temp gauge intermittently not working?????
 

ok i gotta 2001 a4 quattro 2.8 30v....its got 77k on the clock and just recently my temperature guage started not workin intermittently...cant find a constant as to when it stops workin or starts again....but i did notice this, when the car is runnin it registers full cold but it does lift a lil tiny tiny bit from when the car is off and no power is goin to it......any ideas on what this can be? im hoping its not the cluster cuz i dont wanna have to go thru all that....please some1 out there tell me they had this problem and it was just the temp sensor or something?

RE: temp gauge intermittently not working?????
 

Most likly its a faulty coolant temp sensor. Very common failure. Dont think ive every see a problem with the cluster as far as the engine temp is concerned.

RE: temp gauge intermittently not working?????
 

but wouldnt that have thrown a code and a check engine light? ...

RE: temp gauge intermittently not working?????
 

Does the oil get up to temp? Just because the coolant temp is bouncing around or off doesn't mean it will throw a CEL.

RE: temp gauge intermittently not working?????
 

i have a 2001 1.8t it does the same thing drops then goes back to the middle then drops again. my friend has a 2000 a6 2.7t his does the same thing its np i think but i wanna know what could go wrong. its not the sensor because if it waas then it would never move from cold but it does then it drops for no reason after driving for a while

RE: temp gauge intermittently not working?????
 

this is happening to me, im thinking it cant be the temp sensor if u check the value your temperature sensor is reading (by using secret codes on climate control) it most likey will be the correct temperature, so if the climate control is showing correct temperature doesnt that mean the sensor is working fine?

RE: temp gauge intermittently not working?????
 

i have the same thing with no cel.sensor time.sp33 why are you making fun of other peoples audi's.

RE: temp gauge intermittently not working?????
 

air lock bleed the system properly

RE: temp gauge intermittently not working?????
 

there are seperate sensors. Engine coolant temp sensor and engine coolant temp sender. The sender is what sends the signal to the gauge. I beleave it is like this in the 01 I know in 98 it was. Anyway I will see if I can locate the diagram. Though I have run into bad gauges and you can replace just the gauge.

RE: temp gauge intermittently not working?????
 

Signal From Engine Coolant Temperature (ECT) Sensor -G2-, Checking

If a malfunction of the Engine Coolant Temperature (ECT) gauge is detected at the instrument cluster, check if the signal at the instrument cluster is OK.


Connect VAS5051 tester or VAG1551 scan tool. Refer to "Scan Tool Testing/Scan Tool Connecting and Initial Checks" under "Lighting and Horns"
Read Measuring Value Block. Refer to "Scan tool Testing/Measuring Value Blocks (Function 08)/Reading" under "Instrument Panel"
Select display group number 003.
If the Engine Coolant Temperature (ECT) appears on the VAG1551 scan tool display but not by the Engine Coolant Temperature (ECT) gauge, the instrument cluster is faulty and must be replaced.

If no Engine Coolant Temperature (ECT) is indicated on the VAG1551 scan tool display, the signal must be checked at multi-function connection at instrument cluster.


Remove instrument cluster.
Connect VAG1598 tester with VAG1598/25 adapter to the blue 32-pin connector.
Measure resistance (sensor resistance) between terminal 8 and 7 using VAG1526 multimeter.
Specified values:
Coolant temperature 90 °C : approx. 110 Ohms
Coolant temperature 120 °C : approx. 50 Ohms

If the specified values are not reached, the wire connection to Engine Coolant Temperature (ECT) -G2- must be checked.


Check wire connection according to wiring diagram.
If the wire connection is OK, Engine Coolant Temperature (ECT) -G2- must be replaced.

RE: temp gauge intermittently not working?????
 

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).

RE: temp gauge intermittently not working?????
 

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

RE: temp gauge intermittently not working?????
 

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

RE: temp gauge intermittently not working?????
 

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

RE: temp gauge intermittently not working?????
 

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

Temperature gauge inconsistent
 

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.