Engine Coolant Temperature (ECT) Sensor -G62-, Checking

Special Tools and Equipment









VAG1526A
VAG1594A
VAG1598/31
VAS5051 with VAG5051/1
Test requirement :


Engine cold
Test sequence


Connect VAS5051 tester and select vehicle system "01 - Engine electronics". Engine must run at idle for this. Refer to "Scan Tool Testing/Scan Tool Connecting and Initial Checks/VAS 5051 Tester, Connecting and Selecting Functions" See: Powertrain Management\Computers and Control Systems\Testing and Inspection






Display on VAS5051:


Select diagnostic function "08 - Read Measuring Value Block" in selection -1-.






Display on VAS5051:


1 - Enter display group Max. input value = 255

Select function "004" in button field -2- for "display group number 004" and press Q button to confirm input.






Display on VAS5051:


Check coolant temperature sensor in display field -3-.
Display Group 004








Press "08 - Read Measuring Value Block" to end function <- button.
If display field 3 does not have a realistic indication:


Disconnect connector at coolant temperature sensor.








Connect multimeter between terminal C and D of sensor for resistance measurement.
Range A shows the resistance values for the temperature range from 0-50 °C , and range B shows the values for the temperature range from 50-100 °C .







Read-out examples:


30 °C corresponds to a resistance of 1500 to 2000 ohms W
80 °C corresponds to a resistance of 275 to 375 ohms
If specified value is not obtained:


Replace coolant temperature sensor.
If specified value is obtained:


Connect VAG1598/31 test box at wiring harness to Engine Control Module (ECM), do not connect ECM. Refer to "Scan Tool Testing/Wire and Component Testing Using VAG1598/31 Test Box" See: Powertrain Management\Computers and Control Systems\Testing and Inspection








Check the following wire connections for open circuit and short circuit to Ground (GND) and B+:








Check both wires to each other for short circuit.
Repair open circuit or short circuit if necessary.
If no malfunctions are found in wires:


Replace Engine Control Module (ECM).

 

Maybe those will help there are both. Must get to work now.

 

excellent now i gotta dig up vag from under my bed somewhere

 

ok yeah the oil temp goes up....and rnbguy thanx for all the info but i dont have the scan tool lol

 

Hi guys,

I have a 2004, 1.9tdi 130, has the same issue, while driving the temperature falls to zero and then back up to normal, i was assuming it was a fault with the temp sensor, but not sure as its intermittent.

Anything you can suggest for all us users who don't have the diagnostic tools?

Cheers

 

2004 Audi TT quattro--twin turbo. 166,000 miles. Twice recently, the gauge would not come up to middle. First time, it was on first indent. Then, it worked fine again. Today. same issue except now only goes to second indent. Ideas? Bad gauge, sensor, or is the engine running too cold? Thank you.