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For those aggravated by the ICE running during short trips in the winter months, there are a few mods for preventing or delaying ERDTT. Note that employing some of these mods may or may not cause warranty issues if there is a problem later on.
The location of the air temperature sensor that controls ERDTT, how it operates and the theory that adding a 1/8W 39K Ohm resistor could cause the car to see a higher temperature was originally posted on GM-Volt by our own WOT and Tboult. Subsequently others, including Frank Weber (Volt chief engineer, now BMW i3), used this information to create a mod that prevented ERDTT.
1.Resistor Method
This relies on tricking the air temp sensor into seeing a higher temp by adding a 1/8W 39K Ohm resistor between the two sensor pins and therefore prevent ERDTT.
See https://gm-volt.com/forum/showthread....98#post1140098 and
See https://gm-volt.com/forum/showthread....86#post1140786
Frank Weber (Volt chief engineer, now BMW i3) also posted his personal mod along these lines. http://roulezelectrique.com/recalibr...re-de-la-volt/ (use Google Chrome browser for auto-translation) The method does appear to work.
Variation 1: Switched Resistor Under Hood
Rather than attaching the resistor directly to the sensor, attach it via a switch under the hood
See https://gm-volt.com/forum/showthread....33#post1506433
New version was here (seems to be gone now): http://www.ebay.ca/itm/Sonde-tempera.../281246258931?
New link: http://www.ebay.com/sch/i.html?_odk...Volt.TRS0&_nkw=ERDTT+Volt&_sacat=0&rmvSB=true
Also see https://gm-volt.com/forum/showthrea...tic-ERDTT-disabling-Add-on-modules-availables...
Variation 2: Switched Resistor in Cabin
You don't need to access/replace/modify the sensor itself. Add the resistor with a switch in the passenger compartment by locating the appropriate wire pair. The air temp sensor is a two-wire circuit that runs from the bumper-mounted air sensor pins, through the right side underhood area, then through the front bulkhead pass-through to the HPCM2 (Hybrid Hybrid Powertrain Control Module 2 X1) module under the front passenger seat. The circuit could be accessed and modified with a resistor anywhere between those end points.
Pin Size Color Circuit Function
26 0.35 L-BU/GY 636 Outside Ambient Air Temperature Sensor Signal
40 0.35 BK/L-BU 61 Outside Ambient Temperature Sensor Low Reference
LugNuts Implementation thread: https://gm-volt.com/forum/showthread.php?328361-All-I-want-for-Christmas-is-no-ERDTT
Resistance testing discussion by WOT and TBoult here: https://gm-volt.com/forum/showthread....-..-quot/page3
2. Covered Sensor Method
The other method is to simply slow the temperature sensor by blocking it from direct wind.
Cover the sensor or the air intake grills with 1/2 " foam pipe insulation or cardboard to keep it out of the direct wind. This will delay ERDTT but will not stop it. One who tried closing the air space between the intake grills with the pipe insulation reports: 25-30% reduction in gasoline consumption in ERDTT mode ( 2,25 l/100km to 1,75 l/100km ). because the ICE simply cycles less frequently. Testing was done on the same route every day, 130 km (81miles) per day. “No check engines, nada problems.”
See https://gm-volt.com/forum/showthread....42#post1143442
and https://gm-volt.com/forum/showthread....26#post1191426
and https://gm-volt.com/forum/showthread....50#post1514650
Reference Posts:
https://gm-volt.com/forum/showthread....n-Kit-Aero-Mod.
https://gm-volt.com/forum/showthread....42#post1143442
https://gm-volt.com/forum/showthread....-winter-Anyone
https://gm-volt.com/forum/showthread....86#post1140786
https://gm-volt.com/forum/showthread....98#post1145498
http://roulezelectrique.com/recalibr...re-de-la-volt/
https://gm-volt.com/forum/showthread....-..-quot/page3
The location of the air temperature sensor that controls ERDTT, how it operates and the theory that adding a 1/8W 39K Ohm resistor could cause the car to see a higher temperature was originally posted on GM-Volt by our own WOT and Tboult. Subsequently others, including Frank Weber (Volt chief engineer, now BMW i3), used this information to create a mod that prevented ERDTT.
1.Resistor Method
This relies on tricking the air temp sensor into seeing a higher temp by adding a 1/8W 39K Ohm resistor between the two sensor pins and therefore prevent ERDTT.

See https://gm-volt.com/forum/showthread....98#post1140098 and
See https://gm-volt.com/forum/showthread....86#post1140786
Frank Weber (Volt chief engineer, now BMW i3) also posted his personal mod along these lines. http://roulezelectrique.com/recalibr...re-de-la-volt/ (use Google Chrome browser for auto-translation) The method does appear to work.
Variation 1: Switched Resistor Under Hood
Rather than attaching the resistor directly to the sensor, attach it via a switch under the hood
See https://gm-volt.com/forum/showthread....33#post1506433
New version was here (seems to be gone now): http://www.ebay.ca/itm/Sonde-tempera.../281246258931?
New link: http://www.ebay.com/sch/i.html?_odk...Volt.TRS0&_nkw=ERDTT+Volt&_sacat=0&rmvSB=true
Also see https://gm-volt.com/forum/showthrea...tic-ERDTT-disabling-Add-on-modules-availables...
Variation 2: Switched Resistor in Cabin
You don't need to access/replace/modify the sensor itself. Add the resistor with a switch in the passenger compartment by locating the appropriate wire pair. The air temp sensor is a two-wire circuit that runs from the bumper-mounted air sensor pins, through the right side underhood area, then through the front bulkhead pass-through to the HPCM2 (Hybrid Hybrid Powertrain Control Module 2 X1) module under the front passenger seat. The circuit could be accessed and modified with a resistor anywhere between those end points.
Pin Size Color Circuit Function
26 0.35 L-BU/GY 636 Outside Ambient Air Temperature Sensor Signal
40 0.35 BK/L-BU 61 Outside Ambient Temperature Sensor Low Reference
LugNuts Implementation thread: https://gm-volt.com/forum/showthread.php?328361-All-I-want-for-Christmas-is-no-ERDTT
Resistance testing discussion by WOT and TBoult here: https://gm-volt.com/forum/showthread....-..-quot/page3
2. Covered Sensor Method
The other method is to simply slow the temperature sensor by blocking it from direct wind.
Cover the sensor or the air intake grills with 1/2 " foam pipe insulation or cardboard to keep it out of the direct wind. This will delay ERDTT but will not stop it. One who tried closing the air space between the intake grills with the pipe insulation reports: 25-30% reduction in gasoline consumption in ERDTT mode ( 2,25 l/100km to 1,75 l/100km ). because the ICE simply cycles less frequently. Testing was done on the same route every day, 130 km (81miles) per day. “No check engines, nada problems.”
See https://gm-volt.com/forum/showthread....42#post1143442
and https://gm-volt.com/forum/showthread....26#post1191426
and https://gm-volt.com/forum/showthread....50#post1514650
Reference Posts:
https://gm-volt.com/forum/showthread....n-Kit-Aero-Mod.
https://gm-volt.com/forum/showthread....42#post1143442
https://gm-volt.com/forum/showthread....-winter-Anyone
https://gm-volt.com/forum/showthread....86#post1140786
https://gm-volt.com/forum/showthread....98#post1145498
http://roulezelectrique.com/recalibr...re-de-la-volt/
https://gm-volt.com/forum/showthread....-..-quot/page3