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Let Car Idling For 7 Hours

Ton

Go Kart Newbie
Location
U.S.
I left my car idling for 7 hours. Once discovered I drove it around for 20 minutes and everything seemed okay. No codes and it responded normally. Today it cranks but won't start. Here's what I know.

#1 "P0657 Code: Actuator Supply Voltage A" is the only code.
#2 Gas tank is 1/2 full.
#3 Live data shows fuel pressure when cranking.
#4 Live data on crank sensor shows RPM when cranking so I assume it's working.
#5 Starting fluid in turbo inlet while cranking does not fire.

My next step is to tow it in the garage and check all fuses and see if I can get a closer look at anything that might be affected by heat. Then I'll start probing.

If anyone has any ideas or insights they would be greatly appreciated. Anything to look for in OBD11? Anything to test? Is the P0657 code is a clue and if so what does it point to?
 
Last edited:

scrllock

Autocross Champion
Location
MI
Mentioned this on your reddit post but #1 indicates a voltage issue. Idling won't necessarily keep your battery charged, especially in an extreme case like that.
I would try jumping it and if it starts, take it out for at least a 30 minute drive on the highway. Could be time for a new battery tho.
 

snobrdrdan

former GTI owner
I left my car idling for 7 hours.
 

hans611

Lost
Location
Miami
Car(s)
'16 Golf R 6MT
Was it in an open parking space or like in a closed garage? I don think think heat would be a problem if there was enough air to ventilate... the only electronical component that I know of that tends to be affected by heat in these cars is the ABS module, but that's bc its next to the downpipe and cat, it wouldn't be an issue on an idling car.

Like @scrllock noted, my money is on battery... such low rpm for so long was probably not enough to keep it charged.
 

Ton

Go Kart Newbie
Location
U.S.
Outside. About 45 degrees. It actually did smell pretty hot. It was giving off that plastic cooking oil smell.

I'm may be on to something. "645" relay in the engine compartment fuse box. It has a 1% tolerance 560ohm resitor. It measures about 60ohms. It's toast. I'll be checking other stuff and picking up the relay later today.
 

Ton

Go Kart Newbie
Location
U.S.
Was it in an open parking space or like in a closed garage? I don think think heat would be a problem if there was enough air to ventilate... the only electronical component that I know of that tends to be affected by heat in these cars is the ABS module, but that's bc its next to the downpipe and cat, it wouldn't be an issue on an idling car.

Like @scrllock noted, my money is on battery... such low rpm for so long was probably not enough to keep it charged.
How could it be the battery when the battery is fully charged, measures the correct voltage and the car cranks to the moon?
 

Ton

Go Kart Newbie
Location
U.S.
Well. It was fun. I hope everyone had a blast, I know I sure did. I vow to eliminate all tomfoolery from my life and get my shit together. No more extended idling.

For posterity and for anyone who has a similar problem, the solution:

2 underhood relays were toasted. Relay "644" and "645." The resistors inside are supposed to be 560 ohms. Mine measured unstable in the 50-70 range. I replaced the relays and the car runs. I put back the old relays and it doesn't. So I'm quite sure it is the relays. I was thinking of asking Scotty but he would just tell me VWs are endless money pits (as they age) and laugh at me.

Relays were 50 something each at the stealer. I could have found the them cheaper but I couldn't wait for delivery.

Thanks and good day.
 
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