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Audi S3 1.8t common faults

IFFY_77 Dec 1, 2012

  1. IFFY_77

    IFFY_77 Member

    Found this online iv had quite a few of the common faults mentioned thought it would b helpful to others especially if your buying a S3.
    Or you can see how many you have had ... Lol

    Audi S3 1.8T common faults/ buying check list

    Hopefully it may be of use to have a list of common S3 faults in one place. Based on experience on my car that I’ve owned for 6 years and/or research through these forums. I've noticed a large number of these faults in the last couple of months hence I decided to write a list, feel free to add to it. Apologies for any inaccuracies in advance. Shocking how many common faults there are for an Audi…

    My car is an Audi s3 1999 8L, APY engine (pre facelift) 87k, 11 years old

    Common Fault
    Solution Age Mileage

    Window Clips
    Plastic clips that run up and down on regulator are prone to fatigue causing window to malfunction and not close.
    Replace with A6 metal clips 5 34k

    Plastic impeller prone to failure causing overheating and damage to thermostat
    Replaced with metal pump, replace thermostat if overheating occurs 7.5 59k

    Concert Stereo volume
    EPROM memory is ‘write only’ memory which fills up every time volume is changed. When EPROM is full, every time volume is adjusted it will go silent or full volume
    Repaired by OE Electronics, Salisbury 7.7 62k

    Backup battery in Alarm Siren
    Siren battery stops holding charge which leads to car alarm going off. A sign is 3 beeps from the rear passenger side before siren continually sounds.
    Remove or replace alarm siren. Some have repaired this unit. 7.7 62k

    Heat shield for cat
    Bolts holding heat shield rust and break off causing a rattling exhaust noise
    Replace bolts 7.7 62k

    Front ARBs
    Plastic collars break off. These collars butt up to the mounting bush. Part from Audi has been updated.
    Replace entire ARB 8.7 73k

    Track rods ends and wishbone bushes
    Prone to wear out.
    Wishbone bushes crack.
    Replace part 8.7 73k

    Roof rail corrosion
    Sealant along weld line joining roof to quarter panel breaks down and allows water in and hence corrosion
    Respray both sides covered by warranty if less than 12 years old and not neglected 9.7 80k

    Brake Vacuum Hose
    Vacuum pipe connecting brake servo to inlet manifold uses a hard plastic which cracks at joints from heat cycling
    Replace part 10.7 86k

    Rear springs
    Rear springs corrode and then snap at the base
    Replace part 10.7 86k

    Diverter Valve
    Lumpy cold running and low boost problems. Test by removing, pushing diaphragm up then placing finger over vacuum tube on top. Diaphragm should stay put else needs replacing
    Replace with OEM P/N ending 710N 10.7 86k

    Brake light switch on pedal
    Prone to fail overtime. Throws a fault intermittent fault code and eventually brake lights stop working. Less common on facelift models
    Replace part 10.7 86k

    DIS dead pixels
    DIS pixels fail overtime 5 34k

    Glovebox lid hinges
    Hinges snap over time
    Replace glovebox lid. 9.7 80k

    Rough running at idle, running rich, running lean, cold start problems, poor mpg
    Test 1 - Disconnect MAF and default MAF values will be used. Engine will run better if MAF is faulty.
    Test 2 - Log Block 002 using VAG COM. MAF values should be 0.8xengine BHP.
    Reset ECU with MAF changes
    Clean with electrical cleaner or replace MAF. Reset ECU. 10.8 87k

    Rear wash wipe
    Pump running but water not coming out of rear wash wipe
    Check jet is not blocked and then check pipe joins through the car by running pump and looking for leaks. Joint under the bonnet LH side tends to be first to come apart. 4 26k
    Common Faults not yet had:

    Xenons pointing towards ground
    Sensors on nearside suspension front or rear can fail, or motors within headlight. If it’s the motor normally only one light is affected
    Replace sensor or headlight motor

    Rust along lower door trims
    Door panels rust behind lower trim
    Some have claimed on warranty

    Clutch pedal switch
    Causes car to over rev when the clutch pedal is depressed
    Replace switch

    Clutch pedal
    Plastic part of pedal prone to failure

    Coil Packs
    Early models used Hitachi coil packs and few failures. Hitachi packs replaced by bosch part which is prone to failure
    Replace part

    Venturi vacuum pump
    Can clog up with oil from the oil breather (this might only be on A3)
    Can be cleaned or replaced

    Breather / vacuum pipes
    Prone to failure overtime from heat cycling
    Replace affected pipe

    Clutch/ clutch slave cylinder & flywheel
    Clutch slave cylinders can fail, leaking fluid over clutch.
    Both slave cylinder and clutch require replacing if slave cylinder fails. If clutch goes maybe worth replacing slave cylinder at same time

    Can fail with age or if waterpump impellers fail and engine overheats. Plastic impellers can travel round engine and get caught in thermostat preventing to open and close correctly. Temp gauge no longer sits bang on 90 deg. Coasting downhill tends to drop below 90.
    Replace part. Ensure battery is disconnected as thermostat is directly behind live connection on alternator

    Coolant Temperature Sensor
    Early models used a black sensor which are prone to failure. Uprated part is green. Causes poor running. Temp gauge become erratic, check values on block 011.
    Replace part. Open then close header tank to release pressure before changing.

    Door sensor microswitches
    Switches cause DIS to indicate door still open after it has been closed
    Microswitches need realigning

    Front Sus Top Mounts
    Top mounts wear out causing knocking noise
    Remove suspension, Replace part

    Oil dipstick
    Plastic outer of oil dipstick becomes brittle and cracks. Sometimes broken parts can fall into engine.
    Replace part

    Ignition Barrel
    Fail overtime

    Oil sump pick up pipe
    Pickup pipes can become blocked with grit like material. Thought to be worse on BAM engines or engines running longlife servicing.
    Drain oil, remove sump, clean oil breather pipe or replace (£12), reinstall using audi sump sealant. 3 bolts particularly difficult to reach

    Rear ARBs
    Same problem as front although less common, collars within bushes snap at the ends and entire ARB has to be replaced. Some have found ARB needs replacing after rear springs have been renewed
    Replace entire ARB

    Coolant Level Sensor
    Sensors can fail overtime and indicates low coolant on DIS. Cabling to the switch can come loose from plug
    Clean sensor or replace. Replacement involves whole new header tank

    Fuel Pump Relay
    The fuel pump relay is located under the driver’s side kick panel. Remove the lower panels to gain access to the relay box. When the fuel pump relay goes remove the lower panels to gain access to the relay box. When the fuel pump relay goes bad it will trigger many fault codes with electrical shorts to ground. The fuel pump relay is also used to turn on the injectors, and will show injector short to ground failures. If you open your door you hear the pump kick on, if the pump no longer kicks on, and you experience these codes repeatedly, replace the fuel pump relay.
    JudderMan likes this.
  2. s33nyboy12

    s33nyboy12 Well-Known Member Team Ibis Team V8 Audi R8 s tronic

    Which ones of these didn't go on my s3!!!!! Also when i looked through the service history at previous bills 2 clutches .... Nice driving from the one careful previous owner !

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