Engine temperature varies between 2 values - 2005 Audi A4

Temperature Blend Door Actuators The dual-zone EATC system uses 2 temperature blend door actuators to control 2 separate temperature blend doors. The temperature blend doors independently vary the LH side and RH side temperature settings, as desired. The temperature blend door actuators each contain a reversible electric motor and a potentiometer. The potentiometer circuit consists of a 5-volt reference signal connected to one end of a variable resistor, and a signal ground connected to the other. A signal return circuit is connected to a contact wiper, which is driven along the variable resistor by the actuator shaft. The signal returned to the EATC module from the contact wiper indicates the position of the temperature blend door. The EATC module drives the actuator motor in whichever direction is necessary to make the actuator contact wiper voltage agree with the expected EATC module contact wiper voltage value.

Manual or automatic climate control ?
Have you had the HVAC control panel checked for DTC'S - diagnostic trouble codes ?

Air Temperature Sensors
The air temperature sensors are a 2-wire negative temperature co-efficient thermistor. The vehicle uses the following air temperature sensors:
• Ambient Air Temperature Sensor
• Inside Air Temperature Sensor Assembly
• Upper Left Air Temperature Sensor
• Upper Right Air Temperature Sensor
• Lower Left Air Temperature Sensor
• Lower Right Air Temperature Sensor
A signal and a low-reference circuit enables the sensor to operate. As the air temperature surrounding the sensor increases, the sensor resistance decreases. The sensor signal voltage decreases as the resistance decreases. The sensor operates within a temperature range between -40°C (-40°F) to 101°C (215°F). The sensor signal varies between 0-5 volts.
The input of the duct air temperature sensors are different from the ambient and inside sensors. The HVAC control module converts the signal to a range between 0-255 counts. As the air temperature increases the count value will decrease.

• DTC B0174 Output Air Temperature Sensor (Upper Left) Circuit Range/Performance
• DTC B0179 Output Air Temperature Sensor 2 (Lower Left) Circuit Range/Performance
• B0414 is for the left air temperature actuator.
B0408 is for the left air temperature actuator.
DTC B0989 Output Air Temperature Lower Sensors Correlation
The HVAC control module monitors the upper left and upper right duct temperature sensors when the mode switch is in the VENT or BI-LEVEL positions. The HVAC control module monitors the lower left and lower right duct temperature sensors when the mode switch is in the DEFOG, FLOOR or FRONT DEFROST positions. The duct sensors are used to measure the temperature of the air exiting the ducts to help maintain a consistent cabin air temperature. These duct sensor inputs provide the HVAC control module a way to determine if the engine needs to be started to maintain a specific air temperature. If an upper duct sensor circuit failure is detected the HVAC module will not request an engine start to help cool the cabin. A lower duct sensor circuit failure will not prevent the engine from starting.
DTC B0990 Output Air Temperature Upper Sensors Correlation
Your best bet , take it to a qualified repair shop .

Auto transmission not changing down to 1st stage while in motion ? You mean not down shifting to first gear ! Which transmission does your cavalier have ?
Automatic Transaxle - 3T40 Automatic Transaxle - 4T40-E
Some of this may be over your head , if so I suggest you take it to a qualified repair shop .
Electrical/Garage Shift Tests
Perform this test before a hoist or road test in order to make sure that electronic control inputs are connected and operating. If you do not check the inputs before operating the transmission, you could misdiagnose a simple electrical condition as a major transmission condition.
Use the scan tool on the Hydra-Matic 4T40-E transmission for valuable information and accurate diagnosis.

1. Move the gear selector to Park (P) and set the parking brake.
2. Connect a scan tool to the DLC terminal.
3. Start the engine.
4. Connect power to the scan tool.
5. Verify that the following signals are present on the scan tool:
?€¢
Engine speed (RPM)



?€¢
Transmission input speed (Turbine)



?€¢
Transmission output speed



?€¢
Vehicle speed (miles/hour)



?€¢
A/B/C Range



?€¢
PRNDL select



?€¢
Desired PCS



?€¢
Actual PCS



?€¢
PCS duty cycle



?€¢
Brake switch



?€¢
Engine coolant temperature (Coolant)



?€¢
Transmission fluid temperature (Trans Temp)



?€¢
Throttle angle (TPS)



?€¢
System volts


6. Monitor the BRAKE SWITCH signal while tapping the brake pedal with your foot. The brake switch signal should be:
Released -- when the brake pedal is released
Applied -- when the brake pedal is depressed

7. Monitor the PRNDL SELECT signal and move the gear selector through all the ranges.
Verify that the PRNDL SELECT value matches the gear range indicated on the instrument panel or console.
The gear selections should be immediate and not harsh.

8. Move the gear selector to Neutral and monitor the throttle angle signal while increasing and decreasing engine RPM with the accelerator pedal.

The throttle angle should increase with engine RPM.
Functional Test

Step

Action

Value(s)

Yes

No

1

Perform the Transmission Fluid Check .

Is the fluid level correct?
--
Go to Step 2
--

2

Check for PCM trouble codes, both current and history.

Are PCM trouble codes present?
--
Go to Diagnostic Trouble Code Identification
Go to Step 3

3

1. Perform the Electrical/Garage Shift Tests .
2. Perform the Road Test .

Was the condition duplicated?
--
Go to Step 4
Go to Step 12

4

Is a harsh or soft shift condition present
--
Go to Step 7
Go to Step 5

5

Is the vehicle's performance poor?
--
Go to Torque Converter Evaluation section of Torque Converter Clutch Diagnosis
Go to Step 6

6

Is the engagement into Drive or Reverse delayed or missing?
--
Go to Step 7
Go to Step 9

7

Perform the Line Pressure Check .

Is the line pressure correct?
--
Go to Step 8
Refer to Symptom Diagnosis Charts

8

Inspect the transmission wire harness connectors and the transmission range switch.

Was the problem found and corrected?
--
System OK
Refer to Symptom Diagnosis Charts

9

Is vibration or noise a problem?
--
Refer to Vibration Test Procedure of Torque Converter Clutch Diagnosis
Go to Step 10

10

Is the fluid leaking?
--
Refer to Fluid Leak Diagnosis and Repair
Go to Step 11

11

Are other transmission conditions present?
--
Refer to Symptom Diagnosis Charts
Go to Step 12

12

The condition is intermittent.

Re-examine the complaint.
--
Exit Table
--
No Engine Braking; Manual First - First Gear

No Engine Braking; Manual First -- First Gear
Checks

Causes

Coast Clutch

No apply (Refer to No Engine Braking; All Manual Ranges )

Lo and Reverse Servo

No apply (Refer to No Reverse or Slips in Reverse )

Pressure Switch Assembly (13)

Leaking or inoperative

#1 Checkball

Missing
Tech 1 Data Value Examples
Table 1:
Engine 1
Table 2:
Engine 2
If you have completed the On-Board Diagnostic (OBD) system check, if the diagnostics are functioning properly and if no DTCs display, you may use the Typical Scan Values in the table below for comparison within the appropriate transmission. These typical values are an average of display values recorded from normally operating vehicles. They represent the display from a normally functioning system.
You should never use a scan tool that displays faulty data. The problem should be reported to the manufacturer. The use of a faulty scan tool can result in misdiagnosis and the unnecessary replacement of parts.
Only the parameters listed below are used in this manual for diagnosing. If a scan tool displays other parameters, the values are not recommended by General Motors for use in diagnosis.
Scan tests are performed under the following driving conditions:
?€¢
Idle

?€¢
Upper radiator hose is hot

?€¢
Closed throttle

?€¢
Park or Neutral

?€¢
Closed Loop

?€¢
Accelerator OFF

?€¢
Brake not applied

Parameters that are marked with an (*) asterist are also valid in the Engine 2 list.

Engine 1
Tech 1 Parameter

Units Displayed

Typical Scan Values
*Engine Speed
RPM
100 RPM from the desired RPM
*Desired Idle
RPM
Varies
*ECT
C?°(F?°)
85?°-115?°C (Varies with coolant temperature)
*MAP
kPa, V
1-3V (Varies with vacuum and Baro pressure)
*Baro
kPa, V
3-5V (Varies with altitude and Baro pressure)
*TP Sensor
V
.200-.900V
*TP Angle
%
0%
*Ignition Volts
V
12.0-15.0V
Loop Status
Open/Closed
Closed
TCC Brake Switch
ON/OFF
OFF
Engine Run Time
Hr:Min:Sec
Varies since start up
# of Current DTCs
#
0

Engine 2
Tech 1 Parameter

Units Displayed

Typical Scan Values
A/C Request
Yes/No
No
Cruise Engaged
Yes/No
No
TCC Enabled
ON/OFF
OFF
TCC Slip Speed
RPM
Varies
Trans. OSS
RPM
0
Trans. Range
Invalid/Low/Drive2/Drive3/ Reverse/Park/Neutral
Park/Neutral
km/h (mph)
km/h (mph)
0
?© 2016 General Motors Corporation. All rights reserved

after 1 minute, it comes down? right?
wow no year stated, are you kidding? wiki land cruiser. ouch. huge types and type not stated either nor engine options ,nor country.?????????????????????????????????????????
Strike 4, ouch.
the dash gauge, engine temperature of coolant?
are you saying the coolant temp. varies, hot?
if yes?
1: bad thermostat.
2: if in Klondike or like zone, it can be normal so block rad with cardboard. no location of car stated, to im , gobsmacked, dumb.

see the wiki, see this wild car. all the variants, find yours and state yours.

http://en.wikipedia.org/wiki/Toyota_Land_Cruiser

i never, ever read, dash gauges.(besides a glance, then)
i use real hand gauges,

in details,. it varies from where to where.???????
180F to 150?
250 to 180F?
30F to 100F? what?
where does it vary, , see why a real guage works wonders
this works magic, (best tool in shop) lots of uses.
http://www.harborfreight.com/infrared-thermometer-93984.html

Just some suggestions.
Clean the end of your key and get an earbud and metho/alchol and clean the keyhole sensor.
Change the battery in your key.
Check the charge level on the battery. Recharge.
Check alternator charging.
climatecontrol diagnostic menu

To enter mode press "REST" for more than 5 seconds. Use the left & right Auto buttons to scroll.
standing
value code description
15 1 Inside Temperature
11 2 Outside Temperature
11 3 Left Heater Core Temperature
10 4 Right Heater Core Temperature
10 5 Evaporator Temperature
11 6 Engine Coolant Temperature
3 7 Refrigerant Pressure: displayed as 1.xx bar where xx is in the display
10 8 Refrigerant Temperature
0 9 Not Used
1.2 10 Blower Control Voltage: 6.0V
11 Emission Sensor: 2.4V
12 Sun Sensor: 4.1V
0 20 Control Current for Auxiliary Fan: 3.2mA (Is this value too low?)
0 21 Engine RPM: 44 => 4,400rpm
0 22 Vehicle Speed
0 23 Terminal 58d: 32 or 32% of Full Battery Charge
12.0 24 Battery Voltage: 13.3V
8 40 Software Status: 164
5 41 Hardware Status: 85
216 42 Variant Code 1st numerical value
14 43 Variant Code 2nd numerical value

50 Not assigned
51 Not assigned
52 Not assignd
60 Roof OPE/CLO
61 Left side air outlet, knurled wheel potentiometer Volts
62 Vacuum actuator 46, feedback potentiometer Volts
63 Center outlet, knurled wheel potentiometer Volts
64 Vacuum actuator 47, feedback potentiometer Volts
65 Right side air outlet, knurled wheel potentiometer Volts
66 Vacuum actuator 48, feedback potentiometer Volts

Item 63 is the input signal from the thumbwheel controlfor the center vent, and 64 is the feedback signal to the controller giving it the position of the vent flap. As you move the thumbwheel these values should continously vary from a minimum of roughly .7 to 4.5.

The ECT (Engine Coolant Temperature) sensor is a thermal variable resistor (also known as a "thermistor"). The ECT delivers a signal to the THW terminal of the Engine Control Module (ECM) which varies with engine coolant temperature. The ECM uses this signal to control the fuel injection system, the overdrive operation on vehicles equipped with electronically controlled overdrive transmissions, spark timing control, idle speed control, fuel pressure control system (if equipped), heated oxygen sensor system (if equipped) and EGR systen (if equipped)

The fuel injection has an engine temperature sensor that is supposed to make the mixture very rich when cold, but then leaner as it warms up. If the thermal resistor is burned out, then it will have too much resistance all the time, and the engine will be flooded out. Use an ohmmeter to measure the temperature sensor resistance. I don't remember the exact values, but bad ones often times go 0 or infinite. And you should see it vary with temperature.

According to Autozone.com:

Because ECT (engine coolant temperature) sensor procedures vary depending upon their location, first locate the part. You may need to partially drain the engine coolant to prevent coolant spillage.

• Disconnect the negative battery cable.
• Unplug the ECT.
• Then, unscrew it.
• Reverse the removal procedures to install the new part.
• Connect the negative battery cable to the battery.

Related Parts:



Cooling Fan Switch
Content for class "spacer" Goes Here

Engine Temperature Sensor
Content for class "spacer" Goes Here

Temperature Switch
Content for class "spacer" Goes Here

---
Coolant Temperature Sensor

Fig. Remove the coolant temperature sensor
The coolant temperature gauge sensor is a temperature-variable resistor, or thermistor. As coolant temperature increases, the resistance of the sensor decreases or decreases, depending on the type of sensor.
A1 and A2 platforms use a different type of circuit that A3 vehicles. On A1 and A2 vehicles, the circuit is a "resistance to ground" type. A3 vehicles use a "variable voltage" type, where a voltage is supplied to the sensor. Because of the circuitry design on A3 vehicles, testing of the coolant temperature gauge is limited.
The engine coolant temperature gauge uses a heat sensitive sending unit to transmit an electrical signal to the gauge. The sending unit is a heat sensitive variable resistor that is located on or near to the cylinder head and threads into an engine coolant passage. The sensors are a Negative Temperature Coefficient (NTC) type. As the temperature increases, the electrical resistance of the sensor decreases. As the coolant temperature changes, so does the resistance of the sensor. The gauge is calibrated within the operating range of the sensor and interprets the resistance value to display the coolant temperature.
Beginning with model year 1994, the engine coolant gauge and the Engine Control Module (ECM) temperature sensors were combined into one sensor with 4 terminals. The basic operation remains the same in that their resistance decreases as the coolant temperature increases, however the actual resistance values of the 2 sensor circuits are different. The electrical connector of the 4-wire terminal sensor ( 1 and 2 ) is keyed to prevent improper connection of the sensor's electrical circuit.

Fig. Beginning with model year 1994, the Engine Coolant Temperature Sensors combined the sensors for the ECM and the gauge into one sensor-1997 2.8L V6 sensor shown

Fig. The electrical connector for the combined temperature sensors is keyed to avoid improperly connecting the sensor's wiring-1997 2.8L V6 connector shown

A educated guess I would have to say there is a problem with HVAC control module ! electronics you know ! But that's not the way to do things ! There could be codes stored in the module. The Chevy dealer my have a reflash bulletin for this problem . Then can reflash , reprogram the control module ! The first place to start is checking for codes in the HVAC module.
The HVAC control module is a class 2 device that interfaces between the operator and the HVAC system to maintain air temperature and distribution settings. The battery positive voltage circuit provides power that the control module uses for keep alive memory (KAM). If the battery positive voltage circuit loses power, all HVAC DTCs and settings will be erased from KAM. The body control module (BCM), which is the vehicle mode master, provides a device on signal.
Air Temperature Sensors The air temperature sensors are a 2-wire negative temperature co-efficient thermistor. The vehicle uses the following air temperature sensors:
?€¢
Ambient Air Temperature Sensor

?€¢
Inside Air Temperature Sensor Assembly

?€¢
Inside Air Temperature Sensor Assembly-Auxiliary

?€¢
Upper Left Air Temperature Sensor

?€¢
Upper Right Air Temperature Sensor

?€¢
Lower Left Air Temperature Sensor

?€¢
Lower Right Air Temperature Sensor

?€¢
Upper Air Temperature Sensor-Auxiliary

?€¢
Lower Air Temperature Sensor-Auxiliary
A signal and low reference circuit enables the sensor to operate. As the air temperature surrounding the sensor increases, the sensor resistance decreases. The sensor signal voltage decreases as the resistance decreases. The sensor operates within a temperature range between -40?° to +101?°C (-40?° to +215?°F). The sensor signal varies between 0-5 volts.
The input of the duct air temperature sensors are different from the ambient and inside air temperature sensors. The HVAC control module converts the signal to a range between 0-255 counts. As the air temperature increases the count value will decrease.
If the HVAC control module or auxiliary HVAC control module detects a malfunctioning sensor, then the control module software will use a defaulted air temperature value. The default value for the ambient and inside air temperature sensors will be displayed on the scan tool. The default value for the duct air temperature sensors will not be displayed on the scan tool. The scan tool parameter for the duct air temperature sensors are the actual state of the signal circuit. The default action ensures that the HVAC system can adjust the inside air temperature near the desired temperature until the condition is corrected.
The ambient air temperature sensor mounts underhood and can be affected by city traffic, by idling, and by restarting a hot engine. Therefore, the HVAC control module filters the value of the ambient air temperature sensor for temperature display. The ambient air temperature value is updated under the following conditions: Or you can just buy a new control module an hope that it fixes it. $89.00 at www.partsgeek.com

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ENGINE COOLANT TEMPERATURE SENDER 1. Using an ohmmeter, measure the resistance between terminal 2 and ground. 2. If the resistance value is not as shown below, replace the temperature sender. Temperature (°C) 60 85 110 125 Resistance (Ω) 119.4 48.9 25 15.8