Tyler-98-W68
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Colder temperatures have finally arrived where I live and have allowed me to do some more testing with my 4xe and how it reacts and operates in cold weather. If you don’t want to read anymore I’ll summarize here. You can drive a 4xe in -20c weather with some tricks.
A few weeks back I installed a 20w heat pad on my ambient temperature sensor. This allowed me to trick the 4xe in to thinking the ambient temperature was warmer than it really was. This was done because the 4xe will go to hybrid mode and lock out electric mode in ambient temperatures below -12c.
I found that this worked but while driving in electric mode for a while the ICE would start up, despite the ambient temp being well above the threshold for lock out electric mode.
Through more testing I found that when the catalytic converter temperature was read as below 0c, the ICE would start up and warm the catalytic converter above zero. So I’ve established that if you take ambient temperature out of the equation you can run electric only mode, except when the catalyst temps are too low.
There are other variables that affect whether the ICE is going to start. Engine oil temperature is one of the other triggers. When the engine oil is below 0c the ICE tends to start up, if all the other parameters are met (Ambient temperature and catalyst) In my testing the ICE will trigger sometimes and only run for a few seconds and get the oil temp above 0c, other times it will run until the oil temp reaches 50c. The 50c threshold seems to happen when its very cold out, once the oil gets to that temp the Oil temp PID goes TRUE and you can go back in to electric mode providing the parameters are met.
To combat this oil temperature issue (ICE doesn’t trigger with oil temp above 0c) I installed an oil pan heater (125w) on my Rubicon. Unfortunately there isn’t many large flat surfaces to put an oil pan heater on the 4xe, so the 125w fit and worked but not very well. I then traded in my Rubicon and decided to put a 250w oil pan heater on my Sahara. It works better but not as well as I thought it would. At 0c Ambient temp it can get the oil temp up around 15c. Last night parked outside for 12 hours in -30c weather it was able to keep the oil temp at -10c, good but not what I was hoping for. I haven’t had any “middle” temperatures to see how it reacts in the -10c range.
So we have Oil Temp, Ambient Temp, Catalyst Temp all contributing to whether or not the 4xe can operate in electric mode in cold weather. As I’ve mentioned before. Its all or nothing on the 4xe as soon as 1 thing triggers a FALSE value in the PID’s the ICE runs. In very cold temperatures it can be a challenge to ensure all 3 (plus more) of the PID’s controlling electric operation can be met. That is why the 4xe doesn’t operate in electric mode below the -12c threshold.
The easiest way I’ve found to satisfy all those requirement is park inside my garage. I generally don’t heat it and even in the very cold weather its between 0 to -5c inside my garage. The odd time I will heat it. Being in a garage shelters it from the elements and allows
If my 4xe stays in the garage and I do my regular commute of 5kms to work, I can drive in all electric. I turn on the ambient temperature sensor warmer, precondition the battery for a few minutes and then drive to work. While at work depending on the ambient temperature I either drive home in electric or the ICE starts briefly. When I start my “cold soaked” 4xe. I turn on the ambient temp sensor warmer and precondition the battery. If the ICE starts it stays running for a few seconds or up to 2 minutes and which point I can select electric only mode and drive home.
If your 4xe doesn’t have the ability to park inside a garage or any other sheltered place, its going to run the ICE, really no way around that. There are times when you can get some electric operation in cold weather, but it requires the ICE to start and get other parameters up to temperature which could/will cause FORM. That works fine but once the ambient temperature goes below -12c there is nothing you can do the ICE is going to start. Basically what I’m saying is Ambient temperature rules over all the other parameters on the 4xe for electric only operation.
Now with that explanation and information out of the way, lets take a look at some pictures and video logs from J-Scan.
The first log is from a highway drive from yesterday. My vehicle started being parked in the garage, oil pan heater on and battery preconditioned. I had to do a highway drive to work. Ambient temperature was -24c. I was able to drive approximately 9 kms on the highway before the ICE kicked in. The trigger was ambient temperature because my temperature sensor was unable to keep up with the cold air hitting the front at 60mph (even though I have the front grill sealed off the best I can) The other parameters were not causing the ICE to trigger. The ambient temperature did it first. After the ICE turned on I pulled over for a few minutes, then started driving again, the ambient temp sensor “caught up” and the temp went back above the -12c threshold and electric only mode was back.
Once the ICE is started there are some other PID’s that go false, and then true. I’ve highlighted them in the picture I posted. The sequence is as follows
Once the ICE starts other engine off PID’s become active and must achieve the appropriate values before allowing the engine to turn off. It’s interesting to note that a lot of these parameters don’t apply as long as the ICE is off and driving in electric mode, but once the ICE is triggered they need to be met to get the ICE to turn off again.
So I can’t drive on the highway very long in ambient temps below -12c because my temperature sensor can’t keep up. I expected that, however driving around town in stop and go traffic I’m able to have the ambient temperature sensor heat pad keep what the vehicle thinks is a temperature above -12c thus allowing electric only operation if all other parameters are met.
As mentioned before the vehicle takes temperature from a variety of sensors on the vehicle and averages them out. The temp sensor in the grill has the most effect in changing what the temperature is. In my J-Scan logs I’m using a temp sensor in the PCM (Engine computer) but the most accurate one is actually in the BCM (body control module). I have to use the PCM PID because I can only log in J-scan from 1 module at a time. I’ve found that what is displayed on the Uconnect screen is an average temperature PID, but it does not always match what is being displayed on the PCM temperature PID. The PCM temperature PID is accurate in the sense that when it reaches the -12c threshold (or close to it) it triggers the ICE.
When I bought my heat pads (20w each) I bought 4 of them. Today I wired the other 3 in behind the front grill cover in and around the temp sensor. I then went for a drive in -20c weather (also a very windy day ~ -33c windchill) With the additional heat pads I was able to do the round trip loop of my commute to and from work (10kms) all in electric without any issue. I had the HVAC settings to 24c, defrost and low vent on fan setting 3. That combined with the heated seats and steering wheel made it completely comfortable to drive around in silence! The range really wasn’t that bad either. After a 10km city drive I still had 63% battery life, giving me approximately a 23kms range. Much less than in the summer (~40kms) but more than enough for my type of commuting in the winter.
Summing things up.
The 4xe can operate in very cold weather in the winter time when all parameters are met for engine off operation.
99% of the time you can’t reach all those parameters and missing even 1 of them will cause the ICE to run.
You can use things like oil pan heaters, tricking the ambient temperature sensor but they only work in certain circumstances. I don’t recommend anyone go out and do what I’ve done. Although an oil pan heater is not a bad idea.
Enjoy your 4xe in the winter, the electric heater provides heat quicker than a regular vehicle, and the mileage is still better than a Non PHEV.
A few weeks back I installed a 20w heat pad on my ambient temperature sensor. This allowed me to trick the 4xe in to thinking the ambient temperature was warmer than it really was. This was done because the 4xe will go to hybrid mode and lock out electric mode in ambient temperatures below -12c.
I found that this worked but while driving in electric mode for a while the ICE would start up, despite the ambient temp being well above the threshold for lock out electric mode.
Through more testing I found that when the catalytic converter temperature was read as below 0c, the ICE would start up and warm the catalytic converter above zero. So I’ve established that if you take ambient temperature out of the equation you can run electric only mode, except when the catalyst temps are too low.
There are other variables that affect whether the ICE is going to start. Engine oil temperature is one of the other triggers. When the engine oil is below 0c the ICE tends to start up, if all the other parameters are met (Ambient temperature and catalyst) In my testing the ICE will trigger sometimes and only run for a few seconds and get the oil temp above 0c, other times it will run until the oil temp reaches 50c. The 50c threshold seems to happen when its very cold out, once the oil gets to that temp the Oil temp PID goes TRUE and you can go back in to electric mode providing the parameters are met.
To combat this oil temperature issue (ICE doesn’t trigger with oil temp above 0c) I installed an oil pan heater (125w) on my Rubicon. Unfortunately there isn’t many large flat surfaces to put an oil pan heater on the 4xe, so the 125w fit and worked but not very well. I then traded in my Rubicon and decided to put a 250w oil pan heater on my Sahara. It works better but not as well as I thought it would. At 0c Ambient temp it can get the oil temp up around 15c. Last night parked outside for 12 hours in -30c weather it was able to keep the oil temp at -10c, good but not what I was hoping for. I haven’t had any “middle” temperatures to see how it reacts in the -10c range.
So we have Oil Temp, Ambient Temp, Catalyst Temp all contributing to whether or not the 4xe can operate in electric mode in cold weather. As I’ve mentioned before. Its all or nothing on the 4xe as soon as 1 thing triggers a FALSE value in the PID’s the ICE runs. In very cold temperatures it can be a challenge to ensure all 3 (plus more) of the PID’s controlling electric operation can be met. That is why the 4xe doesn’t operate in electric mode below the -12c threshold.
The easiest way I’ve found to satisfy all those requirement is park inside my garage. I generally don’t heat it and even in the very cold weather its between 0 to -5c inside my garage. The odd time I will heat it. Being in a garage shelters it from the elements and allows
- The oil pan heater to warm the oil temp above 0c
- Residual heat from the oil pan heater warms the catalyst above 0c
- Preconditioning the battery which also has a heating effect on the catalyst (no idea how/why)
If my 4xe stays in the garage and I do my regular commute of 5kms to work, I can drive in all electric. I turn on the ambient temperature sensor warmer, precondition the battery for a few minutes and then drive to work. While at work depending on the ambient temperature I either drive home in electric or the ICE starts briefly. When I start my “cold soaked” 4xe. I turn on the ambient temp sensor warmer and precondition the battery. If the ICE starts it stays running for a few seconds or up to 2 minutes and which point I can select electric only mode and drive home.
If your 4xe doesn’t have the ability to park inside a garage or any other sheltered place, its going to run the ICE, really no way around that. There are times when you can get some electric operation in cold weather, but it requires the ICE to start and get other parameters up to temperature which could/will cause FORM. That works fine but once the ambient temperature goes below -12c there is nothing you can do the ICE is going to start. Basically what I’m saying is Ambient temperature rules over all the other parameters on the 4xe for electric only operation.
Now with that explanation and information out of the way, lets take a look at some pictures and video logs from J-Scan.
The first log is from a highway drive from yesterday. My vehicle started being parked in the garage, oil pan heater on and battery preconditioned. I had to do a highway drive to work. Ambient temperature was -24c. I was able to drive approximately 9 kms on the highway before the ICE kicked in. The trigger was ambient temperature because my temperature sensor was unable to keep up with the cold air hitting the front at 60mph (even though I have the front grill sealed off the best I can) The other parameters were not causing the ICE to trigger. The ambient temperature did it first. After the ICE turned on I pulled over for a few minutes, then started driving again, the ambient temp sensor “caught up” and the temp went back above the -12c threshold and electric only mode was back.
Once the ICE is started there are some other PID’s that go false, and then true. I’ve highlighted them in the picture I posted. The sequence is as follows
- Ambient Temp triggers Hybrid PID which triggers ICE
- Engine Oil Temp PID triggered
- Engine Run Time PID triggered
- Catalyst Temp PID Triggered
- Engine Run Time PID Goes to TRUE
- Catalyst Temp PID Goes TRUE
- Engine Oil Temp PID Goes TRUE after 50c oil temp reached
- Ambient Temp goes above -12c Threshold Hybrid PID goes TRUE
- ICE Turns off
Once the ICE starts other engine off PID’s become active and must achieve the appropriate values before allowing the engine to turn off. It’s interesting to note that a lot of these parameters don’t apply as long as the ICE is off and driving in electric mode, but once the ICE is triggered they need to be met to get the ICE to turn off again.
So I can’t drive on the highway very long in ambient temps below -12c because my temperature sensor can’t keep up. I expected that, however driving around town in stop and go traffic I’m able to have the ambient temperature sensor heat pad keep what the vehicle thinks is a temperature above -12c thus allowing electric only operation if all other parameters are met.
As mentioned before the vehicle takes temperature from a variety of sensors on the vehicle and averages them out. The temp sensor in the grill has the most effect in changing what the temperature is. In my J-Scan logs I’m using a temp sensor in the PCM (Engine computer) but the most accurate one is actually in the BCM (body control module). I have to use the PCM PID because I can only log in J-scan from 1 module at a time. I’ve found that what is displayed on the Uconnect screen is an average temperature PID, but it does not always match what is being displayed on the PCM temperature PID. The PCM temperature PID is accurate in the sense that when it reaches the -12c threshold (or close to it) it triggers the ICE.
When I bought my heat pads (20w each) I bought 4 of them. Today I wired the other 3 in behind the front grill cover in and around the temp sensor. I then went for a drive in -20c weather (also a very windy day ~ -33c windchill) With the additional heat pads I was able to do the round trip loop of my commute to and from work (10kms) all in electric without any issue. I had the HVAC settings to 24c, defrost and low vent on fan setting 3. That combined with the heated seats and steering wheel made it completely comfortable to drive around in silence! The range really wasn’t that bad either. After a 10km city drive I still had 63% battery life, giving me approximately a 23kms range. Much less than in the summer (~40kms) but more than enough for my type of commuting in the winter.
Summing things up.
The 4xe can operate in very cold weather in the winter time when all parameters are met for engine off operation.
99% of the time you can’t reach all those parameters and missing even 1 of them will cause the ICE to run.
You can use things like oil pan heaters, tricking the ambient temperature sensor but they only work in certain circumstances. I don’t recommend anyone go out and do what I’ve done. Although an oil pan heater is not a bad idea.
Enjoy your 4xe in the winter, the electric heater provides heat quicker than a regular vehicle, and the mileage is still better than a Non PHEV.
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