Engine Coolant Temperature Sensor On Radiator, Checking

Special tools and workshop equipment required 

• Multimeter.
• Wiring diagram.

Test requirements

• The Motronic Engine Control Module (ECM) - J220- fuses OK.
  Fig 1: Identifying Fuses On E-Box In Engine Compartment, Left Side

  Courtesy of AUDI OF AMERICA, LLC
• Battery voltage at least 12.5 volts.
• All electrical consumers such as, lights and rear window defroster, switched off.
• Vehicles with automatic transmission, shift selector lever into position "P" or "N".
• A/C switched off.
• Ground (GND) connections between engine/transmission/chassis OK.
• Ignition switched off.
• Engine cold.

Test procedure

-- Perform a preliminary check to verify the customers complaint. Refer to GENERAL DIAGNOSIS .

Start diagnosis

Checking internal resistance

-- Disconnect the Engine Coolant Temperature (ECT) Sensor (on Radiator) -G83- electrical harness connector -1-.

-- Using a multimeter, check the Engine Coolant Temperature (ECT) Sensor (on Radiator) -G83- terminals 1 to 2 for resistance.

Use the chart below for the specified values:

• Area A: Resistance values 0 to 50° C.
• Area B: Resistance values 50 to 100° C.

Specified values:

• Range A, 30° C equals a resistance of 1.5 to 2.0 kΩ
• Range B, 80° C equals a resistance of 275 to 375Ω

If any of the specified values was not obtained:

-- Replace the Engine Coolant Temperature (ECT) Sensor (on Radiator) -G83-.

If any of the specified values was obtained:

Checking wiring

If the manufacturers test box is being used. Perform the following step.

-- Install the test box. Refer to Repair information.

If the manufacturers test box is not being used. Perform the following step.

-- Remove the Motronic Engine Control Module (ECM) -J220-. Refer to MOTRONIC ENGINE CONTROL MODULE, REPLACING .

-- Using a Multimeter --, check the Engine Coolant Temperature (ECT) Sensor (on Radiator) -G83- electrical harness connector terminals to the Motronic Engine Control Module (ECM) -J220- electrical harness connector T121 terminals for an open circuit according to the wiring diagram.

Engine Coolant Temperature (ECT) Sensor (on Radiator) -G83- electrical harness connector terminals	Motronic Engine Control Module (ECM) -J220- electrical connector 121 terminals or test box socket
1	17
2	50

Specified value: 1.5 Ω Max.

If the specification was not obtained:

-- Check the wiring for a short circuit to each other, Battery (+), and Ground (GND).

-- Check the electrical harness connector for damage, corrosion, lose or broken terminals.

-- If necessary, repair the faulty wiring connection.

If no malfunction is detected in the wiring:

-- Replace the Motronic Engine Control Module (ECM) -J220-. Refer to MOTRONIC ENGINE CONTROL MODULE, REPLACING .

Final procedures

After repair work, the following work steps must be performed in the following sequence:

1. Check the DTC memory. Refer to DIAGNOSTIC MODE 03 - READ DTC MEMORY .
2. If necessary, erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
3. If the DTC memory was erased, generate readiness code. Refer to READINESS CODE .

-- End of diagnosis.