Besides those that call Audi junk, who can help?

[carlton_fritz]

2013 Audi A4 Quattro 2.0T. Having issues with it not starting. Carista OBD2 says U0100 code, which always comes back when reset. The rest of the codes are



CAN Network gateway 01314
Ignition Authorization 00956, 01330
Instrument cluster 01314
Parking brake 334080, 331264, 331520, 460800
Engine 04533, 10577
Transmission 12551, 12554, 12562
Power steering 3158274


New Alternator, new battery. ~51,200 miles. Battery is in the trunk, under the spare tire and tool kit. Hook up jumper cables under the hood and the car fires right up. When started, car runs normal. I do not have tools to test everything, such as a multimeter. Wouldn't know where to test if I had one. By the time I am don't with this car, I will probably know how to build one.

[DJ_Critterus]

Saudis in Audis - YouTube

[carlton_fritz]

Required photo.

[Rodnok1]

Codes are meaningless without definitions.
Current or history also is needed.
Easiest thing to do would be test the battery, testing wise. A load test is in order especially if any of those codes are low voltage or comms errors.
A voltage test on a battery pretty much useless unless it's completely shot.

[SnikPlosskin]

Yes, the first thing is to look up every code. I’m not doing it. Too lazy.

[ZipZap]

Originally Posted by SnikPlosskin

Yes, the first thing is to look up every code. I’m not doing it. Too lazy.

Not starting makes those codes specious to me.

Can you clear codes on that car? If so, I would clear codes, start with jumpers and then check codes again. If the car doesn't start at all, I wouldn't trust the codes as low voltage can cause havoc in electronics.

An auto store should have a multimeter to borrow. I'd look at battery voltages as you try and start the engine to see how far they sag. Any reasonable "box store" repair shop should have a load tester for your battery as well.

If battery checks out well, and you can start it via jumper, the only easy thing to check is the connections at the battery, and the voltage at the starter. Everything else is probably managed by the electronics.

[09CTSV]

Lost Communication Faults

The digital data bus is damaged.
The main causes common to all the malfunctions described in this section are:
- disconnection of contacts due to vibration;
- corrosion or clogging, moisture entering the connector;
- melting of contact elements on the block as a result of voltage drops;
- damage to the cable, an open circuit connected to the device;
- wear of the insulating layer on the line, which led to a short circuit in the wiring;
- equipment failure.

[MadInNc]

Originally Posted by 09CTSV

Lost Communication Faults

The digital data bus is damaged.
The main causes common to all the malfunctions described in this section are:
- disconnection of contacts due to vibration;
- corrosion or clogging, moisture entering the connector;
- melting of contact elements on the block as a result of voltage drops;
- damage to the cable, an open circuit connected to the device;
- wear of the insulating layer on the line, which led to a short circuit in the wiring;
- equipment failure.

That’s going to hurt

[carlton_fritz]

Originally Posted by 09CTSV

Lost Communication Faults

The digital data bus is damaged.
The main causes common to all the malfunctions described in this section are:
- disconnection of contacts due to vibration;
- corrosion or clogging, moisture entering the connector;
- melting of contact elements on the block as a result of voltage drops;
- damage to the cable, an open circuit connected to the device;
- wear of the insulating layer on the line, which led to a short circuit in the wiring;
- equipment failure.

I have heard it might be a relay. The problem is that all the YT videos are for previous gen cars. Or I don"t know how to search...

[Rodnok1]

Step one keep it simple... Check connections at battery and check battery, if you dont do that first wasting your time as any corrosion or non tight connection reaks havoc with never vehicles. We're talking if you turn the connections 1/8 to 1/4 they were loose or frankly any turning at all.
Next up i always check the grounds, visual check usually good enough.
If you just start randomly checking and replacing stuff you'll end up insane like the rest of us.
If voltage in battery is weak /bad connection or ground and you jump start them you can easily damage computers especially if using high amp starter.
I've known several people who's battery went completely dead and someone jumped them and ruined computers, they can't handle voltage spikes and swings.
Good luck.

[Rikki Z-06]

Originally Posted by Rodnok1

Step one keep it simple... Check connections at battery and check battery, if you dont do that first wasting your time as any corrosion or non tight connection reaks havoc with never vehicles. We're talking if you turn the connections 1/8 to 1/4 they were loose or frankly any turning at all.
Next up i always check the grounds, visual check usually good enough.
If you just start randomly checking and replacing stuff you'll end up insane like the rest of us.
If voltage in battery is weak /bad connection or ground and you jump start them you can easily damage computers especially if using high amp starter.
I've known several people who's battery went completely dead and someone jumped them and ruined computers, they can't handle voltage spikes and swings.
Good luck.

[Rodnok1]

Originally Posted by Rikki Z-06

My son fried an ICM and pretty sure the HVAC controller doing high amp starter booster.
I almost killed him on the spot. Luckily the ECU wasn't damaged or he would died.

[John Wiz]

If your going to do much work on that car, I highly recommend the VCDS cable. We've had up to 4 audi's here, they've been great cars - but you really need a diagnostic cable.

You said it was a new battery, was it an Audi battery? It seems the VW/Audi products are extremely sensitive to voltage and will not do anything if it is under voltage. Also, in looking at the VCDS page, it could be that or a relay issue.

https://www.google.com/url?client=in...dQgfPDPpNa79oj

Not sure where you are located, but I'd offer you my cable if you were nearby...

[carlton_fritz]

Originally Posted by John Wiz

If your going to do much work on that car, I highly recommend the VCDS cable. We've had up to 4 audi's here, they've been great cars - but you really need a diagnostic cable.

You said it was a new battery, was it an Audi battery? It seems the VW/Audi products are extremely sensitive to voltage and will not do anything if it is under voltage. Also, in looking at the VCDS page, it could be that or a relay issue.

https://www.google.com/url?client=in...dQgfPDPpNa79oj

Not sure where you are located, but I'd offer you my cable if you were nearby...

Located in Indiana. I have an OBDEleven that is made for Audi. It showed battery at 14.0 volts. I am thinking I need to find the ECU and relays. WAs not where a YT video claimed, or I just did not know what I was doing.

[carlton_fritz]

Originally Posted by John Wiz

If your going to do much work on that car, I highly recommend the VCDS cable. We've had up to 4 audi's here, they've been great cars - but you really need a diagnostic cable.

You said it was a new battery, was it an Audi battery? It seems the VW/Audi products are extremely sensitive to voltage and will not do anything if it is under voltage. Also, in looking at the VCDS page, it could be that or a relay issue.

https://www.google.com/url?client=in...dQgfPDPpNa79oj

Not sure where you are located, but I'd offer you my cable if you were nearby...

Based on more research, I am suspecting a relay. Not being familiar with relays, will one that is the same part number, but listed for fog lamps or something else, work to replace a relay for the ECU?

[Anjdog2003]

Never own a German car after the warranty is up.



YW

[carlton_fritz]

Found this.


https://static.nhtsa.gov/odi/tsbs/20...55713-5611.pdf

[GTOguy]

Originally Posted by Anjdog2003

Never own a German car after the warranty is up.



YW

As an automotive professional for over 40 years, this is 100% correct. Audi is the least reliable of all the German cars, and have been known for electrical gremlins for decades. Only British cars have more electrical issues.