Engine Coolant Temperature (ECT) sensor -G62-, checking
Special tools and workshop equipment required
- V.A.G 1526 A Multimeter
- V.A.G 1594 A Connector test kit
- V.A.G 1598/31 Test box
- VAS 5051 Vehicle diagnostic, testing and vehicle information system with VAS 5051/1 Adapter
Component location --> Component locations, overview
Requirements
- Engine cold
Work sequence
- Connect vehicle diagnostic, testing and information system VAS 5051. Refer to «VAS 5051 vehicle diagnostic, testing and information system, connecting and selecting functions»(/audi/a4/b7-2004-2009/remont/blowers-superchargers-turbochargers/#18l-4-cyl-5v-turbo-engine-controls-fuel-injection-ignition-engine-codes-amb__vas-5051-vehicle-diagnostic-testing-and) and 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
1 - Enter display group
- Enter "004" for "display group number 004" in zone -2- and confirm entry by pressing -Q- button.
Display on VAS 5051
- Check Engine Coolant Temperature (ECT) sensor -G62- in display zone -3-.
| 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 to 15.0 volts | The temperature reading should increase evenly | From ambient temperature up to 110 ° C |
If display zone 3 shows an implausible value
Scheme 803
- Disconnect Engine Coolant Temperature (ECT) sensor connector at -G2-/-G62- (arrow).
Scheme 804
- 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.
Scheme 805
Sample readings
- 30 ° C corresponds to a resistance of 1500 to 2000 ohms
- 80 ° C corresponds to a resistance of 275 to 375 ohms
If specified value is not obtained
- Replace Engine Coolant Temperature (ECT) sensor -G62-.
If specified value is obtained
- Connect test box V.A.G 1598/31 to wiring harness for ECM; do not connect directly to ECM. Refer to «Electrical testing using VAG1598/31 test box»(/audi/a4/b7-2004-2009/remont/blowers-superchargers-turbochargers/#18l-4-cyl-5v-turbo-engine-controls-fuel-injection-ignition-engine-codes-amb__electrical-testing-using-vag159831-test-box) .
Scheme 806
- Check for open circuit, short to positive, or short to ground in following wiring connections
| 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.
If no wiring problems are found
- Replace ECM. Refer to «Engine Control Module (ECM) (without metal anti-theft housing), replacing»(/audi/a4/b7-2004-2009/remont/blowers-superchargers-turbochargers/#18l-4-cyl-5v-turbo-engine-controls-fuel-injection-ignition-engine-codes-amb__engine-control-module-ecm-without-metal) .