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HOMESERVICE MANUALSAUDI2005TT QUATTRO, 2D COUPE, 3.2 FREPAIR AND DIAGNOSISHEATING, VENTILATION & A/C (HVAC)HVAC CONTROL SYSTEMSHEATING & AIR CONDITIONING01 ON BOARD DIAGNOSTIC (OBD)AUTOMATIC CLIMATE CONTROL SYSTEM, ELECTRICAL TESTINGCOOLANT FAN CONTROL (FC) MODULE -J293-, ELECTRICAL TESTINGNOTES

2005 Audi TT Quattro, 2D Coupe, 3.2 F

Coolant Fan Control (FC) Module -J293-, electrical testing: Notes

2005 Audi TT Quattro, 2D Coupe, 3.2 FSECTION Notes

Special tools, testers and auxiliary items

Multimeter (Fluke 83 or equivalent)
VW 1594 connector test kit
VAG 1527B voltage tester (or equivalent diode type tester)
VAS 5051 Vehicle Diagnostic Testing and Information System for testing square wave (pressure) signal on vehicles with high pressure sensor -G65-.

Test conditions

All fuses OK according to wiring diagram
DTC memory of A/C Control Head -E87- checked - no DTCs stored.
No compressor shut-off conditions displayed in read measuring value block (Display Group 01, display field 1) for A/C Control Head -E87- while engine is running.
A/C Control Head -E87- installed.

Connectors A and B detached from -J293-.

Coolant Fan Control (FC) Module -J293- (vehicles with A/C pressure switch -F129-), electrical testing

Fig 1: Terminal Assignments At -J293- (Vehicles With -F129-)

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Terminal assignments at -J293- (vehicles with -F129-)

Location: In engine compartment on left long member.

Function:

Activates coolant fan(s) -V7- (speeds 1 and 2)
Activates A/C clutch -N25-.

NOTE: The function of -J293 and vehicle wiring layout will vary depending on whether vehicle is equipped with A/C pressure switch -F129 or high pressure sensor -G65-.

Refer to Electrical Wiring Diagrams, Troubleshooting & Component Locations.

Fig 2: Identifying High/Low Pressure Switch

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Terminal assignments and switching conditions (A/C pressure switch -F129-)

Switch between terminals -1- and -2- opens if there is excess pressure or insufficient refrigerant system pressure (A/C clutch -N25- is disengaged).
Switch between terminals -3- and -4- closes when refrigerant system pressure rises (coolant fan(s) -V7- switched to speed 2).

Switching conditions - Coolant Fan Control (FC) Thermoswitch -F18/-F54

-F54 between terminals 1 and 2: Closes at approx. 95 °C (-V7- switched to speed 1).
-F18 between terminals 3 and 2: Closes at approx. 102 °C (-V7- switched to speed 2).

Switching conditions - Engine Coolant Temperature (ECT) Waring Switch -F14-

Switch opens at approx. 118 °C - compressor is switched off.

NOTE: -F14- is only installed on vehicles with A/C pressure switch -F129-.

Refer to Electrical Wiring Diagrams, Troubleshooting & Component Locations.

Test step 1 - Voltage supply, Ground (GND) supply

Voltage test - switch to 20 V measuring range
Test step	-J293- connectors/terminals	Test of	Test conditions Additional operations	Specified Value	Corrective action
1.1	B/3 + A/6	Voltage supply		Approx. B+	Trace and repair voltage supply and/or Ground (GND) connection according to wiring diagram.
1.2	B/4 + A/6	Voltage supply		Approx. B+	Trace and repair voltage supply according to wiring diagram.
1.3	A/4 + A/6	Voltage supply		Approx. B+	Trace and repair voltage supply according to wiring diagram.
1.4	A/9 + A/6	Voltage supply	Ignition switched on	Approx. B+	Trace and repair voltage supply according to wiring diagram.

Test step 2 - Activation of coolant fan(s) -V7-

Voltage test - switch to 20 V measuring range
Test step	-J293- connectors/terminals	Test of	Test conditions Additional operations	Specified Value	Corrective action
2.1	A/5 + A/6	-V7- speed 1 signal from A/C Control Head -E87- (activated by -E87-)	Engine running -E87- in "AUTO" mode (A/C clutch -N25- engaged)	Approx. B+	Trace and repair open/short circuit to GND in wiring/connections between -J293- and -E87- according to wiring diagram. Replace -E87-.
2.2	A/2+ A/6	-V7- speed 2 signal from -E87- (activated by A/C pressure switch -F129-)	Harness connector disconnected from -F129-, terminals 3 and 4 bridged Switch ignition on	Approx. B+	Trace and repair voltage supply to -F129- according to wiring diagram. Trace and repair open circuit in wiring/connectors between -F129- and -J293- according to wiring diagram.

Test step 2 continued:

Voltage test - switch to 20 V measuring range
Test step	-J293- connectors/terminals	Test of	Test conditions Additional operations	Specified Value	Corrective action
2.3	Connectors A + B connected to -J293-	-V7- speed 2 (activated by A/C pressure switch -F129-)	Harness connector disconnected from -F129-, connector terminals 3 and 4 bridged Ignition switched on	-V7- runs (speed 2)	Trace and repair voltage supply to -F129- according to wiring diagram. Trace and repair open circuit in wiring/connectors between -J293- and fan(s) -V7- according to wiring diagram. Replace -V7-. Replace -J293-.
2.4	B/2 + A/6	-V7- speed 1 signal from -E87- (activated by Coolant Fan Control (FC) Thermoswitch -F54-	Harness connector disconnected from -F18-/-F54-, terminals 1 and 2 bridged Switch ignition on	Approx. B+ -V7- runs (speed 1)	Trace and repair voltage supply to -F54- according to wiring diagram. Trace and repair open circuit in wiring/connectors between -F54- and -J293- according to wiring diagram. Trace and repair open circuit in wiring/connectors to -V7- according to wiring diagram. Replace -V7-.

Test step 2 continued:

Voltage test - switch to 20 V measuring range
Test step	-J293- connectors/terminals	Test of	Test conditions Additional operations	Specified Value	Corrective action
2.5	A/7 + A/6	-V7- speed 2 signal from -E87- (activated by Coolant Fan Control (FC) Thermoswitch -F18-)	Harness connector disconnected from -F18-/-F54-, terminals 2 and 3 bridged Switch ignition on	Approx. B+	Trace and repair voltage supply to -F18- according to wiring diagram. Trace and repair open circuit in wiring/connectors between -F18- and J293- according to wiring diagram.
2.6	Connectors A + B connected to -J293-	-V7- speed 2 signal from -E87- (activated by Coolant Fan Control (FC) Thermoswitch -F18-)	Harness connector disconnected from -F18-/-F54-, terminals 2 and 3 bridged Switch ignition on	Approx. B+ -V7- runs (speed 2)	Trace and repair open circuit in wiring/connectors to -V7- according to wiring diagram. Trace and repair open circuit in wiring/connectors between -J293- and fan(s) -V7- according to wiring diagram. Replace -V7-. Replace -J293-.

Test step 3 - Activation of A/C clutch -N25-

Voltage test - switch to 20 V measuring range

Test step

-J293- connectors/terminals

Test of

Test conditions

Additional operations

Specified
Value

Corrective action

3.1

A/8 + A/6

Signal from A/C Control Head -E87- ("activate A/C clutch -N25-")

Engine running
-E87- in "AUTO" mode

No A/C clutch -N25- shut-off conditions in read measuring value block for -E87- (Display Group 001).

Approx. B+

Trace and repair open/short circuit to GND in wiring/connections between A/C pressure switch -F129-, -F14- and -J293- according to wiring diagram.
-F14- malfunctioning (open, or excessive coolant temperature. Check. Refer to Electrical Wiring Diagrams, Troubleshooting & Component Locations.

Test step 3 continued:

Current test - switch to 20 A measuring range

Test step

-J293- connectors/terminals

Test of

Test conditions

Additional operations

Specified
Value

Corrective action

3.2

A/4 + A/10

Activation of A/C clutch -N25-

Ignition switched on

< 10 amp
-N25- clicks when voltage applied

Trace and repair open/short circuit to GND in wiring/connections between -J293- and -N25- according to wiring diagram.
-Open circuit in wiring/connection to GND for -N25-. Check. Refer to Electrical Wiring Diagrams, Troubleshooting &Component Locations.

Replace -N25-.

Coolant Fan Control (FC) Module -J293- (vehicles with high pressure sensor -G65-), electrical testing

Fig 3: Terminal Assignments At -J293- (Vehicles With -G65-)

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Terminal assignments at -J293- (vehicles with -G65-)

Location: In engine compartment on left long member

Function:

Activates coolant fan (s) -V7 (speeds 1 and 2)
Activates A/C clutch -N25
Processes the square-wave signal from high pressure sensor -G65- and sends a positive signal to -E87- to indicate the refrigerant system pressure is OK.
Switches on after-run coolant pump -V51 (if equipped) for continued coolant circulation when the ignition is switched on. The pump continues to operate for a short time after the ignition has been switched off.

NOTE:

The following -J293- connector A terminals are vacant:

Terminal 1 (on vehicles without after-run coolant pump -V51-)

Terminals 3, 5, 11 and 14

Refer to Electrical Wiring Diagrams, Troubleshooting & Component Locations

-J293- connector A,, terminal 13 is intended for disengaging -A/C clutch -N25- when the instrument cluster sends "excessive coolant temperature" signal. As disengagement of -N25- also takes place via the A/C Control Head -E87-, -J293- terminal 13 may be vacant on some vehicles, dependant of vehicle wiring configuration.

Refer to Electrical Wiring Diagrams, Troubleshooting & Component Locations

The function of Coolant Fan Control (FC) Module -J293 and vehicle wiring layout will vary depending on whether vehicle is equipped with A/C pressure switch -F129 or high pressure sensor -G65-.

Refer to Electrical Wiring Diagrams, Troubleshooting & Component Locations

Various versions of Coolant Fan Control (FC) Module -J293-, used in conjunction with high pressure sensor -G65- may be installed. At the time of publishing however, All TT equipped with -J293-/-G65- have version where coolant fan(s) -V7- speed 1 is always switched on automatically whenever the A/C clutch -N25- is energized (regardless of refrigerant system pressure).

Fig 4: Terminal Assignments And Switching Conditions (High Pressure Sensor -G65-)

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Terminal assignments and switching conditions (high pressure sensor -G65-)

Terminal -1- Ground (GND)

Terminal -2- Signal output (square-wave signal to -J293- and ECM)

Terminal -3- Positive (terminal 15)

NOTE:

When electrical connector at -B- is disconnected, the A/C clutch -N25- cannot be activated.
High pressure sensor -A- transmits a square-wave signal at a pulse rate that varies according to the refrigerant system pressure. Checking. Refer to High pressure sensor -G65- signal, checking .

Switching conditions - Coolant Fan Control (FC) Thermoswitch -F18/-F54

-F54- between terminals 1 and 2: Closes at approx. 95 °C (-V7- switched to speed 1).
-F18- between terminals 3 and 2: Closes at approx. 102 °C (-V7- switched to speed 2).

RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.
• Brakes feel soft, pull hard to one side, or make grinding noises.
• The engine overheats, stalls repeatedly, or misfires under load.
• You are missing required tools, torque specs, or safe lifting equipment.
• You are not confident in the next step or safety outcome.