Engine Coolant Temperature (ECT) Sensor -G2-, checking

If the coolant temperature gauge is malfunctioning, check whether the coolant temperature sensor signal is being received by the instrument cluster.

• Connect scan tool. Refer to VAG 1551/1552 Scan Tool (ST), VAS 5051 Vehicle Diagnostic Testing and Information System or VAS 5052 Vehicle Diagnostic and Service System, connecting and selecting functions  .
• Select "Read Measuring Value Block" function 08. Refer to Read Measuring Value Block (function 08)  .
• Select Display Group 003.

If coolant temperature is indicated on scan tool, the instrument cluster is malfunctioning and must be replaced.

• Removing instrument cluster. Refer to Instrument cluster, removing and installing  .

If coolant temperature is not indicated on scan tool, test the signal at the multi-pin connector on the instrument cluster.

• Removing instrument cluster. Refer to Instrument cluster, removing and installing  .
• Connect test box VAG 1598 to the blue 32-pin connector using adapter VAG 1598/25.
• Use multimeter to measure resistance between contacts 8 and 9 (load Ground).

Specifications:

• Coolant temperature 90 ° C: approx. 110 Ohm
• Coolant temperature 120 ° C: approx. 50 Ohm

• If measured values do not match specifications, test wiring between instrument cluster and coolant temperature sender using wiring diagram.

Refer to Electrical Wiring Diagrams

• If there are no open circuits or short circuits, replace the coolant temperature sender.