Jan 2019

Thank 1970s Arab Oil

Hello 93636,

Last week a 2013 Ford Escape rolled into the shop with an overheating complaint. In the process of diagnostic, we discovered a Ford Technical Service Bulletin that addresses overheating complaints for certain turbo charged 1.6L Ford Escapes. Safety Recall 13S12 addresses potential localized overheating of the engine cylinder head which can result in a crack in the cylinderhead and create a fire hazarddue to leaking oil. The recall includes enhancements to the engine cooling system, engine shielding and a reflash for the Powertrain Control Module (PCM). I’m wondering how a PCM (computer) reflash can correct what appears to be a mechanical design issue? I was unable to locate any further information regarding the reflash so I suspect its purpose is to de-tune the engine and decrease stress on the cylinder head and cooling system.

Also, a 2007 Dodge Cummins diesel rolled into the shop with the same engine overheating complaint. After some challenging diagnostics we were able to determine the low side driver in the PCM was defective resulting in an engine cooling fan failure. The DodgeCummins needs a PCM replacement.

If you are wondering how a PCM reflash and a PCM replacement became the correct repair for an overheating engine, let me explain.

It all began in 1975 with the Energy Policy and Conservation Act. The EPC Act was the USA’s response to the 1973 Arab Oil Embargo. With the EPC Act, congress established federal fuel economy standards starting with new 1978 model year passenger cars and light duty trucks.The 1975 legislation was intended to roughly double average fuel mileage for new cars to 27.5 miles per gallon by 1985 and 22.2 MPG for light duty trucks by 2007. The Energy Independence and Security Act of 2007 again raised the fuel economy standards for America’s cars, light trucks and SUVs to a combined fleet average of at least 35 MPG by 2020. In 2009 the Federal Government, state regulators and the auto industry established a national program to again increase Corporate Average Fuel Economy(CAFE) standards to approximately 49.6 MPG by 2025. As of December 2017, the on-road fleet average was about 21 MPG. As you can imagine, automotive engineers are looking at every part of the vehicle for potential fuel savings.

Here are some of the technologies born as the result of increased fuel mileage compliance standards: Hybrid and Electric Vehicle Technologies; Smaller Turbo Charged Engines; Cylinder Deactivation; Idle Stop; Direct Fuel Injection; Variable Valve Timing; Variable Valve Lift; Deceleration Fuel Shut-Off; Continuously Variable Transmissions; Electric Steering; Smart Air Conditioning; Smart Charging Systems; Electric Water Pumps; Electric Engine Cooling System Fans; and Regenerative Braking. Other new technologies include plastic everything. Weight is the enemy of fuel mileage. Many vehicles now have plastic valve covers, oil pans, in take manifolds, radiators, water pumps and coolingfans. Even though everything is smaller and lighter, electrical driven components are much more efficient then their mechanically driven counterparts due to precise control by the PCM.

OK, back to our case studies.
A modern automotive, mechanically driven water pump circulates approximately 1 gallon of coolant every second. During free way driving that’s 3,600 gallons per hour, every hour. With an electric water pump the PCM modulates the impeller speed to circulate only the minimal amount of coolant necessary to maintain proper engine temperature. By reducing the amount of coolant being circulated, we reduce the energy needed to circulate the coolant and thereby increase efficiency and fuel mileage.

It turns out our 2013 EcoBoost Ford Escape had a traditional mechanically driven water pump and the PCM was not involved with its operation or failure. Our problem was just an old fashion water pump coolant leak. After the repair we recommended the vehicle be returned to a Ford dealership for the 13S12 safety revisions.

With our Dodge Cummins, Dodge used a large electric cooling fan to regulate engine temperature. During heavy engine loads the large electric fan draws massive amounts of air through a radiator to dissipate engine heat. During lighter engine loads, the PCM decreases the fan blade speed and operation because there is less heat to dissipate.Replacingthemechanicallydrivencooling fan with an electrically driven cooling fan reduces the amount of work being performed, energy consumed and thereby increases efficiency and fuel mileage.Vehicle engineers have turned to small electric motors to control many of the modern vehicle functions because they are light, reliable and can be programmed to operate in a more efficient manner.

Don’t be surprised if soon even your vehicle’s brake system becomes classified as an emission component. Non-hybrid vehicles will soon also use regenerative braking to convert the vehicle’s kinetic energy into electrical energy to recharge the vehicle’s 12-volt battery. That will decrease the load on the engine from the mechanically driven alternator.

California emissions and federal fuel mileage regulations are the driving forces for so much of today’s automotive innovation and technology. There is no doubt the modern automobile is the most complex technology that most individuals interact with on a daily basis. For us, the automotive professionals, the new technology represents a future of on-going training and learning. Themodern professional automotive technician attends more on-going training than any other industry professional that I’m aware of. OH! That’s all for now. Gotta go! It’s Saturday and I’m late for class.

As usual I’m looking for interesting and informative automotive topics to write about. If you have any suggestions, recommendations or general or specific questions about a personal vehicle, please TEXT 559-907-7661 and I will promptly reply.

God Bless America and God Bless 93636
Warren Parr
ASE Master, Hybrid and Advanced Level Certified
A 2013 & 2014 NAPA/ASE California Technician of the Year

Feb 2019

Those Annoying Lights

Hello 93636,

Last week Lori stepped into the garage to find her car with a flat front tire. I knew a rear tire was leaking air because the Tire Pressure Monitoring System (TPMS) “Warning Lamp” was illuminating from time to time. I simply re-inflate the tire and problem solved … for a while.

OK! It’stimetobuysome newtires for the wife’s car but tires are not the only consideration these days when purchasing tires. What about the Tire Pressure Sensors? Should I replace them also? Lori’s Honda is 5 years old now.

TPM sensors can be divided into two types, direct and indirect. The indirect TPM systems use wheel speed sensors to measure the rotational speed of the tires. The principle is when a tire is under-inflated, it has a shorter circumference causing it to rotate more times to travel the same distance as a correctly inflated tire. When the TPMS module sees the higher tire speed, it interprets that speed differential as an under inflated tire.

Direct TPM systems employ pressure sensors at each wheel. The sensors can be internal or external. When the air pressure inside the tire drops below a predetermined valve the TMPS Warning Lamp is illuminated. You best know that symbol as the horseshoe-shaped light with an exclamation point in the center. Most pressure sensors are located inside the tire at the bottom of the valve stem. It’s my experience you can generally identify apressuresensorsystem by the tire’s valve stem. When a pressure sensor is attached to the bottom of the valve stem, the stem is usually metal and ridged. If the valve stem is rubber and flexible, likely there is no sensor attached.

The TPM pressure sensor transmits a Radio Frequency wave to the receiver moduleinsidethevehicle. Bytheway,your remote key fob also transmits a RF signal so it’s common for those systems to share a module.

Each TPM sensor transmits its unique identification and position on the vehicle to the TPMS module. TIP: If you rotate your own tires you may need to reset your tire positions. Some vehicles can be reset with a scanner. You will need to inflate the tires in a certain sequence so the module sees the pressure increase and relearns the sensor’s new position. The vehicle will beep its horn each time a position is relearned. Make sure you reset the tire pressure to the correct setting after the relearn is complete. The correct tire pressure setting is located on the tire label on the driver’s door pillar. Usually it’s yellow. Some vehicles need a special TPMS tool to reset their tire locations. Good luck with that one.

Because the sensors are located inside rotating tires with no direct connection to an external power source, a very small internal battery is incorporated to power the sensor. The battery is not serviceable. When the first generation TPM sensors were introduced, we technicians we told the battery life expectancy is 5 years. When the battery becomes weak or damaged, the sensor will no longer transmits a clear, steady signal. If you have a constant “no display/low pressure/errormessage” from your TPMS and you can’t erase it or clear it by properly inflating the tires, you likely have one or more failed/dead tire sensors.

As far back as 1970, the U.S. National Highway Traffic Safety Administration (NHTSA) looked into the benefits of low tire pressure warning systems. An Indiana State University study suggested that under-inflated tires were the cause of 1.5 percent of all motor vehicle crashes. A later independent study by the Goodyear Tire Co. confirmed that study.

In 1979, NHTSA considered mandating low-pressure warning equipment as a means to reduce fuel consumption by the general public. A study concluded that properly inflated radial tires achieved a 3-4 percent mileage increase when compared to tires underinflated by 10 psi. At that time the technology was too expensive and the concept lost traction, so to speak. About a decade later TPMS would again become a national topic when Ford Explorer’s began rolling over due to failed Firestone tires. Ford’s internal documents showed that Ford engineers early on discovered the propensity of Ford Explorers to roll over during high speed evasive maneuvers. Recommendations were made to modify the suspensions and increase axle width, but those recommendations were rejected in part because of increase costs and time considerations. The Ford Explorer release date would have been delayed by one year.

Ford’s solution was to reduce the Explorer’s tire air pressure to 26 psi. The low tire pressure however accelerated heat buildup within the tire causing the tire tread to separate from the tire carcass. Ford’s solution created the same hazard they were trying to mitigate. You guys know I have become a Ford fan during the past decade or so, but I think Ford made a bad decisionwith this one.

The U.S. Congress got involved and passed the Tire Recall Enhancement, Accountability, and Documentation (TREAD) Act of 2000. The TREAD act mandated all passenger vehicles weighing under 10,000 pounds sold in the U.S. as of September 1, 2007 will be equipped with a Tire Pressure Monitoring System capable of warning drivers if a vehicle’s tire is underinflated by 25 percent or more. All 2008 model year vehicles or later sold in the U.S. are equipped with TPMS as standard equipment. WARNING!!! DO NOT DISARM THE TPMS!!! IF THAT VEHICLE IS INVOLVED IN AN ACCIDENT CAUSED BY A DEFECTIVE OR LOW TIRE YOU WILL BE LIABLE.

Now you know why your vehicle has that annoying TPMS lamp, why it’s illuminated even though the tire pressure is correct and why my industry will not remove the TPMS bulb. It’s been my experience TPM sensor life is closer to 8-10 years. Therefore, I decided to keep my money and not replace my sensors at this time. I will let you know in a future article if that was a wise decision.

OK guys, that’s all for today. As usual I’m looking for interesting automotive world topics to write about. If you have any suggestions, recommendations, thoughts or questions regarding my industry and/or a specific or general question about a vehicle, please text me at 559-907-7661 and I will respond in a timely fashion.

God Bless America and God Bless 93636
Warren Parr, ASE Master, Advanced Level
and Hybrid Certified Technician


5787 W Barstow
Fresno, CA 93722