AUDI EPC LIGHT

AUDI HAS LOOMINITUS

Audi TT, A4 1.8T, A4 B5 1.8 Auto, 2.5 V6 Quattro B6, 1.6L A4 SE, 1.8L R4, Audi 8T0, Audi A6 C5,

Does your Audi occasionally have a hard time starting, yet finally starts just before you give up?  So when it starts, the EPC and ESP lights are on, then the engine cuts out. You restart and she idles rough and the check engine light comes on? After a while the EPC and ESP light go out, thereafter the car drives normal until the next time this happens. 

Or, as you are driving in manual mode, you noticed the ABS and ESP lights come on and suddenly your Audi's engine loses  power and goes into limp mode. You switch off, then restart, it idles rough but won't rev over 1500 RPM and she sounds like a tractor. You switch off once again, restart and the tractor is gone. So you get the Audi home driving at a snails pace, the next morning you start her and it seems like there was never any problems because she now idles and drives normally.

Or you are VCDS savvy, encountered an EPC light problem, cleared the fault and the next day it come back on. Several days later the EPC light comes on again, stays on and refuses to switch off. Once again you do a scan and you get a ton of  implausible  and intermittent DTC errors. 

Or your start the Audi, it idles for a few seconds then dies with the EPC light and ESP lights on. You clear the faults, lights go out. You drive the car for less than 3 km and it goes into limp mode. You disconnect the battery and reconnect and it seems fine thereafter. A few days later and the same thing occurs.

The Throttle body plug thats seem to haunt Audi owners.

What you have been experiencing is just a sampling of what the future holds. You Audi is suffering from "loominitus",  its loom is having issues, better known to auto electricians and motor mechanics as wiring harness issues. The culprit in all the above case is the 6 pin plug interfacing with the throttle body. Of late, this throttle body plug has become  quite trouble, you could almost call it common. Don't use contact spray on the plug. Ideally that portion of the loom needs to be replaced but since the female part of the plug is intermittent - hence faults come and go - it's worthwhile just replacing the plug and join the wires using ferrules and double crimp them. Cover the wires with shrink sleeving and avoid insulation tape because the engine heat will melt the PVC which will go sticky within days and  its messy.  

The troublesome Throttle body plug - connect thicker wires as per old plug.
Pin 1-blue/white stripe, Pin  2-purple/white stripe, Pin  3-white, Pin  4-blue/grey stripe, Pin  5-purple/black stripe, Pin  6-white/grey stripe

Throttle body replacement plug and colour coded wiring

I am so sorry to say, as the looms in the newer cars age, you should expect worse issues with the wiring harnesses.  See the list of sub loom components for the VW Polo here. Pieces of the harness that makes-up the whole.

Anyway should you scan your ECU, you will most probably find the following faults and perhaps others not listed here. The image below points to the troublesome plug.

18010 - Power Supply Terminal 30: Voltage too Low
P1602 - 35-10 - - - Intermittent
01314 - Engine Control Module
013 - Check DTC Memory - Intermittent
18084 - EPC Warning Lamp (K132) Circuit
P1676 - 35-00 - Electrical Malfunction
01176 - Key
65-10 - Unauthorized - Intermittent
01177 - Engine Control Unit
64-10 - Not Currently Testable - Intermittent
01119 - Gear Recognition Signal
             35-10 - - - Intermittent
18264 - Throttle Potentiometer (G69): Error Message from ECU
             P1856 - 35-10 - - - Intermittent
00258 - Mass Air Flow Sensor (G70)
              P0102 - 002 - Signal too Low - Intermittent
18039 - Accelerator Position Sensor (G79)
P1631 - 35-00 - Signal too High
18042 - Accelerator Position Sensor 2 (G185)
P1634 - 35-00 - Signal too High
00768 - Random/Multiple Cylinder Misfire Detected
              P0300 - 35-00 - -
16685 - Cylinder 1: Misfire Detected
             P0301 - 35-00 - -
16688 - Cylinder 4: Misfire Detected
              P0304 - 35-00 - -
16690 - Cylinder 6: Misfire Detected
              P0306 - 35-00 - -
16689 - Cylinder 5: Misfire Detected
             P0305 - 35- 00 - -
17953 - Throttle Valve Controller
P1545 - 35-10 - Malfunction - Intermittent
17981 - Left Engine Mount Solenoid Valve (N144)
              P1573 - 009 - Open Circuit
00473 - Control Module for Elect. Park/Hand Brake (J540)
              008 - Implausible Signal - Intermittent
01494 - Bulb for Parking Lamps; Left (M1)
             011 - Open Circuit
01504 - Bulb for License-Plate Light (X)
              009 - Open or Short to Ground - Intermittent
02255 - Voltage Measuring Lead from Vbat
             009 - Open or Short to Ground
16706 - Engine Speed Sensor (G28): No Signal
             P0322 - 35-00 -  -
00285 - ABS Wheel Speed Sensor; Front Right (G45)
008 - Implausible Signal - Intermittent
00283 - ABS Wheel Speed Sensor; Front Left (G47)
012 - Electrical Fault in Circuit - Intermittent
18057 - Powertrain Data Bus: Missing Message from ABS Controller
P1649 - 35-10 - - - Intermittent
16795 - Secondary Air Injection System: Incorrect Flow Detected
P0411 - 35-10 - - - Intermittent
17511 - Oxygen (Lambda) Sensor Heating; B1 S1: Performance too Low
P1103 - 35-10 - - - Intermittent
16497 - Intake Air Temp. Sensor (G42): Signal too High
P0113 - 35-10 - - - Intermittent
16955 - Brake Switch (F): Implausible Signal
P0571 - 35-00 - -

Audi on a rollback, notice the open bonnet

Audi on a rollback, number plate scratched for privacy

Audi on a rollback just before  peak hour in the afternoon.

Audi on a rollback enroute the service centre.

Audi on a rollback  

Audi TT, A4 1.8T, A4 B5 1.8 Auto, 2.5 V6 Quattro B6, 1.6L A4 SE, 1.8L R4, audi 8T0, Audi A6 C5,

Feel free to upload your VW, SKODA, SEAT & AUDI scans.

WIRING HARNESS ISSUES

AUDI ON A ROLLBACK

As I've mentioned in my previous blog, not only Volkswagen  vehicles but every new vehicle's wiring harnesses have undergone a huge technological evolution since 1984. So much so that  30 years later the average wiring harnesses has become extremely complex because the number of terminals have progressively increased from a typical 200 terminals in a 1994 vehicle to as many as 1,400 terminals, if not more in the very latest models. It therefore stands to reason that with so many terminals or connections, each and everyone of them are subject to corrosion, high resistive contact, poor contact, intermittent and implausible contact  and at times no contact.  The amount of copper wire used in older cars have also decreased substantially, from as much as 4 kilometers in length to about 1 kilometer. That's equates to a 75% saving on the wiring harness.  However with all the new technology and control modules and data buses, the cost of the wiring harness  cost equates to a quarter of the cost of the entire car. 

VW Polo Wiring Harness

As can be see in the image below, another VAG car sucummbed to hi-technology and desperately needs the service centre because it went into "Limp Mode".  It's most likely an electrical fault has caused this but that's just speculation on my part. However, since more than 50% of all warranty repairs are caused by electrical malfunctions, and approximately 30 percent of all tow-ins, are due to problems associated with the wiring harness, it can be therefore be said that 80% of all troubles experienced by car owners today are due to electrical faults.  Can we then also say that these fault are constantly recurring  because the manufacturer has overlooked the fact that 1400 contacts will invariably be influenced by  bumpy roads, shaking and hoping and flexing, subject to moisture and heat and dust and dirt? Desktop computers also have several hundred contacts but the difference between household computers and cars is that computers stay in a fixed place and doesn't get knocked about and shake on bumpy roads nor subjected to extreme heat and cold and moisture. Wouldnt it be fair to say that any car with electrical problems caused by the wiring harness should be repaired by the manufacturer under warranty and if not, these cars should be recalled. Anyway,  here is the Audi scan for your perusal.

Audi on a roll back with immobilizer issues

Chassis Type: 8E - Audi A4
Scan: 01 02 03 08 09 0F 11 15 16 17 18 36 37 45 46 55 56 57 65 67 69 75 76 77
-------------------------------------------------------------------------------

Address 01: Engine Labels:
Part No: 8E0 906 018 B
Component: 1.8L R4/5VT 0004
Coding: 11701
Shop #: WSC 14385

7 Faults Found
17978 - Engine Start Blocked by Immobilizer
P1570 - 35-10 - - Intermittent
17698 - Coolant Temp Sensor at Radiator Outlet (G83)
P1290 - 35-10 - Signal too Small - Intermittent
00527 - Intake Manifold Temperature Sensor (G72)
30-10 - Open or Short to Plus - Intermittent
17536 - Fuel Trim; Bank 1 (Mult)
P1128 - 35-00 - System too Lean
18058 - Powertrain Data Bus
P1650 - 35-10 - Missing Message from Instrument Cluster - Intermittent
18043 - Powertrain Data Bus
P1635 - 35-10 - Missing Message from A/C Controller - Intermittent
16712 - Knock Sensor 1 (G61)
P0328 - 35-10 - Signal too High - Intermittent
Readiness: N/A


Address 03: ----------------------------------------------------------------------
ABS Brakes
Part No: 8E0 614 517 A
Component: ABS/ESP allrad 1326
Coding: 04275
Shop #: WSC 60690

1 Fault Found
01317 - Control Module in Instrument Cluster (J285)
49-10 - No Communications - Intermittent


Address 08: ----------------------------------------------------------------------
Auto HVAC

Part No: 8E0 820 043
Component: A4 Klimaautomat 0711
Coding: 00000
Shop #: WSC 24576

4 Faults Found
01317 - Control Module in Instrument Cluster (J285)
49-10 - No Communications - Intermittent
00716 - Air recirculation Flap Positioning Motor (V113)
41-00 - Blocked or No Voltage
00474 - Control Module for Immobilizer
49-00 - No Communications
00474 - Control Module for Immobilizer
27-10 - Implausible Signal - Intermittent


Address 09: ----------------------------------------------------------------------
Cent. Elect.
Part No: 8E0 907 279 A
Component: int. Lastmodul RDW 1010
Coding: 00011
Shop #: WSC 63351

4 Faults Found
01317 - Control Module in Instrument Cluster (J285)
49-10 - No Communications - Intermittent
00474 - Control Module for Immobilizer
49-00 - No Communications
01317 - Control Module in Instrument Cluster (J285)
79-10 - Please Check Fault Codes - Intermittent
01312 - Powertrain Data Bus
49-10 - No Communications - Intermittent


Address 15: ----------------------------------------------------------------------
Airbags
Part No: 8E0 959 655
Component: Airbag 8.4E 3001
Coding: 0011702
Shop #: WSC 63351 000 00000

No fault code found.


Address 16: ----------------------------------------------------------------------
Steering wheel

Part No: 8E0 953 549 F
Component: Lenks?lenmodul 0304
Coding: 00001
Shop #: WSC 63351


2 Faults Found
00474 - Control Module for Immobilizer
49-00 - No Communications
01317 - Control Module in Instrument Cluster (J285)
49-10 - No Communications - Intermittent


Address 17: ----------------------------------------------------------------------
Instruments
Part No: 8E0 920 900 HX
Component: KOMBI+WEGFAHRS. RB4 D27
Coding: 00142
Shop #: WSC 19411

2 Faults Found
01176 - Key
07-10 - Signal too Low - Intermittent
65535 - Internal Control Module Memory Error
00-00 - -


Address 45: ----------------------------------------------------------------------
Inter. Monitor

Part No: 8E0 951 177
Component: Innenraumueberw. 0504
Coding: 00001
Shop #: WSC 00000

No fault code found.

Audi on a rollback on the way to the clinic.

So by the looks of it, with so many error codes,  it does seem like the wiring harness could be faulty because the control module lost communications with the Instrument cluster and when this happened the checksum no longer tallied, so the immobilizer inhibited starting. But considering that the key signal was low or intermittent, it could even be that the CR1220 lithium battery in the key fob died hence could not deactivate the immobilizer. It's just so scary that your relatively new and supposedly reliable VAG vehicle could act up at any time on a lonely road and leave your stranded, so make sure you have a tow-inn agent on speed dial.


Feel free to upload your VW, SKODA, SEAT & AUDI scans.