A/C HIGH PRESSURE SENSOR (F65)
A/C High Pressure Sensor sends a digital signal to A/C Control Module. The A/C High Pressure Sensor needs to sense a pressure between 26 psi (1.8 bar) 464 psi (32 bar) for the A/C system to turn on. The Coolant Fan Control Module (J293) regulates coolant fan speed.
AFTER-RUN COOLANT PUMP
Note. Models with 1.8L Turbo, 3.0L V6 and 4.2L V8 engines are not equipped with an After-Run Coolant Pump.
2.7 V6 Bi-Turbo
Note. After Run Coolant Pump (V51) is operated by Coolant Fan Control Module. There is no diagnostic information available from the manufacturer for Coolant Fan Control Module.
Models with 2.7 V6 Bi-Turbo engine are equipped with an After Run Electric Coolant Pump. After Run Electric Coolant Pump is operated by the Coolant Fan Control Module the system uses an After Run Electric Coolant Pump Thermo Switch (F95) as an input to the Coolant Fan Control Module (J293).
When engine is turned off and coolant temperature is above 195°F (91°C) After-Run Coolant Pump and Coolant Fan will be turned on. The After-Run Coolant Pump (V51) and No. 2 Coolant Fan (V177) are generally activated for 3 to 10 minutes about 15 seconds after ignition is shut off.
After-Run Electric Coolant Pump Thermo Switch (F95) is a single stage thermo switch. After-Run Electric Coolant Pump Thermo Switch (F95) signals the Coolant Fan Control Module (J293) to activate the After-Run Electric Coolant Pump (V51). The thermo switch is located behind left cylinder head, in coolant pipe.
Location
The Cooling system is provided with 2 coolant fans. Coolant Fan No.1 (V7) is on the left. Coolant Fan Control Module No. 1 (J293) is an integral part of the cooling fan. Coolant Fan No. 2 (V177) is on the right. Coolant Fan Control Module No. 2 (J671) is an integral part of the cooling fan.
Fan Controls
Both fans are actuated with infinitely variable control by the ECM (J220), via the corresponding radiator fan control module. Contact 66 of the engine control module is the control output for coolant Fan Control Module No. 1. Contact 104 of the engine control module is the control output for No. 2.
Fan Request From Air Conditioner
Fan request is transmitted from air conditioner operating element via CAN bus to engine control module, from where it is relayed directly to the fans.
Normal Engine Operation
In normal operation and with engine idling, fans are controlled as a function of coolant and ambient temperatures.
COOLANT FAN CONTROL MODULE
Note. No diagnostic information is available from the manufacturer. Cooling Fan Control Module (J293) always has positive battery voltage (B+) and Cooling Fan(s) has a permanent ground.
1.8L Turbo
Coolant Fan Control Module (J293) controls Coolant Fan No. 1 (V7). Coolant Fan Control Modules utilizes input from ECM (J220) and A/C Control Head (E87).
2.7L V6 Bi-Turbo
Coolant Fan Control Module (J293) controls Coolant Fans No.1 (V7) and No. 2 (V177) and After-Run Coolant Pump (V51). Coolant Fan Control Module (J293) utilizes input from Coolant Fan Control Thermo Switch, After-Run Coolant Pump Thermo Switch (F95), A/C Control Head (E87) and ECM (J220).
3.0L V6
Coolant Fan Control Module (J293) controls Coolant Fan No. 1 (V7). Coolant Fan Control Modules utilizes input from ECM (J220) and A/C Control Head (E87).
4.2L V8
Coolant Fan Control Module (J293) controls Coolant Fan No. 1 (V7). Coolant Fan Control Module No. 2 (J671) controls Coolant Fan No. 2 (V177). Coolant Fan Control Modules utilizes input from ECM (J220) and A/C Control Head (E87).
2.7L V6 Bi-Turbo & 4.2L V8
Coolant Fan Control Thermo Switch is a 2-stage thermo switch. At a preset temperature, (Coolant Fan Thermo Switch specific) Coolant Fan Thermo Switch completes a ground circuit to the Coolant Fan Control Module (J293). The first ground signal is to actuate Coolant Fan No.1 (V7). At a higher preset temperature Coolant Fan Thermo Switch completes a second ground circuit to the Coolant Fan Control Module (J293). The second ground signal is to actuate Coolant Fan No.2 (V177).
COMPONENT LOCATIONS
| Component | Location | |
|---|---|---|
| A/C High Pressure Sensor (F65) | ||
| All Models | Right Front Corner Of Engine Compartment, Lower Left. (Scheme 1) | |
| After Run Coolant Pump (2.7L V6 Bi-Turbo) | Under Vehicle, Behind Left Side Of Oil Pan. (Scheme 2) | |
| After Run Coolant Pump Thermo Switch (2.7L V6 Bi-Turbo) | Behind Left Cylinder Head, In Coolant Pipe. (1) | |
| Climatronic (Auto A/C) Control Module (E87) | Integrated with A/C Control Panel | |
| Coolant Fan Control Module (J293) | ||
| 2.7L V6 Bi-Turbo | Front Of Engine Compartment, Lower Left. (Scheme 3) | |
| 3.0L V6 & 4.2L V8 | Front Of Engine Compartment, Upper Left. (Scheme 4) | |
| Coolant Fan Ground Point | ||
| 2.7L V6 Bi-Turbo | Left Lower A Pillar | |
| 3.0L V6 & 4.2L V8 | Front Apron, Left Side Of Engine. (Scheme 5) | |
| Coolant Fan Thermo Switch (2.7L V6 Bi-Turbo) | In Lower Right Corner In Radiator Hose/Tube Fitting Close To Radiator Tank. (Scheme 6) | |
| Eight-Fold Auxiliary Relay Panel (2.7L V6 Bi-Turbo) | Under Left Side Of Dash, Behind Trim Panel. (Scheme 7) | |
| Fuse Locations | ||
| 2.7L V6 Bi-Turbo | Eight-Fold Auxiliary Relay Panel. (Scheme 7) (2) | |
| 3.0L V6 & 4.2L V8 | Four Fold Relay Panel - Instrument Panel. (Scheme 8) | |
| 3.0L V6 & 4.2L V8 | Four Fold Relay Panel - E-Box. (Scheme 9) | |
| (1) Only models with the 2.7L V6 Bi-Turbo engine use an After Run Coolant Pump Thermo Switch (F95) and After Run Coolant Pump Thermo Switch Relay (J151). (2) Fuse locations on Eight Fold Relay Panel. For Coolant Fan Control Module (J293). Models with the 2.7L Bi-Turbo engine; for MY 2002 fuse position is No. 20 Coolant Fan (60A), for MYs 2003 and 2004 fuse position is No. 19 Coolant Fan (60A). | ||
| (1) | Only models with the 2.7L V6 Bi-Turbo engine use an After Run Coolant Pump Thermo Switch (F95) and After Run Coolant Pump Thermo Switch Relay (J151). |
| (2) | Fuse locations on Eight Fold Relay Panel. For Coolant Fan Control Module (J293). Models with the 2.7L Bi-Turbo engine; for MY 2002 fuse position is No. 20 Coolant Fan (60A), for MYs 2003 and 2004 fuse position is No. 19 Coolant Fan (60A). |
COMPONENT LOCATIONS
Scheme 1
Scheme 2
Scheme 3
Scheme 4
Scheme 5
Scheme 6
Scheme 7
Scheme 8
Scheme 9
SYSTEM TESTS
System testing information is not available from manufacturer for all components. To assist in circuit diagnosis, see WIRING DIAGRAMS . Ensure all fuses are okay before proceeding with any testing. If a fuse is blown, check for a short circuit and repair before replacing fuse.
A/C HIGH PRESSURE SENSOR
The 3-wire sensor pin values are as follows
- Pin 1: Ground
- Pin 2: Duty Cycle signal to A/C Control Head (E87)
- Pin 3: Power when ignition is on (15+)
Duty cycle reading can be used to diagnose A/C high pressure sensor. Turn ignition on, with engine off. See A/C HIGH PRESSURE SENSOR SPECIFICATIONS table.
| Duty Cycle | Possible Cause | Corrective Action |
|---|---|---|
| 12 % to 87.5% | Sensor OK | None. Sensor reading is normal. |
| 88% | Faulty Sensor | Replace Sensor |
| 11% | Low Refrigerant | Recharge A/C System |
| 11% | Faulty Sensor | (1) Replace Sensor |
| (1) Ensure refrigerant system is fully charged before assuming sensor is faulty. | ||
| (1) | Ensure refrigerant system is fully charged before assuming sensor is faulty. |
A/C HIGH PRESSURE SENSOR SPECIFICATIONS
COOLANT FAN
Note. There is no Coolant Fan diagnostic information available from the manufacture for the 1.8L Turbo and 3.0 L V6 engines.
| CAUTION | When working with electronics in the cooling system, be aware that the secondary speed coolant fan relay or Cooling Fan Control Module always have positive battery voltage (B+) and Cooling Fan has a permanent ground. Coolant Fan can start automatically. |
Note. There is no diagnostic information available from the manufacturer for Coolant Fan Control Module.
- Ensure fuses No. 34 and 42 are okay. (Scheme 25) Ensure Coolant Fan Control Thermal Switch is okay. See «COOLANT FAN CONTROL THERMO SWITCH PERFORMANCE»(/audi/a4/b6-2000-2006/remont/cooling-fan/#electric-cooling-fans) and «COMPONENT LOCATIONS»(/audi/a4/b6-2000-2006/remont/cooling-fan/#electric-cooling-fans) table.
- Switch ignition on. Bridge terminal No. 1 and terminal No. 2 of harness connector using auxiliary cables VW1594. Coolant fan -V7- must run on 1st speed. Bridge terminal No. 3 and terminal No. 4 of 4 pin harness connector using auxiliary cables from VW1594. (Scheme 10) Coolant fan (V7) must run on 2nd speed. If 1st or 2nd fan speed does not run. Locate and repair open circuit using wiring diagram. See «WIRING DIAGRAMS»(/audi/a4/b6-2000-2006/remont/cooling-fan/#electric-cooling-fans). If no open circuit can be found. Replace coolant fan (V7).
Scheme 10
Scheme 11
Scheme 12
Scheme 13
- Connect up vehicle diagnostic, testing and information system VAS 5051. (Scheme 11) Turn ignition on and select vehicle system "01 Engine electronics" from list.
- Indicated on VAS 5051: (Scheme 12) From list 1 select diagnostic function "03 Final control diagnosis". Touch "right arrow key" key, until the radiator exhaust control No. 2 is activated. Coolant fan control module No. 2 (J671) slowly switches coolant fan No. 2 (V177) (right fan) once up to full speed. Touch "right arrow key" until the radiator exhaust control 1 is activated. Coolant Fan Control module J293 slowly switches coolant fan V7 (left fan) once up to full speed. Terminate function "03 Final control diagnosis" by touching "left arrow key".
- If fan actuation does not react as described: Based on the previously mentioned criteria, create preconditions for radiator fan start-up (e.g. switch on air conditioner, increase engine temperature accordingly).
- Indicated on VAS 5051: (Scheme 12) From list 1 select diagnostic function "08 Reading measured value block".
- Indicated on VAS 5051: (Scheme 13) 1 Enter display group. Use keypad 2 to enter "135" for "Display group number 135" and confirm by touching Q key.
- Indicated on VAS 5051: (Scheme 14) Check display in zones 2 and 3. Duty cycle of fan 1 (left): min. 10%. Duty cycle of fan 2 (right): min. 10%. If duty cycle does not increase to above 10%, read out fault memory of ECM (J220). Eliminate any faults displayed. If relevant fan does not start up although duty cycle is above 10%: Check coolant fan (V7) or coolant fan 2 (V177). See «Coolant Fan (V7, Left)»(/audi/a4/b6-2000-2006/remont/cooling-fan/#electric-cooling-fans__coolant-fan-v7-left) or «Coolant Fan (V177, Right)»(/audi/a4/b6-2000-2006/remont/cooling-fan/#electric-cooling-fans).
Scheme 14
Scheme 15
Scheme 16
Scheme 17
Scheme 18
- Checking Coolant fan -V7- (left) Requirements Coolant fan fuses and coolant fan control module OK. Remove cover -1- on left of engine compartment. (Scheme 15)
- Take connector -1- out of holder and disconnect. (Scheme 16) Connect multimeter for voltage measurement. Connector contact No. 1 to Engine Ground. (Scheme 17) Connector contact to No. 4 to Battery positive. Specification: about battery voltage.
- If readings do not match specifications: Use wiring diagram to eliminate open circuit in wiring. See «WIRING DIAGRAMS»(/audi/a4/b6-2000-2006/remont/cooling-fan/#electric-cooling-fans).
- If readings match specifications: Connect multimeter for voltage measurement. Connect harness connector terminal 2 to Engine ground. Specification: about battery voltage. If reading does not match specification, eliminate open circuit in wiring.
- If readings match specifications: Connect multimeter for voltage measurement between contacts 2 and 3 of connector. (Scheme 16) Vehicle diagnostic, testing and information system VAS 5051 connected; vehicle self-diagnosis and vehicle system "01 Engine electronics" selected. Ignition must be on.
- Indicated on VAS 5051: (Scheme 12) From list 1 select diagnostic function "03 - Final control diagnosis". Keep touching "right arrow key" until the radiator exhaust control -1- is activated. Voltage value must slowly drop from about battery voltage to roughly 8 V (and then increase again). Terminate function "03 Final control diagnosis" by touching "left arrow key". Switch ignition off.
- If the specified value is not reached: Connect test box V A G 1598/31 to wiring harness connectors. (Scheme 24) Engine control module is not to be connected. Connect ground clip of test box to ground. Check for open circuit and short to ground/positive in the following wiring. Wiring harness connector terminal 4 and Test Box V.A.G 1598/31 socket 66. (Scheme 16) Use wiring diagram to eliminate open circuit in wiring/short circuit. See «WIRING DIAGRAMS»(/audi/a4/b6-2000-2006/remont/cooling-fan/#electric-cooling-fans).
- If no fault is found, remove front bumper. Connect multimeter with prods and plug-in adapters from V.A.G 1594 A between contacts 1 and 2 of brown connector at Coolant fan control module -J293-. Leave harness connector attached. (Scheme 18) Vehicle diagnostic, testing and information system VAS 5051 connected; vehicle self-diagnosis and vehicle system "01 - Engine electronics" selected. Ignition must be on.
- Indicated on VAS 5051: (Scheme 12) From list -1- select diagnostic function "03 - Final control diagnosis". Keep touching "right key" until coolant fan control module 1 is activated. Voltage value must increase to about 10.5 V (and then decrease again). Terminate function "03 - Final control diagnosis" by touching "left key". Touch "06 - End of output". Switch off ignition.
- If reading matches specification, but fan does not run: Replace Coolant fan -V7-. See «COOLANT FAN (V7, Left)»(/audi/a4/b6-2000-2006/remont/cooling-fan/#electric-cooling-fans), under REMOVAL & INSTALLATION. If reading does not match specification: Use wiring diagram to check wiring from harness connector at front left of engine compartment to Coolant fan control module -J293-. See «WIRING DIAGRAMS»(/audi/a4/b6-2000-2006/remont/cooling-fan/#electric-cooling-fans). If no fault is found: Replace Coolant fan control module -J293-.
Scheme 19
Scheme 20
Scheme 21
- Checking Coolant fan No. 2 -V177- (right). Requirements, coolant fan fuse OK. Remove front bumper. Connect multimeter with prods and plug-in adapters from V.A.G 1594 A, between contacts 1 and 2; leave connector for Coolant fan -2-, -V177- attached. (Scheme 19) Vehicle diagnostic, testing and information system VAS 5051 connected; vehicle self-diagnosis and vehicle system "01 - Engine electronics" selected. Ignition must be on.
- Indicated on VAS 5051: (Scheme 12) From list -1- select diagnostic function "03 - Final control diagnosis". Keep touching "right arrow" key until coolant fan control module 2 is activated. Voltage value must increase to about 9 V. If reading matches specification, but fan does not run, replace Coolant fan No. 2 -V177-.
- If reading does not match specification, move lock carrier to service position. Unscrew Coolant fan control module No. 2 -J671- at front left longitudinal member (arrows). (Scheme 20) Disconnect connector -2- at coolant fan control module No. 2. Connect multimeter for voltage measurement as follows. Harness connector, terminal 1 to Battery positive. Terminal 2 to Engine Ground. (Scheme 21) Specification: about battery voltage.
- If readings do not match specifications, eliminate open circuit in wiring. See «WIRING DIAGRAMS»(/audi/a4/b6-2000-2006/remont/cooling-fan/#electric-cooling-fans). If readings match specifications: Disconnect connector -1- at Coolant fan control module 2 -J671-. (Scheme 20) Connect multimeter for voltage measurement between contacts 1 and 2 of connector. (Scheme 22) Vehicle diagnostic, testing and information system VAS 5051 connected; vehicle self-diagnosis and vehicle system "01 - Engine electronics" selected. Ignition must be on.
- Indicated on VAS 5051: (Scheme 12) From list -1- select diagnostic function "03 - Final control diagnosis". Keep touching "right arrow" key until coolant fan control module 2 is activated. Voltage value must slowly drop from about battery voltage to roughly 8 V (and then increase again). Terminate function "03 - Final control diagnosis" by touching "left arrow" key.
- If reading does not match specification: Connect test box V.A.G 1598/31 to wiring harness connectors. (Scheme 24) Actual engine control module is not to be connected. Connect Ground clip of test box to Ground.
- Check for open circuit and short to Ground/positive in wiring harness connector terminal 2 and Test Box V.A.G 1598/31 socket 104. Eliminate open circuit in wiring/short circuit. See «WIRING DIAGRAMS»(/audi/a4/b6-2000-2006/remont/cooling-fan/#electric-cooling-fans). If no fault is found: Checking wiring from Coolant fan control module No. 2 -J671- to connector at longitudinal member (arrow). (Scheme 23)and «WIRING DIAGRAMS»(/audi/a4/b6-2000-2006/remont/cooling-fan/#electric-cooling-fans). If no fault is found in wiring: Replace Coolant fan control module No. 2 -J671-.
Scheme 22
Scheme 23
| Application & Terminal | Switch Condition | Temperature °F (°C) | ||
|---|---|---|---|---|
| 2.7L V6 Bi-Turbo | ||||
| Stage One | ||||
| Terminal No. 2 | On | 197-206 (92-97) (1) | ||
| Terminal No. 2 | Off | 183-195 (84-91) | ||
| Stage Two | ||||
| Terminal No. 4 | On | 210-221 (99-105) (1) | ||
| Terminal No. 4 | Off | 195-208 (91-98) | ||
| (1) Ground signal should be present in this temperature range. | ||||
| (1) | Ground signal should be present in this temperature range. |
COOLANT FAN CONTROL THERMO SWITCH PERFORMANCE
Note. The Coolant Fan Control Module controls the Coolant Fan(s) and the After-Run Coolant Pump (2.7L Bi-Turbo only). There is no diagnostic information available from the manufacturer for Coolant Fan Control Module(s).
| CAUTION | The Coolant Fan Control Module controls the Coolant Fan(s) and the After-Run Coolant Pump. There is no diagnostic information available from the manufacturer for Coolant Fan Control Module. |
Scheme 24
- Fuses No. 34 and 42 must be OK. Main Fuse panel is behind access cover on far left side of dash. (Scheme 25)
- Start engine and idle briefly. Switch ignition off.
- After-run coolant pump must start after about 15 seconds. If pump does not run, disconnect 2-pin connector from pump. Attach multimeter for measuring voltage to contacts 1 and 2 of connector. Reading should be 11-15 V. If voltage reading is okay, go to next step. If no voltage is present, go to step 6.
- If the specification is obtained, replace after run coolant pump. Remove noise insulation panel and drain coolant. See «DRAINING, FILLING & BLEEDING»(ref-162507-S33759129822004060300000) in COOLING SYSTEMS article.
- Remove After-Run Pump. (Scheme 2)
- Check Cooling Fan Control Module harness connector for corrosion and good connection. (Scheme 2) Check Coolant Fan Control Thermo Switch harness connector for corrosion and good connection. (Scheme 6) Check A/C High Pressure Sensor harness connector for corrosion and good connection. (Scheme 1) If harness connections are okay, go to next step. If harness connections are not okay, repair as necessary.
- Check Coolant Fan Control Thermo Switch. (Scheme 6)and «COOLANT FAN CONTROL THERMO SWITCH PERFORMANCE»(/audi/a4/b6-2000-2006/remont/cooling-fan/#electric-cooling-fans) table. If switch is not okay, replace faulty switch.
AFTER RUN COOLANT PUMP THERMO SWITCH (2.7L BI-TURBO)
After Run Coolant Pump Thermo Switch is a single stage thermal switch. The ground wire is brown and the wire going to the Coolant Fan Control Module is brown/red. See WIRING DIAGRAMS .
Removal (1.8L Turbo, Coolant Fan V7)
Note. Always replace gaskets and sealing rings.
Remove front bumper. Move lock carrier to service position. Drain off coolant. See COOLING SYSTEM, DRAINING AND FILLING. Remove radiator. Disconnect connectors -1- and -2- and move fan motor wires clear. (Scheme 26) Unbolt radiator fan (arrows) from radiator cowl. (Scheme 27)
Installation (1.8L Turbo, Coolant Fan V7)
Install in reverse order, paying attention to the following: Install front bumper.
Scheme 25
Scheme 26
Note. There is no removal and installation information available from the manufacturer for the Coolant Fans.
Coolant Fan (V7, Left)
Note. All cable ties unfastened or cut open on removal are to be re-attached in same position on installation.
Removal
- Move lock carrier to service position. See appropriate Engine Mechanical article. Disconnect connector (arrow) at Coolant fan control module -J293-. (Scheme 28)
- Move wiring harness clear of radiator fan. Remove bolts (arrows) (Scheme 29)and take out fan.
Scheme 27
Scheme 28
Installation
Note. Re-attach all cable ties at same location on installation.
- Install in reverse order, paying attention to the following. Install lock carrier with attachments. See appropriate Engine Mechanical article. Allow stop for torque reaction support to settle on rubber buffer for torque reaction support and tighten bolts to 21 ft. lbs. (28 N.m). (Scheme 30) Install front bumper. Adjust headlights.
- Tighten coolant fan to lock carrier 89 INCH lbs. (10 N.m).
Scheme 29
Note. All cable ties unfastened or cut open on removal are to be re-attached in same position on installation.
- Move lock carrier to service position. Disconnect connector (arrow). (Scheme 23)
- Move wiring harness to coolant fan clear. Remove bolt -1-. see scheme 31 Turn coolant fan in direction of arrow and remove. see scheme 31
Scheme 30
Note. Re-attach all cable ties at same location on installation.
- Install in reverse order, paying attention to the following: Install lock carrier with attachments. See appropriate Engine Mechanical article. Allow stop for torque reaction support to settle on rubber buffer for torque reaction support and tighten bolts to 21 ft. lbs. (28 N.m). Install front bumper. Adjust headlights.
- Tighten coolant fan to lock carrier 89 INCH lbs. (10 N.m).
TORQUE SPECIFICATIONS
| Application | Ft. Lbs. (N.m) |
|---|---|
| Coolant Fan Control Thermo Switch | 26 (35) |
| INCH Lbs. (N.m) | |
| A/C High Pressure Sensor | (1) 44 (5) |
| (1) A/C refrigerant does not need to be discharged. Use new "O" ring. | |
| (1) | A/C refrigerant does not need to be discharged. Use new "O" ring. |
TORQUE SPECIFICATIONS
2002
See COOLING FAN in SYSTEM WIRING DIAGRAMS in ELECTRICAL.
2003
See COOLING FAN in SYSTEM WIRING DIAGRAMS in ELECTRICAL.
2004
See COOLING FAN in SYSTEM WIRING DIAGRAMS in ELECTRICAL.