thespaugh

Hey guys - I have a 2012 A6 with the 3.0 and I've had intermittent starting the 4-5 mornings of the last week. Push button start cranks and cranks but the car doesn't start. if I leave it an come back 2-3 minutes later it fires right up.

Via VCDS I'm getting the following fault codes:

6455 - ECM Power Relay Control Circuit
P0687 00 [037] - Short to Plus


6450 - System Voltage
P0562 00 [032] - Too Low

I had the battery load tested and it passed, I'm now thinking perhaps is the ECM relay.

Does this sound plausible?

Also, I can't find where the ECM or it's relays are...can some one help me?

Thx

Fithian

I think there is a recall on that. Check with the dealer.

tenspeed

With the "6450 - System Voltage P0562 00 [032] - Too Low" fault code, I would suspect the original battery is on it's way out. Put the car on a charger or battery tender to see if you have the fault with a fully charged battery.

The ECU and some relays are located in the engine compartment. They are on the drivers side rear on the fire wall under the washer fluid bottle.

I have may ECU being held with a bungee cord in this picture.

thespaugh

Thanks for the replies. I had my battery load tested and it passed. I pulled the ECM relay today (Part# 4H0951253A), shook it a little, cleaned the connections and reinstalled. The car started right up. Not sure if this relay is the issue but now that I have a part number I ordered a new one.

Stoliguy

I've been searching for this forever. You're exactly right. The relay sticks open.
giving the relay box (by the washer fluid) a smack resets it and you'll hear a click from near the back of the supercharger.
If it fires up, you need a relay!

BOPOH

good old way to fix electronics - smack it

thespaugh

Yep, new relay it was. After installing the new one, I've not had a single problem since.

mosesdman

Having the same problem (2012 prestige as well), ordered a new relay, 4H0951253A. I cant seem to find out which relay is the "ECM relay "and even if there is a relay for the ECM, since the Audi parts list has the part number as (AC relay. Horn relay. RELAY. Relay assy. WINDOW RELAY. This Fits Your 2012 Audi A6 Prestige Quattro 3.0L V6 A/T AWD). Also noticed that there is a fuel pump relay as well SO can anyone direct me to the relay that needs changing?

rickateri

I recently had an events that scared the crap out of me with my 2012 A6 quattro. I was driving at hwy speed 65 mph and suddenly the parking brake came on along with the TPS sensor and steering malfunction indicater lights. Thankfully I could pull to the shoulder of the road safely . I turned off the car and checked around the exterior for a flat tire or anything but could not find any problem. Once I calmed down i started the car up and all the warning lights disappeared and I could drive again. The next day I made time to drive to my local Audi dealer and on the way the car died and would not start. All the warning lights again appeared but could start. I called AA and had the car towed to the dealer. After several days now they discovered there was a faulty wire at the comfort control module. We got it fixed and the car seems to be fine. I'm writing a letter to Audi USA headquarters in hopes this doesn't happen to anyone else while driving at hwy speed. Things could have turned out really bad. ( post Dec, 2018)

Aloalo x

Hej long time u posted but could you specify what exactly was wrong cause i might have the same issue