Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Test sequence
- Connect vehicle diagnostic, testing and information system VAS 5051. See VAS 5051 VEHICLE DIAGNOSTIC, TESTING AND INFORMATION SYSTEM, CONNECTING AND SELECTING FUNCTIONS
. Select vehicle system "01 - Engine electronics" in selection. Engine must be run at idle.
Display on VAS 5051:
- Under -1- select diagnostic function "08 - Read measured value block".
Display on VAS 5051:
Courtesy of AUDI OF AMERICA, INC.
- Enter display group
- Enter "004" for "display group number 004" in zone -2- and confirm entry by pressing -Q- button.
- Check Engine Coolant Temperature (ECT) sensor -G62- in display zone -3-.
Display on VAS 5051:
| Display zones | ||||
|---|---|---|---|---|
| 1 | 2 | 3 | 4 | |
| Display group 004: Coolant temperature with engine at idle | ||||
| Display | xxxx rpm | xx.x V | xxx.x °C | xxx.x °C |
| Display | Engine speed | Battery voltage | Coolant temperature | Intake Air Temperature (IAT) |
| Range | -48.0...143.0 °C | |||
| Specified value | xxxx rpm | 12.0...15.0 volts | The temperature reading should increase evenly | from ambient temperature up to 110 °C |
If display zone 3 shows an implausible value:
- Disconnect Engine Coolant Temperature (ECT) sensor connector at -G2- / -G62- -arrow-.
- Connect multimeter between terminals C and D of sensor to measure resistance.
Range A shows resistance values for temperature range 0...50 °C and range B shows the values for temperature range 50...100 °C.
Sample readings:
- 30 °C corresponds to a resistance of 1500...2000Ω
- 80 °C corresponds to a resistance of 275..375Ω
- Replace Engine Coolant Temperature (ECT) sensor -G62-.
- Connect test box V.A.G 1598/31 to wiring harness for ECM; do not connect directly to the ECM. See ELECTRICAL TESTING USING VAG1598/31 TEST BOX .
- Check for open circuit, short to positive, or short to ground in following wiring connections:
If specified value is not obtained:
If specified value is obtained:
| Connector terminal | Test box V.A.G 1598/31 Socket |
|---|---|
| 3 | 108 |
| 4 (signal) | 93 |
- Test for short circuits between two wires.
- Repair any open/short circuit as necessary.
- Replace ECM. See ENGINE CONTROL MODULE (ECM) (WITHOUT METAL ANTI-THEFT HOUSING), REPLACING .
If no wiring problems are found:
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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.