Engine Coolant Temperature (ECT) sensor -G62-, checking
Special tools and equipment
- VAG1526 A
- VAG1594 A
- VAG1598/31
- VAS5051 with VAS5051/1
Installation location. Refer to Component locations, overview
Test requirements
- Engine cold
Test sequence
- Connect testing and information system VAS5051. Refer to «Vehicle diagnostic, testing and information system VAS5051, connecting and select functions»(/audi/a4/b6-2000-2006/remont/cooling-fan/#30l-6-cyl-5v-engine-controls-fuel-injection-ignition-engine-codes-avk-bgn__vehicle-diagnostic-testing-and-information-system) and select vehicle system "01 - Engine electronics" in selection. Engine must be running at idling speed.
Display on VAS5051
- Under -1- select diagnostic function "08 - Read measured value block".
Display on VAS5051
1 - Enter display group
- Enter "004" for "display group number 004" in zone -2- and confirm entry by pressing -Q- button.
Display on VAS5051
- Check indication in display field -3-.
| Display zones | ||||
|---|---|---|---|---|
| 1 | 2 | 3 | 4 | |
| Display group 004: Coolant temperature with engine idling | ||||
| Display | Xxxx RPM | Xx.x V | Xxx.x°C | Xxx.x°C |
| Display | Engine speed | Battery voltage | Coolant temperature | Intake air temperature |
| Range | 48.0 to 143.0°C | |||
| Specif. value | Xxxx RPM | 12.0 to 15.0 V | The temperature reading should increase evenly | From ambient temperature up to 110°C |
If display zone 3 shows an implausible value
Scheme 583
- Disconnect connector -2- at Engine Coolant Temperature (ECT) sensor -G2-/-G62-.
Scheme 584
- Connect multimeter between terminals C and D of sensor to measure resistance.
Range A shows resistance values for temperature range 0 to 50°C and range B shows the values for temperature range 50 to 100°C.
Scheme 585
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 attained
- Replace engine coolant temperature sensor.
If specified value is attained
- Connect test box VAG1598/31 to wiring harness for engine control module; do not connect engine control module. Refer to «Wiring and component check with test box VAG 1598/31»(/audi/a4/b6-2000-2006/remont/cooling-fan/#30l-6-cyl-5v-engine-controls-fuel-injection-ignition-engine-codes-avk-bgn__wiring-and-component-check-with-test) .
Scheme 586
- Check for open circuit and short to positive or ground in following wiring connections
| Connector Terminal | Test box VAG1598/31 Socket |
|---|---|
| 3 | 108 |
| 4 (signal) | 93 |
- Test for short circuits between two wires.
- Repair any open/short circuit as necessary.
If no wiring malfunction is detected
- Replace engine control module. Refer to «Engine Control Module (ECM) (without metal anti-theft housing), replacing»(/audi/a4/b6-2000-2006/remont/cooling-fan/#30l-6-cyl-5v-engine-controls-fuel-injection-ignition-engine-codes-avk-bgn__engine-control-module-ecm-without-metal) .