector X60003

Pin 23 GE - 5v
Pin 6 BR - 0v

Connector X60002

Pin 8 GE - 5v my color was yellow and white
Pin 9 GE - 5v correct color code
Pin 10 GE/RT - 5v my color was solid yellow though
Pin 11 GE/BL - 5v



Connector X60001

Pin 4 BR - 0v
Pin 5 BR - 0v
Pin 6 BR - 0v

Connector X60005

Pin 5 BR - 0v

[rf900rkw]

All the BR wires are external grounds. Nothing there. The one Pin 23 is the other end of the MAF wire tested earlier, as a sanity check. The other four are the signal returns from the four O2 sensors.

Grumble... I was really hoping to find 12V on one of the O2 lines flooding the Sig Rtn plane. Not the case.....


I need to consider a bit. Does your meter have amp capability?

[nlacey]

I'm not sure. I know nothing about multimeters. Here is mine below
I'm also going to get the car up on ramps and inspect the pre cat o2 sensors today.

[rf900rkw]

I hope you haven't been testing like that. The black lead goes to the center COMmon post. It does have the proper settings for anything we'll need.


Edit:

For the tests done so far, the leads in that position will still work. The ground lead will just be reading through a 10A shunt.... won't matter at the level we're messing with.

[nlacey]

I hope you haven't been testing like that. The black lead goes to the center COMmon post. It does have the proper settings for anything we'll need.


Edit:

For the tests done so far, the leads in that position will still work. The ground lead will just be reading through a 10A shunt.... won't matter at the level we're messing with.

Just saw your edit. I had already changed the position and retested everything. Same values.

[ViolinARC]

[rf900rkw]

Unforch, the next step is involved, and has risk if done incorrectly.Thus I would prefer to do it over the phone realtime. PM sent.

[ShaunJ78]

I have the same issue with my e39. How did you resolve it?

[geargrinder]

Dude. You got answers in your own proper thread and seem to be not interested in them? I gave you a bunch of input, then asked several questions. Try replying to the conversations you start maybe before shotgunning demands into zombie threads?

And 5yr old zombie thread not really best route to get answers. If you look you'll see OP hasn't posted on this site since June of 2012. I'm guessing he's not gonna make a guest appearance just to help you out.

However you can note that Randy gave OP roughly the same advice we gave you in your own thread:

Many of those codes could have been caused by a low battery. And also possible ghost codes from the previous work and testing..

Step one, get a good hot battery installed. You may want to leave a low powered trickle charger on while you are working.

Step two clear codes from all modules. Clear adaptions from DME

Step three key off, key on for ten seconds (don't touch ANYTHING), key off for two, key on.

Step four attempt to start

Step five assuming no start, reread codes and report

So. Indeed. Maybe go back to your own thread and pick up where we left off.

[nlacey]

Randy was a God send for me. We ended up taking it offline and finished troubleshooting over the phone. My memory is horrible from 5 years ago...but I think we ended up having to re-ground the sensor return plane. My issues disappeared completely. Sorry I couldn't be of more help.

[KickingKangeroo]

I’m having this same exact problem and it’s been killing me. It’s been persisting for the last two weeks. Can you elaborate on what you mean by “regrounded the sensor return plane”?