With Manufacturer's Scan Tool
Engine Coolant Temperature (ECT) Sensor -G62-, Checking
Special tools
- VAG 1551/1552 Scan Tool or vehicle system tester VAG 1552 using VAG 1551/3 Adapter cable
- VAG 1598/22 Test Box (MY 1999)
- VAG 1598/31 Test Box (from MY 2000)
- Fluke 83 multimeter
- VW 1594 Adapter kit
- Wiring diagram
Test sequence
- Connect VAG 1551/1552 Scan Tool.
- Start engine and let idle.
- Press 0 and 1 buttons to select Address word 01: "Engine electronics"
Display will appear as shown (example only)
03890601 8M 1.9l R4 EDC 00AG 1813 ->
Coding 0001 WSC XXXXX
- Press -> button.
Display will appear as shown
Rapid data transfer HELP
Select function XX
- Press 0 and 8 buttons to select Function 08: "Read measuring value block".
Display will appear as shown
Read measuring value block HELP
Input Display group number XXX
- Press 0, 0 and 7 buttons to select "Display group 7".
Read measuring value block 7
15.4 °C 15.9 °C 16.7 °C
Display will appear as shown
- Observe Engine Coolant Temperature value in Display zone 4.
- Temperature value must Increase uniformly without interruption.
NOTE: In the event of malfunctions, Fuel temperature is displayed as a substitute.
If an unrealistic value appears in Display zone 4 or Fuel temperature is displayed as a substitute
- Check Engine Coolant Temperature (ECT) Sensor -G62- and wiring to sensor as follows
- Press -> button.
Display will appear as shown
Read measuring value block HELP
Input Display group number XXX
- Press 0 and 6 buttons to select Function 06: "End output".
- Press Q button to enter input.
- Switch OFF ignition.
- Disconnect -G62- harness connector (arrow).
- Measure resistance between sensor terminals 1 + 3.
Specification see diagram
Scale A shows resistance values for temperature range 0 to 50 °C and scale B the values for temperature range 50 to 100 °C.
Examples:
- 30 °C corresponds to a resistance from 1500 to 2000 Ohms
- 80 °C corresponds to a resistance from 275 to 375 Ohms
If specification not obtained
- Replace Engine Coolant Temperature (ECT) Sensor -G62-.
- Display the Readiness code. Monitors, Trips, Drive Cycles and Readiness Codes
If DTC memory was erased
- Set the Readiness code. Monitors, Trips, Drive Cycles and Readiness Codes
If specification obtained
- Connect VAG 1598/22 (or 1598/31) Test Box to ECM wiring harness.
- Check wiring for open circuit between Test Box and 4-pin harness connector using Wiring diagram.
Up to MY 1999
- Terminal 1 + socket 70
- Terminal 3 + socket 54
From MY 2000
- Terminal 3 + socket 112
- Terminal 4 + socket 104
Wire resistance: 1.5 Ohms maximum
- Check wires for shorting to: one another, Ground and Battery +
Specification: Infinity Ohms
If wiring OK
- Replace Engine Control Module -J248-
- Erase DTC memory (Disconnecting the Engine Coolant Temperature sensor generates a DTC). Clearing Diagnostic Trouble Codes