Fuel Gauge And Engine Coolant Temperature Gauge, Troubleshooting

Fuel gauge, inaccurate or does not work

Courtesy of AUDI OF AMERICA, LLC

All fuses OK according to wiring diagram

-- Open trunk and remove screws from fuel tank cover-- Remove fuel tank cover-- Remove connector (arrow) from fuel level sensor-- Using connector test kit VW 1594, connect tester VW 1301 to fuel level sensor connector as shown-- Set VW 1301 to 58 (corresponds to approx. 40 ohms (Ω) resistance)-- Switch ignition ON

Fuel gauge must read full (approx. 21.1 gallons, 80 liters)

Yes

Fuel Level Sensor faulty

Go to A

-- Replace Fuel Level Sensor

End

Leave tester VW 1301 connected to fuel level sensor connector and tester value set to 58

-- Remove instrument cluster INSTRUMENT CLUSTER -- Disconnect red and green 26-point connectors from instrument cluster-- Check connectors for bent terminals, repair as necessary-- Connect adapter harness : VAG1598/4 to red 26-point instrument cluster connector-- Reconnect green 26-point connector to instrument cluster-- Set digital multimeter (Fluke 83 or equivalent) to measure resistance (Ω)-- Connect multimeter between sockets 10 and 3 of VAG 1598 test box

Must be 40-50 ohms (Ω)

Yes

No, ∞ Ω (no continuity) is displayed

Go to B

-- Check wiring to fuel level sensor for open circuit according to wiring diagram, repair as necessary

End

Leave tester VW 1301 connected to fuel level sensor connector
Keep VW 1301 set to 58

-- Set digital multimeter (Fluke 83 or equivalent) to volt range

-- Connect multimeter between socket 10 (-) of VAG 1598 test box and fuel gauge terminal -1- → illustration 90-864

Must be 0-4.5 V

Yes

No, over 4.6V displayed

Fuel gauge faulty

Printed circuit board faulty

-- Replace fuel gauge FUEL GAUGE

-- Replace printed circuit board PRINTED CIRCUIT

End

Engine Coolant Temperature (ECT) gauge, inaccurate or does not work

All fuses OK according to wiring diagram

Courtesy of AUDI OF AMERICA, LLC

-- Remove connector from electronic Engine Coolant Temperature (ECT) thermal switch -F76-

Thermal switch located on coolant pipe behind right cylinder head

-- Connect tester VW 1301 between terminal T of thermal switch connector and Ground (GND)-- Set VW 1301 to 58

Value 58 on VW 1301 corresponds to approx. resistance 40 ohms (Ω)

-- Switch ignition ON

Engine coolant temperature gauge must display approx. 230°F (110°C)

Yes

Electronic Engine Coolant Temperature (ECT) thermal switch -F76- faulty

-- Replace electronic thermal switch

End

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Leave VW 1301 connected between terminal T of electronic thermal switch connector and GND, keep VW 1301 set to 58

-- Remove instrument cluster INSTRUMENT CLUSTER -- Disconnect red and green 26-point connectors from instrument cluster-- Check connectors for bent terminals, repair as necessary-- Connect adapter harness : VAG1598/4 to green 26-point instrument cluster connector-- Reconnect red 26-point connector to instrument cluster-- Set digital multimeter (Fluke 83 or equivalent) to measure resistance (Ω)-- Connect multimeter between sockets 11 and 16 of VAG 1598 test box

Must be approx. 40 ohms (Ω)

Yes

No, ∞ Ω (no continuity) is displayed

Go to A

-- Check wiring to electronic Engine Coolant Temperature (ECT) thermal switch for open circuit according to wiring diagram, repair as necessary

End

-- Remove adapter harness : VAG1598/4 from instrument cluster (green connector)-- Remove cover from rear of instrument cluster COVER -- Reconnect adapter harness : VAG1598/4 to green 26-point instrument cluster connector-- Set digital multimeter (Fluke 83 or equivalent) to measure resistance (Ω)-- Connect multimeter to Engine Coolant Temperature (ECT) gauge terminals -1- and -2- → illustration 90-865

Must be approx. 40 ohms (Ω)

Yes

No, ∞ Ω (no continuity) is displayed

Printed circuit board faulty

ECT gauge faulty

-- Replace printed circuit board PRINTED CIRCUIT

-- Replace ECT gauge COOLANT TEMPERATURE GAUGE

End

Fuel gauge and Engine Coolant Temperature (ECT) gauge, both inaccurate or do not work

All fuses OK according to wiring diagram

-- Remove instrument cluster INSTRUMENT CLUSTER -- Remove red and green 26-point connectors from instrument cluster-- Check connectors for bent terminals, repair as necessary-- Connect adapter harness : VAG1598/4 to red 26-point instrument cluster connector-- Connect adapter harness to VAG 1598 test box-- Reconnect green 26-point connector to instrument cluster-- Set multimeter (Fluke 83 or equivalent) to volt range-- Connect multimeter between sockets 10 (-) and 11 (+) of VAG 1598 test box-- Switch ignition ON

Must be approx. 12 V

Yes

Go to A

-- Check wiring for open circuit according to wiring diagram, repair as necessary

End

-- Switch ignition OFF-- Connect multimeter (Fluke 83 or equivalent) between terminals -1- (+) and -2- (-) of voltage stabilizer → illustration 90-1123-- Switch ignition ON

Must be approx. 12 V

Yes

Printed circuit board faulty

-- Replace printed circuit board PRINTED CIRCUIT

Go to B

End

-- Switch ignition OFF-- Connect multimeter (Fluke 83 or equivalent) between terminals -3- (+) and -2- (-)-- Switch ignition ON

Must be 9.15-10.25 V

Yes

Printed circuit board faulty

Voltage stabilizer faulty

-- Replace printed circuit board PRINTED CIRCUIT

End