Bad charger contact cause Check Engine Light

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AvH

Member
Joined
Aug 5, 2019
Messages
14
This serves as a public service message - and it may save a lot of money, as the Check Engine Light is NOT a problem in the car, but due to a contact issue of the charger.

My etron was getting Check Engine Light (CEL) to come on after charging (at 120V) at home, but it never came on after charging at work. Home charging also didn't always work or only partly charged.

I can read out the OBD2 codes with a Bluetooth reader module and iPhone app - and also reset the CEL to go off. The error code is pasted below.

Long story short: I cleaned all contacts of the J1772 plug and socket and also the 120V plug - that one actually showed some black dirt/corrosion on the pins, esp the grounding pin (due to outdoor use I guess). After a thorough cleaning of the contacts, the CEL has not come on anymore, and charging works as expected.

I guess most people would bring the car to the dealer if the Check Engine Light comes on. The dealer can (and probably likes to) replace tons of stuff, but the problem is not in the car - even while the ODB2 information shows below error for all 8 battery cells.

By the way: the full OBD2 data shows a lot of errors, you must take the delta between good and bad to know what is relevant.

26719
Raw code: 00685F
ECU: 8C. Hybrid battery management (UDS)
Status: Test failed (current drive cycle), Pending, Confirmed, Test failed since last DTC clear, Warning indicator requested
Audi: P0D5600: Proximity Detection Circuit
 
Thank you for this. I think you’ve just saved me $3000… can I ask how you cleaned the contacts?
 
Nice to hear!

I used a small steel brush to clean the protruding contacts on the plug.

I don't know if corrosion was present in the J1772 connector (those contacts are holes), but I cleaned the three big ones with a cleaning brush (they are sold to clean metal reusable drinking straws) and the two small holes with a bent-open paperclip.

I was out of electrical contact spray, but that often can prevent or fix contact issues also. Keeping the contacts from water/rain always is prudent - if possible. I guess this is also why Audi added this somewhat awkward rubber cap over the car-side J1772 socket.
 
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