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logo Ultra Low Sulfur Diesel issues

UPDATE: As of late Septemebr, 2018, it appears conversion to ULSD is complete. See the fiorst paragraph in this announcement from Pemex:

As you may or may not be aware, most parts of Mexico still do not have ULSD diesel available which is prescribed for diesel pickups built after mid 2007. We lose a lot of potential customers over this issue, but we have also had many customers who have chosen to go anyway, as has been the case with many other Caravan companies. We have compared notes with them, and to date, nobody has experienced issues with the limited number of tankful's of LSD used on a caravan. We know individuals who claim to have driven over 25,000 miles in Mexico with no issues (see Face book conversation Link). Ted White has done extensive research on this subject and while we still have to warn customers that if they take a late model diesel into Mexico, it is at their own risk, we feel this will assist them in being better informed and ease their concerns. I should point out that ULSD is available in Northern Baja, close to the border in Mainland Mexico and in Mexico City & Guadalajara ( & maybe Morelia). If it is available, no Pemex station will state if it is or not. However, Ted has had some samples tested in Northern Baja, and they have in fact turned out to be ULSD.

Here is the key to avoiding problems: If you do take a late model diesel down, you should only use it to get from point A to B towing or carrying your RV. Do not use it for local transportation. This will minimize fuel used and ensure the engine is under load, and less likely to build up sulfur in the filter.


So here is what Ted has to say on the subject:

1) There are ZERO issues with 2007.5 through 2010 model years of Ford, GM, and Dodge diesel pickups using LSD, loaded, towing, or unloaded. The only evidence that LSD is being burned is the occasional smokey regeneration cycle (blue smoke from the exhaust for short periods of time). 

2) For model years 2010 through 2012, there are no issues for Ford, GM or Dodge as long as the truck is towing a moderate to heavy trailer. If the truck is driven without a load, owners can expect occasional engine light illumination, and GM owners can expect to see speed limitation warnings from time to time. These conditions are self limiting and disappear after the next regeneration cycle.


For 2011 and later Ford and GM, and 2014 and later Dodge, it is important that owners carry at least 2 times the normal amount of DEF (Diesel Exhaust Fluid) as consumption will increase while in Mexico due to sulfur poisoning. In addition, it is very difficult to source DEF in Mexico.

3) For 2013 through 2014 model years, neither Ford nor Dodge has issues other than occasional engine lights if the truck is NOT loaded. GM vehicles will need forced regeneration assistance to avoid limp mode if driven unloaded. No issues for any of these trucks if they are driven only with a moderate to heavy trailer in tow.

4) Data is still being gathered for 2015 model years, but the data to hand suggests that unloaded GM vehicles will need forced regeneration assistance, Ford MIGHT experience issues, and Dodge is unaffected. No evidence of problems if the vehicle is towing a heavy trailer.

An article on the subject is posted below:

FOR 2007.5 - 2015 PICKUP OWNERS

For those new to this topic, Mexican diesel fuel presently contains up to 500 ppm of sulfur, while the Ultra Low Sulfur Diesel (ULSD) sold in Canada and the USA is just 15 ppm. Unfortunately, the higher sulfur Mexican diesel can cause temporary “sulfur poisoning” of the emissions system for some pickup trucks with diesel particulate filters (DPF) and selective catalytic reducers (SCR). (DPFs were introduced in late 2007, SCRs were added by Ford and GM in 2011, and Dodge introduced SCRs in 2014). Your pickup truck has both DPF and SCR technology if you add Diesel Exhaust Fluid (DEF) to a separate on-board tank.

2011-2012 Dodge :

From Ted White:

The EPA set new and stricter limits on NOX emissions from diesel engines starting in 2011. There were two ways that manufacturers could achieve the new targets. One was to introduce an SCR (Selective Catalytic Reducer) that used DEF (Diesel Exhaust fluid) to reduce NOX.  The other method was to increase the amount of exhaust gas being fed back through the engine. This second method starves the engine of oxygen which then gets stripped from the NOX during combustion.
Ford and GM decided to go with DEF in 2011, while Dodge decided to increase the amount of exhaust gas recirculation.  Dodge used this decision as a sales tactic against Ford and GM, appealing to buyers who were wary of the DEF based systems, but they had to switch to DEF in 2013 because emissions targets were once again made more strict by the EPA.
I've been told that there are two main downsides to using increased exhaust gas recirculation.  The first is lower power, and in 2011/12 Dodge fell behind GM and Ford on engine power.  The second main downside is the handling of increased amounts of exhaust gasses through the EGR (Exhaust Gas Recirculation) system.  These gasses are very corrosive, and contain traces of oil along with carbon and other compounds which gradually accumulate in the EGR until they begin to block it and cause fault codes.  It takes a few years for the clogging to become a problem, but many owners of Dodge 2011 and 2012 vehicles now seem to be running in to the need to have the EGR system cleaned. 


Despite the potential for emissions system problems on DPF/SCR equipped pickups, laboratory testing prior to 2007 suggested that 2007.5 through 2010 model year diesels, whether Ford, GM, or Dodge, would tolerate well the higher sulfur Mexican diesel. This has indeed turned out to be the “real world” situation. There can be occasional bluish exhaust smoke during regeneration cycles, but no serious fault conditions are triggered. In addition, testing prior to the release of DPF equipped pickups confirmed that there would be no permanent damage to the emissions system, as long as higher sulfur fuels were not used for more than 40,000 continuous miles.

For 2011 and 2012 model years, some owners have been experiencing occasional engine light illumination, and “DEF QUALITY POOR” warnings. Those warnings typically disappear, however, following a 15 minute high speed run, OR during subsequent heavy trailer towing, OR after the next regeneration. All of these situations usually raise exhaust gas temperatures high enough to purge sulfur compounds from the system. 

DEF QUALITY POOR warnings tend to occur a few weeks after a fifth wheel or other heavy trailer has been disconnected, and the truck is being driven around locally in Mexico. Lower exhaust temperatures while unloaded permit the buildup of sulfur compounds, reducing the efficiency of the emissions system until an error code is triggered. The Diesel Exhaust Fluid is NOT the culprit in these cases, even though that is the message displayed. It is simply a matter of the engine computer thinking that higher than expected NOX (oxides of nitrogen) in the exhaust is evidence that the DEF is not doing its job.


In 2013, Environmental Protection Agency monitoring requirements for NOX in the exhaust became much stricter. Monitoring is more frequent, and NOX must remain within a tighter tolerance level. In addition, regenerations to burn off the soot and sulfur compounds are less frequent. As a result, 2013 and later model year diesel pickups are more likely to register fault codes while in Mexico, and clearing the codes is more complex.

Also for GM 2013 and later model years, the distance which can be traveled after a DEF fault is triggered, and before “limp mode” (maximum speed 4mph) is initiated, gets accelerated with time. This means that the available non-limp-mode miles often disappear more quickly than warranted by the distance traveled, creating a stressful experience for owners.

Luckily, not every owner will experience such fault conditions, but when they happen, the key is to get the truck to do a regeneration as soon as possible. Once the emissions system is cleared of sulfur compounds by the heat of a regeneration cycle, the engine computer stops thinking that there is a problem with the DEF, and the fault condition disappears. It is critical that a regeneration be initiated well before limp mode occurs, because the vehicle must be driven at highway speeds for about 35 minutes during a regeneration.


Unfortunately, there is no direct method for an owner to force a regeneration, but some pickup models have an indirect method based on EPA requirements that regenerations must occur approximately twice as often if there is a problem with the DPF pressure sensors. So, disconnecting the DPF pressure sensors can sometimes force a regeneration, provided that more than half the normal distance between regenerations has already been traveled. 

Typically, immediately after disconnecting the DPF pressure sensors, the driver will see a message that soot filter cleaning has started and to keep driving at highway speeds until it is finished. If half the normal distance between regenerations has not yet been traveled, it could be up to 200 hundred miles before a regeneration is triggered, but odds are, for a fault to have been triggered by excess sulfur buildup, it is likely that more than half the normal distance since the last regeneration has already been traveled. Information is available from the author ([email protected]) on how to unplug the DPF pressure sensors on some 2013 and later model years, but forcing a regeneration is significantly more complicated if limp mode has already occurred. 

Edge does have some new tuners out that will force a regen cycle for Ford & GM, but not for Dodge (as far as I know).  For GM it is the "Edge 25003", for Ford, its the "Edge CS/CTS or EvoHT". This will eliminate problems but I understand a DPF filter only has so many regen cycles in it (don't take my word for that), so they may reduce its life and DPF filters cost about $10,000 to replace. 

Unfortunately, in mid-February of 2015, Pemex cancelled the ULSD refinery upgrades it had announced in September of 2014 - upgrades which would have made ULSD available across Mexico by early 2016. This means that most Mexican diesel fuel will continue to be LSD for the next few years. The big unknown is whether the competitive outlets, like Gulf Oil, starting in May 2016 will have ULSD imported from the US. Certainly not for the first year, but possibly in early 2018.

Irrespective of the manufacturer of your pickup though, if it also requires Diesel Exhaust Fluid, be sure to take at least 7 gallons with you into Mexico, because DEF consumption will increase, and even double, as the system tries to compensate for temporary sulfur poisoning of the emissions system. DEF is available from some Napa Auto Parts and heavy truck service centers on special order, but the price can be twice as much as in the USA. Update Spring 2016, I now see DEF fluid available in all Autozone stores which are common in Mexico.

Owners needing more specific information, or with a personal experience to share, can contact Ted at [email protected]. Please note though that the information provided in this article, and to any owners who need assistance, is provided only in the interests of sharing of knowledge, and should not be interpreted as an endorsement or encouragement by the author for owners of 2007.5 and later pickup trucks to drive them into Mexico. 

Ted White

February 19, 2015

Kelowna, Britsh Columbia  

Ted updates this frequently. For his latest update in Ms Word Format, click HERE


Update September, 2016 from Ted:

Based on all of the available data, none of the Ford, GM, or Dodge diesel pickups up to, and including, the 2010 model year, have any significant issues with the higher sulfur levels in Mexican fuel.  I do not have in my files a single reported case of a problem for any pre-2011 Ford or Dodge diesels. 

GM Duramax diesels 2007.5, 2008, and 2009 exhibit no issues other than smoky blue exhaust during regeneration cycles as the sulfur compounds burn out of the emissions system. GM Duramax diesels 2010 sometimes turn on the Check Engine Light for a while between regenerations but are "self-healing".

Ford diesels 2011 (when DEF was introduced) through 2015 appear to have zero problems.  I have ONE 2016 Ford case on file but I suspect this was due to a component failure, not Mexican diesel fuel.

I do not have a single case on file of any Dodge diesel, of any year, having issues any worse than the Check Engine light on from time to time. Dodge diesels do suffer from generous consumption of DEF while on Mexican diesel.

I do not recommend any GM Duramax owner 2011 through 2016 going in to Mexico unless they first work with me to learn how to manage the serious reactions their trucks will have to Mexican diesel.

So, based on my database records, and the reports of owners on line over the years since 2008;

I would allow GM diesels through 2009.
I would allow Ford diesels through 2015
I would allow Dodge diesels of any year

I would not allow GM diesels 2011 and later unless they could show that they had worked with me to learn how to manage their trucks.


If you do need a new DPF Filter

If you do have to change out your DPF, don't go to a dealer and buy a pricey OEM. Look at Reflow Solutions in Vancouver, BC. They sell replacement DPF filters that are cleanable, for $1250-$1500 Canadian, compared to $5000+ for originals. These filters can be cleaned & reused for the life of the vehicle. Once the cleanable unit is purchased from Canada, the authorized US agent to clean them is CDS if you are not in Canada.