Engine Coolant Temperature Sensor, Checking: Notes

Special tools and workshop equipment required 

• Multimeter VAG1526 or Multimeter VAG1715
• Connector test kit VAG1594
• Wiring diagram

Test Prerequisites 

• Fuses in E-box (plenum chamber, left) must be OK: Refer to SYSTEM WIRING DIAGRAM
  Fig 1: Identifying Fuse Holder

  Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.
• For vehicles with automatic transmission, selector lever must be in P.
• Battery voltage must be at least 11.5 volts.
• Ground (GND) connections between engine and chassis must be OK.
• Engine must be cold.

Function Test 

-- Connect diagnostic tester.

-- Switch ignition on.

-- Under address word 33, select "Diagnostic mode 1: Check measured values."

-- Select the measuring value "PID 05: Coolant temperature".

-- Check specified value of coolant temperature:

PID		Diagnostic text		Specified value:
05:		Coolant temperature		approx. coolant temperature

If specified value is not obtained:

-- End diagnosis and switch ignition off.

-- Control Module Wires, Checking, refer to CONTROL MODULE WIRES, CHECKING .

If specified value is obtained:

-- Start engine and let run at idle.

-- Check specified value of coolant temperature at idle:

PID		Diagnostic text		Specified value:
05:		Coolant temperature		Temperature value must rise evenly

-- Switch ignition off.