2001 AUDI A4 & S4

Audi A4 2001 - BUZZERS, RELAYS & TIMERS

Audi A4 2001 BUZZERS, RELAYS & TIMERS LOCATION

Component	Component Location
A/C Clutch Relay	On 13-pin relay carrier, position No. 3. See Fig. 7 .
Coolant Fan Control (FC) Relay	On 8-pin relay carrier, position No. 3. See Fig. 6 .
Daytime Running Lights Switch-On Relay	On 13-pin relay carrier, position No. 8. See Fig. 7 .
Driving Light Relay	On 13-pin relay carrier, position No. 9. See Fig. 7 .
Dual Horn Relay	On micro central electric, position No. 1. See Fig. 5 .
Foglight Relay	On 13-pin relay carrier, position No. 7. See Fig. 7 .
Fuel Pump Relay	On micro central electric, position No. 4. See Fig. 5 .
Load Reduction Relay	On micro central electric, position No. 2. See Fig. 5 .
Motronic Engine Control Module (ECM) Power Supply Relay	On 3-pin relay carrier, position No. 3. See Fig. 4 .
Park/Neutral Position Relay	On 13-pin relay carrier, position No. 13. See Fig. 7 .
Power Window/Sun Roof Control Module Relay	On 8-pin relay carrier, position No. 4. See Fig. 6 .
Secondary Air Injection (AIR) Relay	On 3-pin relay carrier, position No. 2. See Fig. 4 .
Second Speed Coolant Fan Control (FC) Relay	On 8-pin relay carrier, position No. 2. See Fig. 6 .
Selector Lever Light Relay	On 13-pin relay carrier, position No. 6. See Fig. 7 .
Wiper/Washer Intermittent Relay (2)	On micro central electric, positions No. 5 & 6. See Fig. 5 .

Audi A4 2001 - CIRCUIT PROTECTION DEVICES

Audi A4 2001 CIRCUIT PROTECTION DEVICES LOCATION

Component	Component Location
Fuse Panel	On left end of dash. See Fig. 8 .
Micro Central Electric	Behind left side of dash. See Fig. 8 .
3-Pin Relay Carrier	Near brake booster, in ECM case.
8-Pin Relay Carrier	Below left end of dash. See Fig. 8 .
13-Pin Relay Carrier	Behind left end of dash, above micro central electric. See Fig. 8 .

Audi A4 2001 - CONTROL UNITS

Audi A4 2001 CONTROL UNITS LOCATION

Component	Component Location
ABS Control Module	In left front corner of engine compartment.
Air Bag Control Module	In center console. See Fig. 8 .
Antenna Selection Control Module	In trunk, on CD changer bracket.
Central Locking/Interior Light Delay/Anti-Theft Alarm Control Module	On bottom right of luggage compartment. See Fig. 8 .
Cruise Control, Control Module	Behind right side of dash. See Fig. 8 .
Door Warning Lights Control Module	On 8-pin relay carrier, position 5. See Fig. 6 .
Fresh Air Blower Control Module	Behind right side of dash.
Headlight Leveling Control Module	Under right side of rear seat.
Heated Door Lock Control Module (Left)	Upper part of left front door. See Fig. 8 .
Motronic Engine Control Module (ECM)	Near brake booster, in protective case. See Fig. 8 .
Power Sunroof Control Module	At center of windshield header, above headliner.
Radiator Fan Control Module	In lower right front corner of engine compartment, on frame rail.
Rear Light Control Module	On 13-pin relay carrier, position No. 4 & No. 5. See Fig. 7 .
Throttle Valve Control Module (1.8L)	On left side of engine, on intake manifold. See Fig. 1 .
Throttle Valve Control Module (2.7L)	On front of engine, on intake manifold. See Fig. 2 .
Throttle Valve Control Module (2.8L)	On rear of engine, on intake manifold. See Fig. 3 .
Transmission Control Module (TCM)	Under carpet, forward of passenger's seat. See Fig. 8 .
Ultra-Sound Sensor Control Module	Below center of rear seat. See Fig. 8 .

Audi A4 2001 - MOTORS

Audi A4 2001 MOTORS LOCATION

Component	Component Location
Airflow Flap Motor	Behind right side of dash, near blower motor.
Blower Motor	Behind right side of dash, on HVAC housing.
Central Air Flap Motor	Behind lower center of dash, near transmission tunnel.
Central Locking Motor	Below center of rear seat.
Cruise Control Vacuum Pump	In left front corner of engine compartment, near power steering reservoir.
Footwell/Defroster Flap Motor	Behind lower right center of dash, near transmission tunnel.
Fuel Pump	In fuel tank.
Headlight Washer Pump	In left front corner of engine compartment.
Leak Detection Pump	In right rear wheelhouse, above plastic liner.
Rear Windshield Wiper Motor	On center of rear hatch, behind trim panel.
Secondary Air Injection (AIR) Pump Motor (2.8L)	In lower right front corner of engine compartment.
Temperature Regulator Flap Motor	Behind lower right center of dash, near transmission tunnel.
Windshield Washer Pump	In left front corner of engine compartment.

Audi A4 2001 - SENDING UNITS & SENSORS

Audi A4 2001 SENDING UNITS & SENSORS LOCATION

Component	Component Location
ABS Wheel Speed Sensor (4)	On respective hub/spindle assembly.
Accelerator Pedal Position Sender (2.7L)	Above accelerator pedal, on bracket.
Anti-Theft Warning System Ultra-Sound Sensor (Left)	Behind top of left "B" pillar trim panel.
Anti-Theft Warning System Ultra-Sound Sensor (Right)	Behind top of right "B" pillar trim panel.
Back Pressure Flap Motor Position Sensor	Behind right side of dash, near base of "A" pillar.
Barometric Pressure Sensor	Near brake booster, in ECM protective case.
Camshaft Position (CMP) Sensor (1.8L)	On front of cylinder head, behind timing belt cover. See Fig. 1 .
Camshaft Position (CMP) Sensor Bank 2 (2.7L)	On rear of left cylinder head. See Fig. 2 .
Camshaft Position (CMP) Sensor Bank 2 (2.8L)	On rear of left cylinder head. See Fig. 3 .
Camshaft Position (CMP) Sensor 2 (2.7L)	On front of right cylinder head.
Camshaft Position (CMP) Sensor 2 (2.8L)	On front of right cylinder head. See Fig. 3 .
Center Outlet Temperature Sender	Behind lower center of dash, on HVAC unit.
Central Flap Motor Position Sensor	Behind lower right center of dash, on HVAC unit.
Charge Air Pressure Sensor (2.7L)	On center of intake manifold.
Crash Sensor For Side Air Bag (Left)	Beneath left front seat, on frame rail.
Crash Sensor For Side Air Bag (Right)	Beneath right front seat, on frame rail.
Engine Coolant Temperature (ECT) Sensor (1.8L)	At rear of cylinder head, on coolant flange. See Fig. 1 .
Engine Coolant Temperature (ECT) Sensor (2.7L)	At rear of right cylinder head, on coolant pipe. See Fig. 2 .
Engine Coolant Temperature (ECT) Sensor (2.8L)	At rear of right cylinder head, on coolant pipe. See Fig. 3 .
Engine Oil Temperature Sensor (1.8L)	On left side of engine, on oil filter housing. See Fig. 1 .
Engine Oil Temperature Sensor (2.7L)	On lower left front of engine.
Engine Oil Temperature Sensor (2.8L)	On lower left front of engine.
Engine Speed (RPM) Sensor (1.8L)	On left side of engine, near oil filter housing.
Engine Speed (RPM) Sensor (2.7L)	On left side of transmission bellhousing.
Engine Speed (RPM) Sensor (2.8L)	On left side of transmission bellhousing.
Exhaust Temperature Sender 1 (2.7L)	In outlet side of right turbocharger housing.
Exhaust Temperature Sender 2 (2.7L)	In outlet side of left turbocharger housing.
Floor Outlet Temperature Sender	Behind lower left center of dash, on HVAC unit.
Footwell/Defrost Flap Motor Position Sensor	Behind lower center of dash, above accelerator pedal.
Fresh Air Intake Duct Sensor	Behind right side of dash, near blower motor.
Fuel Gauge Sender	In fuel tank, integrated with fuel pump assembly.
Headlight Level Sensor (Front)	Attached to right front lower suspension arm.
Headlight Level Sensor (Rear)	Attached to right rear lower suspension arm.
Heated Oxygen Sensor (HO2S) (1.8L)	On right side of engine, on exhaust manifold. See Fig. 1 .
Heated Oxygen Sensor (HO2S) (2.7L)	On exhaust manifold, behind right cylinder head.
Heated Oxygen Sensor (HO2S) (2.8L)	Behind right cylinder head, on exhaust manifold.
Heated Oxygen Sensor (HO2S) 2 (2.7L)	On exhaust manifold, behind left cylinder head.
Heated Oxygen Sensor (HO2S) 2 (2.8L)	Behind left cylinder head, on exhaust manifold.
Intake Air Temperature (IAT) Sensor (1.8L)	On intake manifold, near throttle valve control module. See Fig. 1 .
Intake Air Temperature (IAT) Sensor (2.7L)	On bottom of intake manifold, behind throttle valve control module. See Fig. 2 .
Intake Air Temperature (IAT) Sensor (2.8L)	On rear of intake manifold, in intake duct.
Knock Sensor (KS) 1 (1.8L)	On left front of engine block.
Knock Sensor (KS) 1 (2.7L)	On right side of engine block, under intake manifold.
Knock Sensor (KS) 1 (2.8L)	On right side of engine block, under intake manifold.
Knock Sensor (KS) 2 (1.8L)	On left rear of engine block.
Knock Sensor (KS) 2 (2.7L)	On left side of engine block, under intake manifold.
Knock Sensor (KS) 2 (2.8L)	On left side of engine block, under intake manifold.
Mass Airflow (MAF) Sensor (1.8L)	Inside of air cleaner housing.
Mass Airflow (MAF) Sensor (2.7L)	Attached to air cleaner housing. See Fig. 2 .
Mass Airflow (MAF) Sensor (2.8L)	Attached to air cleaner housing. See Fig. 3 .
Outside Air Temperature Sensor	Behind center of lower front grille.
Oxygen Sensor Behind TWC (1.8L)	Rearward of cylinder head, in engine compartment.
Oxygen Sensor Behind TWC (2.7L) (2)	Downstream of respective TWC.
Oxygen Sensor Behind TWC (2.8L) (2)	Downstream of respective TWC.
Sunlight Photo Sensor	Inside defroster grille, on center of dashboard.
Temperature Flap Motor Position Sensor	Behind lower right center of dash, near transmission tunnel.
Throttle Position Sender (2.7L)	Above accelerator pedal, on bracket.
Transmission Vehicle Speed Sensor (VSS)	On left side of transmission, near axle flange.

Audi A4 2001 - SOLENOIDS & SOLENOID VALVES

Audi A4 2001 SOLENOIDS & SOLENOID VALVES LOCATION

Component	Component Location
Camshaft Adjustment Valve 1 (V6)	On rear of right cylinder head.
Camshaft Adjustment Valve 2 (V6)	On front of left cylinder head.
Evaporative Emissions (EVAP) Canister Purge Regulator Valve (1.8L)	On top of air cleaner housing. See Fig. 1 .
Evaporative Emissions (EVAP) Canister Purge Regulator Valve (2.7L)	On upper right side of engine, near intake duct. See Fig. 2 .
Evaporative Emissions (EVAP) Canister Purge Regulator Valve (2.8L)	On top of air cleaner housing.
Intake Manifold Tuning (IMT) Valve Changeover Valve (2.8L)	On rear of intake manifold. See Fig. 3 .
Secondary Air Injection (AIR) Solenoid Valve (2.8L)	On rear of intake manifold, near air intake duct. See Fig. 3 .
Shift Lock Solenoid	At base of gear selector lever.
Turbocharger Recirculating Valve (2.7L)	On top of engine, left of intake duct. See Fig. 2 .
Wastegate By-Pass Regulator Valve (1.8L)	In right front corner of engine compartment, attached to intake duct.
Wastegate By-Pass Regulator Valve (2.7L)	On upper right side of engine, near intake duct. See Fig. 2 .

Audi A4 2001 - SWITCHES

Audi A4 2001 SWITCHES LOCATION

Component	Component Location
A/C Pressure Switch	Below passenger side headlight.
After-Run Coolant Thermal Switch (2.7L)	On rear of left cylinder head, in coolant piping.
Brake Light Switch	Above brake pedal, on bracket.
Clutch Pedal Position Switch	Above clutch pedal, on bracket.
Clutch Vacuum Vent Valve Switch	Above clutch pedal, on bracket.
Coolant Fan Control (FC) Thermal Switch	On lower radiator hose.
Engine Coolant Level (ECL) Warning Switch	On coolant reservoir.
Hood Alarm Switch	Integral with hood latch assembly.
Kickdown Switch (2.8L)	On left center of firewall, integral with throttle cable. See Fig. 3 .
Multifunction Transmission Range (TR) Switch	On left side of transmission, behind mounting bracket.
Oil Pressure Switch (1.8L)	On lower left side of engine, on oil filter housing.
Oil Pressure Switch (2.7L)	On lower left front of engine, on oil pan extension.
Oil Pressure Switch (2.8L)	On lower left front of engine, on oil pan extension.
Trunk Lock Alarm Switch	Integral with trunk latch assembly.
Vacuum Vent Valve Brake Switch	Integral with brake light switch.

Audi A4 2001 - MISCELLANEOUS

Audi A4 2001 MISCELLANEOUS LOCATION

Component	Component Location
Alarm Horn	In rear of luggage compartment, behind trim.
Coolant Fan Control (FC) Series Resistance	On bottom of left front frame rail, in engine compartment.
Data Link Connector (DLC)	Under left side of dash.
Front Seat Belt Tensioner Ignitor (Left)	At bottom of left "B" pillar, behind trim panel.
Front Seat Belt Tensioner Ignitor (Right)	At bottom of right "B" pillar, behind trim panel.
Head-Level Air Bag Ignitor (Left)	On left "C" pillar, behind trim panel.
Head-Level Air Bag Ignitor (Right)	On right "C" pillar, behind trim panel.
Ignition Coil (4) (1.8L)	On top of cylinder head, beneath decorative cover.
Ignition Coil (6) (2.7L)	On top of respective cylinder head, beneath decorative cover.
Ignition Coil (2.8L)	On top front of engine. See Fig. 3 .
Left Connector Station	Under bottom of left "A" pillar trim. See Fig. 8 .
Power Output Stage (1.8L)	On top of air cleaner housing. See Fig. 1 .
Power Output Stage (2.7L)	On top of air cleaner housing. See Fig. 2 .
Power Output Stage (2.8L)	Integral with ignition coil.
Power Output Stage 2 (2.7L)	On top of air cleaner housing, with brown connectors. See Fig. 2 .
Rear Seat Belt Tensioner Ignitor (Center)	Behind center rear seat back.
Rear Seat Belt Tensioner Ignitor (Left)	Behind left rear seat back, behind trim panel.
Rear Seat Belt Tensioner Ignitor (Right)	Behind right rear seat back, behind trim panel.
Right Connector Station	Under bottom of right "A" pillar trim. See Fig. 8 .

Audi A4 2001 - CONNECTORS

Audi A4 2001 CONNECTORS LOCATION

Component	Component Location
T6 (Yellow, 6 Pin)	Under bottom of right "A" pillar, on connector station.
T6A (Red, 6 Pin)	Under bottom of right "A" pillar, on connector station.
T6B (Yellow, 6 Pin)	Under bottom of left "A" pillar, on connector station.
T6C (Red, 6 Pin)	Under bottom of left "A" pillar, on connector station.
T6D (Brown, 6 Pin)	Under bottom of right "A" pillar, on connector station.
T6E (Blue, 6 Pin)	Under bottom of left "A" pillar, on connector station.
T6F (Orange, 6 Pin)	Under bottom of right "A" pillar, on connector station.
T6G (Gray, 6 Pin)	Under bottom of right "A" pillar, on connector station.
T6J (Red, 6 Pin)	Under bottom of left "A" pillar, on connector station.
T6O (White, 6 Pin)	Under bottom of right "A" pillar, on connector station.
T6Q (Orange, 6 Pin)	Under bottom of left "A" pillar, on connector station.
T6Z (Red, 6 Pin)	In E-box, at left rear of engine compartment.
T8A (Black, 8 Pin)	In E-box, at left rear of engine compartment.
T10 (Brown, 10 Pin)	In E-box, at left rear of engine compartment.
T10A (Brown, 10 Pin)	Under bottom of left "A" pillar, on connector station.
T10B (Orange, 10 Pin)	Under bottom of left "A" pillar, on connector station.
T10C (Violet, 10 Pin)	Under bottom of left "A" pillar, on connector station.
T10F (Black, 10 Pin)	Under bottom of right "A" pillar, on connector station.
T10G (Brown, 10 Pin)	Under bottom of right "A" pillar, on connector station.
T10H (Brown, 10 Pin)	Under bottom of left "A" pillar, on connector station.
T10I (Black, 10 Pin)	Below rear of center console.
T10J (Green, 10 Pin)	Under bottom of left "A" pillar, on connector station.
T10K (Red, 10 Pin)	At left "B" pillar.
T10M (Black, 10 Pin)	In E-box, at left rear of engine compartment.
T10N (Red, 10 Pin)	Under bottom of right "A" pillar, on connector station.
T10O (Red, 10 Pin)	On right "B" pillar.
T10Q (Blue, 10 Pin)	Under bottom of left "A" pillar, on connector station.
T10V (Brown, 10 Pin)	Under bottom of right "A" pillar, on connector station.
T10X (Blue, 10 Pin)	Under bottom of right "A" pillar, on connector station.
T10Y (Blue, 10 Pin)	In E-box, at left rear of engine compartment.
T10Z (Yellow, 10 Pin)	In E-box, at left rear of engine compartment.

Audi A4 2001 - GROUNDS

Audi A4 2001 GROUNDS LOCATION

Component	Component Location
G3	On right front of engine.
G12	At left rear of engine compartment. See Fig. 8 .
G18	On top front of engine.
G32	Above left kick panel. See Fig. 8 .
G43	Above right kick panel. See Fig. 8 .