I have had this problem for about 5 weeks now. It all started after I took my car in for an oil change but I'm sure that isn't what started it. When I start my car up in the morning to go to work it starts up just fine with no issues. After driving it for lets say 20 plus minutes or more if I turn off the engine it will not start. It doesn't try to turn over, it just goes straight to battery when I turn the key. I have to wait about 20 or more minutes until I can start the engine again. The check engine light is not on so there are no codes, should a have someone run it anyway to make sure there are no codes?

The only black and white thing I know is this. When I start my car the little red light that tells me to put my foot on the break lights up and I also get the message on the dashboard telling me to do some. When my car has heated up and will not start the little red light of the foot on break is not lit. I have sat in my car before on battery waiting and I noticed that the red light eventually lights up and the message on the dash displays to step on the break to select gears. After this I am about to start my car just fine. Any ideas on what could be causing this?

 

What year and what engine is that?

 

I'm wondering if this really isn't something to do with the park/ neutral safety switch... If it thinks its in gear it disables the starter. Your clue is the red light pressing the pedal.. Next time it won't start try wiggling the shift lever. If that doesn't work press foot down, pull it out of park, then slam it back into park. See if the car starts.

There is also something called Park Neutral Position (PNP) Relay J226?

Also known issues with something called a TCM - sometimes the wiring can get dirty or shorted to cause a no-start.

The Transmission Control Module (TCM) provides the ground from pin 4 Brown/White (BR/WS) when the shifter is in the Park and Neutral positions.

GOOD LUCK!

Steve

 

Here ya go!

Number: 536230
Vehicle Application:
2004 A6 Quattro 3.0
Customer Concern: Intermittent no start, no crank. There is no power at the starter.
Average Reported Mileage: 119020
Tests/Procedures: 1. Access the electrical portion of the ignition switch. With a Digital Volt Ohm Meter (DVOM), measure the voltage on terminal 50 Red/Black (RO/SW) with the key in the start position. Should read 12 V. If the voltage is not as specified, then replace the faulty ignition switch.

2. If the switch is good, then locate the starter interlock relay in the relay panel under the left side of the dashboard, position number 4 and remove the relay. Jumper terminals T9/2 Red/Black (RO/SW) and T9/8 Red/Black (RO/SW) and start the vehicle. If the intermittent starting problem does not recur, then test terminal T9/6 Brown/White (BR/WS) for a good ground. If a good ground is present, then replace faulty starter interlock relay. If a good ground is not present, then test the Multi-Function Transmission Range Switch as follows:

A. Pin 10/31 Brown (BR) should be a good ground at all times.

B. Pin 9/B Brown/White (BR/WS) should be a grounded in Park and Neutral only. If no ground signal is present, then replace the faulty Multifunction Switch.

3. If the vehicle will not start with the terminals jumped, then inspect the wiring between the relay panel and the ignition switch and the relay panel and the starter.
Author:
William Krug
Potential Causes
With Service Manuals diagrams, components, TSBs, and R&R procedures

Malfunctioning Ignition Switch

Failed Multifunction Transmission Range Switch (F125)

Starter Interlock Relay