Passat Syncro Wagon V6-2.8L (ATQ) (2000)
Coolant Temperature Sensor/Switch (For Computer): Testing and Inspection
With Manufacturer's Scan Tool
Engine Coolant Temperature (ECT) sensor, checking
Special tools and equipment
-
V.A.G 1551 Scan Tool (or VAG 1552 mobile scan tool) with VAG 1551/3 cable
-
VAG 1598/31 test box
-
VAG 1526 multimeter or VAG 1715 multimeter
-
VAG 1594 connector test kit
-
Wiring diagram
Test condition
-
Engine must be cold.
Test sequence
-
Connect V.A.G 1551 scan tool (VAG 1552). Switch ignition on and select Engine Control Module (ECM) using address word 01. See: Powertrain
Management/Computers and Control Systems/Testing and Inspection/Reading and Clearing Diagnostic Trouble Codes/Scan Tool
Connecting/With Manufacturer's Scan Tool/Connecting VAG 1551 Scan Tool
Indicated on display
Rapid data transfer
HELP
Select function XX
-
Press buttons -0- and -8- to select "Read measuring value block" function 08. Press -Q- button to confirm input.
Indicated on display
Read Measuring Value Block
HELP
Input display group number XX
-
Press 0, 0 and 4 for function "display group number 4", and then press Q to exit from input mode.
Indicated on display (1 - 4 = display fields)
Read Measuring Value Block 4
->
1
2
3
4
-
Read coolant temperature value in display field 3.
Specification: approx. coolant temperature
If specified value is not obtained:
-
Continue testing according to following table:
Indication1)
Cause
approx. -48°C
Break or short to B+
approx. 143°C
Short circuit to Ground
1) If a temperature is indicated which differs greatly from ambient temperature of sensor, check sensor wires for contact resistance.
If the specified value is met:
-
Start engine, and let it idle.
The temperature should climb uniformly
NOTE:
-
The temperature climbs in increments of 1.0 °C.
-
If the engine shows problems in certain temperature ranges and if the temperature does not climb uniformly, the temperature signal is intermittent
and the sensor should be replaced.