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Engine cranks but does not start

Tiny
BOSSD1
  • MEMBER
  • 2005 AUDI A6
  • 3.2L
  • 6 CYL
  • AUTOMATIC
  • 95,000 MILES
So, long story short I had to drive the car one hour away to home without a camshaft position sensor as that is how I bought the car. As I was driving the car it kept cutting out randomly and the only way to keep it from stopping was keeping the gas pedal down even in traffic. I was forced to put the car in neutral and keep the pedal down, I also noticed the car was lagging with the acceleration and there was a lot of drag and it felt like there was a lot of power loss. Fast forward 30 minutes I noticed after I switched off the engine it wouldn't start and there was no crank for like 5-10 minutes it was as if the car was cooling down then it would start and crank and turn over.

So, fast forward I got the part "camshaft sensor" and fitted onto the car then I started the car and it turned on. So, the car was idling, and I decided to test each coil pack to see if the car would start shaking if I pulled any of them out. I pulled the first one and it didn't make much of a difference then pulled the second and third then the car was shaking a lot and it instantly cut out and wouldn't start again.

After days and hours of searching I noticed my crank case breather hoses was all broken so I replaced this as I suspected this was causing the no start, but this didn't help. I did however notice oil in the spark plug chambers and cleaned all 6 plugs and put in new spark plugs. Still no luck. I went and bought a fuel pump as I suspected that was the issue and replaced the old fuel pump. But still no luck.

Today I was checking with my multimeter if the crankshaft sensor wiring was getting any voltage and there was absolutely no reading, any other wiring within the engine was getting readings just not the crankshaft sensor wire.

so, to conclude.

Could this be my problem?
Is there any way I could find out if it's something else before opening it up?
Any suggestions on what to try?

I ran a diagnostic tool and here are some things I got back from it.
please be aware my battery is not good, and I have a spare car to charge it while I run these diagnostics, so some codes are due to battery.
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Thursday, March 10th, 2022 AT 3:33 PM

23 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,716 POSTS
Hi,

If the crankshaft position sensor is bad, you won't have spark to the plugs. Check for that.

Next, these vehicles are very sensitive to voltage issues. I would replace the battery to see if that makes a difference.

Here is a link that explains how to check for spark:

https://www.2carpros.com/articles/how-to-test-an-ignition-system

Let me know what you find.

joe
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Thursday, March 10th, 2022 AT 7:38 PM
Tiny
BOSSD1
  • MEMBER
  • 15 POSTS
I have another car to jump this.

I still haven't got the crankshaft sensor.

My plugs do have spark when I checked them.

Here is a video of me trying to start it today:

https://youtube.com/shorts/EJmEHSj-sFQ?feature=share
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Friday, March 11th, 2022 AT 9:41 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,716 POSTS
Hi,

I watched the video. It could be related to voltage. However, at this point, I need to know the actual codes that were found. Also, I need to know if when it was scanned, if you used a scanner able to read the can-bus.

Let me know.

Joe
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Friday, March 11th, 2022 AT 1:01 PM
Tiny
BOSSD1
  • MEMBER
  • 15 POSTS
The scanner I used is worth  1000s I’m sure it will have that. What is a can bus is there an option for that?

Below are some codes it gave.
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Saturday, March 12th, 2022 AT 2:47 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,716 POSTS
Hi,

The pics above indicate CAN-related codes. Specifically, the U codes and ones indicating "Databus".

Basically, the acronym CAN stands for controller area network. In other words, it is a few wires that connect the different computers/modules together via a few wires.

You have codes indicating several modules are unable to communicate. My first reaction to this is the CAN interface has failed and is causing an inability for the modules to communicate. If it was one specific module, for example, the U0111 battery energy module A, that module would be my first suspect. However, this vehicle has communication loss with several different modules. I don't feel all would have failed at the same time.

The controller is located under the dash on the passenger side and not easily reached. I attached the only pic I could find below.

You may want to locate it and inspect wiring and connectors for any damage or corrosion. However, make sure the battery is disconnected prior to unplugging it.

Please understand, I could be wrong when saying this is the issue. However, I am basing it on a few past experiences that were similar to what you are dealing with. The start and stall issue is the one thing that stood out to me.

Let me know if this helps.

Joe

See pic.
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Saturday, March 12th, 2022 AT 1:03 PM
Tiny
BOSSD1
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  • 15 POSTS
Which one is the part I’m looking for? This is all at the passenger's side. I’ve removed the glovebox and made it easier to access.
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Saturday, March 12th, 2022 AT 5:02 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,716 POSTS
Hi,

See pic below. If you get me the part number from it, I can confirm for you. However, that appears to be it.

Let me know.

Joe
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Saturday, March 12th, 2022 AT 5:09 PM
Tiny
BOSSD1
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https://www.google.com/search?q=4f0907468D&rlz=1CDGOYI_enGB942GB943&oq=4f0&aqs=chrome.2.69i59l3j69i57j69i61j69i60.7396j0j7&hl=en-GB&sourceid=chrome-mobile&ie=UTF-8

That comes back as gateway control module.
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Saturday, March 12th, 2022 AT 5:10 PM
Tiny
BOSSD1
  • MEMBER
  • 15 POSTS
Part Number: 4f0907468D.
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Saturday, March 12th, 2022 AT 5:11 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,716 POSTS
Hi,

That's it. Take a look through the attachments below. They are the description and test procedures for it. Let me know if you are comfortable doing it

Joe

See pics below.
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Saturday, March 12th, 2022 AT 10:06 PM
Tiny
BOSSD1
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How do I locate central termination resistor? Is it the pins? There is only 26 pins do I have to open it up?
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Sunday, March 13th, 2022 AT 6:53 AM
Tiny
BOSSD1
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  • 15 POSTS
I have opened it up.
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Sunday, March 13th, 2022 AT 7:09 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi,

I have no schematics for the circuit board. As far as the termination resister inside it, I have no way to locate it. I'm sorry about that.

Let me know.

Joe
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Sunday, March 13th, 2022 AT 3:43 PM
Tiny
BOSSD1
  • MEMBER
  • 15 POSTS
Not sure what I'm looking at, could you point out from the images what needs to be tested? Or do I just go and purchase a new part?

Thanks
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Sunday, March 13th, 2022 AT 3:45 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,716 POSTS
Hi,

The test procedures I listed above are what a shop would use for testing. That's what I have. Take a look at them and let me know if you understand them.

Let me know.

Joe
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Sunday, March 13th, 2022 AT 4:22 PM
Tiny
BOSSD1
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  • 15 POSTS
I do not understand them unfortunately.
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Sunday, March 13th, 2022 AT 4:23 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,716 POSTS
Basically, they explain what to test for excessive resistance. It's hard for me to explain via the internet, without being there.

Joe
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Monday, March 14th, 2022 AT 5:38 PM
Tiny
BOSSD1
  • MEMBER
  • 15 POSTS
Alright I guess for now we at a stalemate best I can do for now is find someone that can test the module for me as I haven’t got a clue what I’m testing.

Thanks for the help so far.
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Monday, March 14th, 2022 AT 7:06 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,716 POSTS
Hi,

I totally understand. I miss the days when things weren't so Indepth. LOL

Regardless, let me know what you find or if I can help in any way.

Take care,

Joe
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Monday, March 14th, 2022 AT 7:53 PM
Tiny
BOSSD1
  • MEMBER
  • 15 POSTS
Hi,

I’ve found something interesting, so I decided to check if there was compression and on the right-side bank all cylinders had 0 compression while the ride side 1-3 had 150.

Is this sounding like bad news.

I think timing has slipped when I pulled out the spark plugs.
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Wednesday, March 16th, 2022 AT 11:26 AM

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