Engine Coolant Temperature (ECT) gauge -G3-, checking

If the engine coolant temperature gauge in the instrument cluster does not indicate a reading, first check whether the signal is received by the instrument cluster.

Connect VAG1551/VAG1552 Scan Tool (ST) and press buttons -1- and -7- to insert "Instrument Cluster" address word 17 (with ignition switched on). See INSTRUMENT CLUSTER .
Indicated on display

Fig 1: Scan Tool Display - Engine Coolant Temperature Gauge (1 Of 8) (Up To M.Y. 1999)
- Press -Q- button to confirm input.
Indicated on display (after approximately 5 seconds)

Fig 2: Scan Tool Display - Engine Coolant Temperature Gauge (2 Of 8) (Up To M.Y. 1999)
- Press -> button.
Indicated on display

Fig 3: Scan Tool Display - Engine Coolant Temperature Gauge (3 Of 8) (Up To M.Y. 1999)
- Press buttons -0- and -8- to select "Read Measuring Value Block" function 08.
Indicated on display

Fig 4: Scan Tool Display - Engine Coolant Temperature Gauge (4 Of 8) (Up To M.Y. 1999)
- Press -Q- button to confirm input.
Indicated on display

Fig 5: Scan Tool Display - Engine Coolant Temperature Gauge (5 Of 8) (Up To M.Y. 1999)
- Press buttons -0-, -0- and -3- to input display group number 003, and press -Q- button to confirm input.
Indicated on display (1-4 = display fields)

Fig 6: Scan Tool Display - Engine Coolant Temperature Gauge (6 Of 8) (Up To M.Y. 1999)

If the engine coolant temperature is displayed in display field 1 on the scan tool, the instrument cluster is faulty and must be replaced. Removing instrument cluster. See INSTRUMENT CLUSTER, REMOVING AND INSTALLING .

If the engine coolant temperature is not displayed in display field 1 on the scan tool:
- Check the signal to the multi-pin connector for the instrument cluster.
- Press -> button.
Indicated on display

Fig 7: Scan Tool Display - Engine Coolant Temperature Gauge (7 Of 8) (Up To M.Y. 1999)
- Press buttons -0- and -6- to select "End Output" function 06.
Indicated on display

Fig 8: Scan Tool Display - Engine Coolant Temperature Gauge (8 Of 8) (Up To M.Y. 1999)
- Press -Q- button to confirm input.
- Connect VAG1598 test box to blue 32-pin connector using adapter VAG1598/25.
- Using multimeter US1119 (Fluke 83 or equivalent), measure resistance between terminals 8 and 7, (signal Ground).
Specifications:
- Engine coolant temperature 60 °C (140 °F): approx. 259 ohm
- Engine coolant temperature 90 °C (194 °F): approx. 107 ohm
- Engine coolant temperature 120 °C (248 °F): approx. 40 ohm
If values are not as specified:
- Checking wiring.
- Replace sensor.