Recalls & faults: Audi C6 A6 (2004-11)

Recalls: Audi C6 A6

Overview

Manufacturers, or importers, issue recalls for defects or faults which have the potential to cause injury. Generally, manufacturers will inform the original buyers if their vehicle is subject to a recall and of the steps required to remedy the defect or fault. Please note that the recalls below (if any) are for Australian-delivered vehicles only. Furthermore, the number of recalls should not be taken as an indication of a model’s reliability or its safety more generally.

Recalls: Audi C6 A6

Audi C6 A6: airbag programming

In June 2007, a recall was issued for Audi C6 A6 vehicles due to inappropriate software programming of the airbag deployment trigger sensor in some vehicles – at worst, this may delay the deployment of the front airbags in the event of an accident (PRA 2007/9313).

Audi C6 A6: tailgate may close unexpectedly

In October 2007, a recall was issued for Audi C6 A6 Avant models due to a condition in which the power-operated tailgate may close unexpectedly and abruptly, shortly after being opened using the power function – this posed a risk of injury to persons when loading or unloading the vehicle and could be remedied by a software update (PRA 2007/9542).

2009-11 Audi C6 A6 2.0 TDI: NOx emissions defeat device

In October 2015, Audi Australia issued a recall for Audi C6 A6 vehicles with 2.0-litre EA189 diesel engines that were available for sale from 2009 to 2011. According to the recall notice, the exhaust emissions for these vehicles ‘may not meet regulatory requirements when the affected vehicle is driven under normal conditions’ (see ‘Diesel engines: NOx emissions “defeat device”‘, below). For the 2.0-litre EA189 engine, a software update will be introduced which takes advantage of improved simulation of air currents inside the air intake system. Volkswagen aims to implement the software update from January 2016; the labour time for installing the updated software is around half an hour. Owners could determine whether their vehicle was included in the recall by using a VIN checking tool at audi.com.au (PRA 2015/14956).

2011 Audi C6 A6 2.0 TFSI: coolant pump may catch fire

In May 2017, a recall was issued for Audi C6 A6 vehicles that had 2.0-litre turbocharged petrol engines (Audi’s ‘2.0 TFSI’) and were manufactured in 2011. In these vehicles, foreign particles in the coolant could cause a blockage in the additional coolant pump and cause the pump to overheat. In isolated cases, the overheated coolant pump could catch fire if it were not repaired. For the VINs of the recalled vehicles, please see PRA 2017/16068.

Audi C6 A6: Takata airbag recall

In December 2018, recall campaign 69R7 was issued for Audi C6 A6 vehicles. These vehicles had Takata front passenger airbags and the propellant wafers in these airbags could absorb moisture over time. In the event of airbag deployment, excessive internal pressure could cause the metal inflator housing to rupture and metallic fragments could be projected through the airbag cushion towards vehicle occupants – these fragments posed a risk of serious injury and fatality. For the VINs of the recalled vehicles, please see PRA 2018/17210.

Problems and faults: Audi C6 A6

Overview

This section identifies potential problems, causes and fixes based on the experiences of owners and repairers, online sources and technical service bulletins. This information is provided solely for reference purposes and AustralianCar.Reviews recommends that only properly qualified persons carry out repairs or modifications. Furthermore, the number of items below should not be taken as an indicator of a model’s reliability or the frequency with which they may occur.

To report a problem or fault to the AustralianCar.Reviews team, please use the Contact Us form. Note that AustralianCar.Reviews does not offer advice on automotive problems or disputes; such enquiries will not receive a reply. For vehicles purchased from dealers after 1 January 2011, please see our Australian Consumer Law fact sheet.

Audi A6 V6 diesel engine: NOx emissions “defeat device”

Audi C6 A6 vehicles powered by 3.0-litre diesel V6 engines (engine code: CDY) that were available for sale from 2008 to 2011 have software in the electronic control module (ECM) that can sense – via sensors measuring the position of the steering wheel, vehicle speed, the duration of the engine’s operation and barometric pressure – when the vehicle is undergoing emissions testing. The ECM then operates in a low NOx “temperature conditioning” mode to satisfy emissions standards.

At exactly one second after the completion of the initial phases of the standard test procedure, the software immediately switches to a “normal mode” and changes a number of operating parameters that increased NOx emissions. In other tests where the vehicle did not experience driving conditions similar to the start of the emissions testing procedure, the emissions were higher from the start, consistent with the operation and existence of a “normal mode”.

The software on these vehicles constitutes a “defeat device” since it is an Auxiliary Emissions Control Device (AECD) designed to circumvent emissions testing. Volkswagen has admitted that all its 3.0-litre turbo-diesel engines from ‘model years’ 2009 through to 2016 have defeat devices.

Audi A6 I4 diesel engine: NOx emissions “defeat device”

Australian-delivered Audi C6 A6 vehicles powered by 2.0-litre diesel engines that were available for sale from 2009 to 2011 had software in the electronic control module (ECM) that could sense – via sensors measuring the position of the steering wheel, vehicle speed, the duration of the engine’s operation and barometric pressure – when the vehicle was undergoing emissions testing. The ECM would then run a ‘dyno calibration’ to produce lower nitrous oxide emissions during testing. At all other times, the ECM would run a separate ‘road calibration’ which reduced the effectiveness of the emission control system, specifically the selective catalytic reduction (SCR) or the lean NOx trap.

Based on testing conducted by the EPA and the California Air Resources Board (CARB), NOx emissions for the ‘road calibration’ were 10 to 40 times higher than US standards – this led the United States Environmental Protection Agency (EPA) to issue a notice of violation under the Clean Air Act. As a result, these vehicles did not meet the environmental standards claimed by Audi.

Carbon deposits (build-up) on intake valves

Audi’s naturally aspirated, direct injected petrol engines (such as the C6 A6’s 2.8 FSI, 3.2 FSI and 4.2 FSI) are considered susceptible to accumulating carbon deposits (or build up) on the intake valves. In these direct injection petrol engines, carbon deposits may accumulate on the stem and throat of the intake valve due to:

1. the vaporisation of oil which is not trapped by the oil separator; or
2. unburned fuel and exhaust gases that escape past the piston rings and enter the crankcase (‘blow-by’).

Since direct injection engines do not spray fuel on the backside of the intake valves, the detergent properties of the fuel cannot remove the carbon build up (as occurs in port injected engines). Symptoms of carbon deposits on the intake valve include difficulty starting the vehicle (hard starting), misfiring and misfire engine codes and reduced engine performance. Potentially, these deposits can result in damage to the catalytic converter and, for turbocharged engines, the turbocharger itself if bits of the deposit break off and enter the exhaust. To remove the carbon deposits, the intake must be removed and the valves cleaned manually. To reduce the incidence of carbon deposits, a common aftermarket measure is the fitment of an oil vapor catch can. The catch can receives dirty air from the crankcase via the Positive Crankcase Ventilation (PCV) valve, filters it and returns it to the intake manifold via the PCV port.

Audi C6 A6 3.2 FSI: rough idle and hesitation

In November 2008, Audi issued technical service bulletin 2010890/8 for 2005-06 Audi C6 A6 3.2 V6 FSI vehicles. In these vehicles, the driver may experience:

• A rough idle after a cold start;
• The engine may stumble or hesitate at slow initial acceleration after a cold start and under certain weather conditions; and,
• The engine may attempt to stall at idle when the transmission is shifted from Neutral or Park to Drive or Reverse when coolant temperature is above 80 degrees Celsius and the vehicle is stationary.

To fix, the Engine Control Module (ECM) was to be reprogrammed with new software.

Audi C6 A6 3.2 V6 FSI & 4.2 V8 FSI: low-pressure fuel system sensor

In March 2008, Audi issued technical service bulletin 2015106/4 for 2005-08 Audi C6 A6 3.2 V6 FSI and 4.2 V8 FSI vehicles. In these vehicles, the Malfunction Indicator Lamp (MIL) may illuminate and the following diagnostic trouble codes (DTCs) may be logged –

• P310B: low-pressure fuel system regulation, fuel pressure outside tolerance; and,
• P129F: low-pressure fuel system, pressure too high.

According to the service bulletin, this condition may be caused by fuel intrusion into the low-pressure system fuel pressure sensor (G410), such that a false signal that was out of tolerance was sent to the controller. Subsequently, improvements were made to the G410 fuel pressure sensor.

Engines

• After sitting overnight, the 2.0- and 3.2-litre petrol engine may run rough, misfire and activate the ‘check engine’ light because the hydraulic valve lash adjusters drain down and must be replaced.
• For models with the 3.2-litre V6 petrol engine, the camshaft sealing plugs in the cylinder heads may come loose and cause an oil leak. To fix, the old plugs need to be removed and re-designed plugs installed. Oil leaks may also occur at the timing chain upper covers, requiring fresh sealant.

Audi C6 A6 Multitronic (CVT): no drive or delayed drive

In January 2007, Audi issued technical service bulletin 2013280/1 for Audi C6 A6 vehicles with 01J continuously variable transmissions (CVTs, or Audi’s ‘Multitronic’) that were manufactured from May 2005 to May 2006. In these vehicles, the following conditions occur:

• No drive or delayed drive when ‘D’ or ‘R’ is selected. Furthermore, Diagnostic Trouble Code (DTC) P1743/18151 may be logged in the Transmission Control Module (TCM) fault memory; and/or,
• When accelerating from ret, an increased engine speed is necessary to move the vehicle.

According to the service bulletin, some seals for the CVT may have been damaged in production and leak after a short operating period (less than 20,000 kilometres), causing a loss of transmission oil pressure.

Audi C6 A6 Multitronic: emergency running mode and DTCs

In May 2007, Audi issued technical service bulletin 2012154/8 for 2006-07 Audi C6 A6 vehicles with 01J continuously variable transmissions (CVTs, Audi’s ‘Multitronic’). In these vehicles,

• The Malfunction Indicator Light (MIL) may illuminate;
• The vehicle may enter emergency running mode with gear indicator illumination inverted; and,
• Diagnostic Trouble Codes 17090-P0706 (transmission range sensor circuit range/performance) or 18201-P1793 (output speed sensor 2 circuit no signal) may be issued.

If either of the above Diagnostic Trouble Codes (DTCs) were logged, the Transmission Control Module was to be replaced.

Audi C6 A6 quattro: noise when shifting to/from fourth gear

In December 2006, Audi issued technical service bulletin 2013023/1 for 2005-06 Audi C6 A6 quattro vehicles because a chirping, hooting or squeaking noise may be heard when shifting to and from fourth gear. Furthermore, shudder may be experienced during the control phase of the torque converter clutch.

According to the service bulletin, the torque converter clutch briefly generated vibrations/shuddering during the control phase of the converter control/converter close. To fix,

• The transmission control unit was to be reprogrammed;
• The automatic transmission fluid was to be drained, filled, flushed and re-filled with ATF specification ‘G 055162A2’ (blue); and,
• An adaptation drive performed.

Audi C6 A6: air conditioning doesn’t work

In April 2010, Audi issued technical service bulletin 2020124/2 for Audi C6 A6 vehicles because the air conditioning (A/C) may stop working. According to the service bulletin, this may be caused by the A/C pressure/temperature sensor G395 leaking refrigerant – this would cause sensor G395 to show an incorrect or implausible value when reading MVBs (Measuring Value Blocks) such that the air conditioning compressor would deactivate; or,

An improved A/C pressure/temperature sensor G395 was introduced in series production (part no. 4F0 959 126C).

Audi C6 A6 quattro: whining noise on deceleration

In June 2008, Audi issued technical service bulletin 2017932/1 for 2005-07 Audi C6 A6 quattro vehicles because a whining noise may be heard in deceleration from freeway speeds. According to the service bulletin, the whining noise was due to wear of the bearing and bearing carrier in the rear differential housing. To fix, the 01R final drive (which had a black housing) was to be replaced by the new 0AR final drive (unpainted and therefore silver in colour).

The 0AR final drive was introduced during MY 06-07 production for individual engine-gearbox variants.

Audi C6 A6 4.2 V8: misfires and ignition coils

In December 2006, Audi issued technical service bulletin 2013623/1 for 2005-06 Audi C6 A6 vehicles with 4.2 V8 engines and VINs in the range 4F 5N 049500 to 4F 6N 184000. In these vehicles,

• The Malfunction Indicator Light (MIL) may be flashing or constantly illuminated; and,
• Diagnostic Trouble Codes (DTCs) for misfire in one or more cylinders (P0300 to P0312, depending on the engine) are stored in the Engine Control Module (ECM).

According to the service bulletin, the misfire could be caused by the ingress of moisture in the ignition coils. Furthermore, new ignition coils supplied by Powertrain Pulse ERA were installed in production.

Problems and faults: Audi C6 A6

• The anti-lock braking system (ABS) may activate unnecessarily under normal to light braking pressure due to cracks in tone/exciter rings (rings on the outer CV shaft that measure wheel rotation).
• The coolant level warning light may illuminate in cold temperatures and then go off as the engine warms up – this may be due to a malfunctioning sensor in coolant reservoir.
• It may not be possible to remove the key from the ignition because the transmission selector fails to recognise that the transmission is in park – this requires replacement of the transmission shift selector.
• The remote central locking may sometimes not unlock the doors due to a problem with the door modules – this can be fixed by reprogramming the door modules.
• If the fuel gauge does not provide a full reading after re-fueling, the program for the instrument cluster may need to be updated.
• For some early models, the fuel door may not open because the release cable caused interference – the cable must be re-routed.The master power window switch may work intermittently due to interference with the trim.