These questions are representative of questions received from many Volvo forum correspondents. Hopefully you will find the answer you are looking for. If not check out http://VEXEDvolvo.org as it has much more technical detail on the Volvo Magneti Marelli ETM problem. If you still do no find what you need send an e-mail from the Contact Us page or e-mail me at throttle@FixYourETM.com.
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Why should I buy a remanufactured ETM from XeMODeX rather than going to my Volvo dealer?
First and foremost,- the Volvo potentiometer throttle position sensor (TPS) wears out, the XeMODeX Digital Angle Sensor (DAS) has no rubbing parts to wear out and carries a lifetime limited warranty against failure of the DAS.
The Volvo warranty, after the initial 10-year or 200,000-mile warranty, is only one year on parts and service.
Replacing the XeMODeX remanufactured ETM can be done by an independent mechanic, most auto repair chains or by a competent do-it-yourself mechanic. It is not as difficult as changing an alternator or starter.
The Volvo ETM, with the potentiometer (the volume control knob on a radio turns a potentiometer) as a TPS, is a time bomb than can fail anytime, anywhere and there are not Volvo dealers on every corner and often not within hundreds of miles.
The Volvo ETM can only be replaced by a Volvo dealer as they are the only ones with the computer and Internet connection to VCNA to download and initalize the new (never installed on a car) ETM.
By sending your ETM in for rebuilding, the internal computers do not see any difference in the electrical signal from the DAS, so computer software downloads are generally not required.
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What is an Electronic Throttle Module?
Question: What is wrong with this statement:. "I'm in a hurry, step on the gas?"
Answer: You 'step on the air'. In a gasoline engine the accelerator controls the air by opening or closing a valve called a throttle. The amount of fuel used is determined by the air flow through the Air Mass Sensor and the fuel mixture as measured by the oxygen sensors.
In the grand scheme of things, the accelerator sends a signal to the throttle telling it to open a certain amount. The throttle opens, but to be sure, the throttle tells the computer how much it has opened by sending a feedback voltage, proportional to the throttle position. The various computers work together to give smooth and rapid response.
So what is the problem? In the Volvo Magneti Marelli ETM, the throttle moves a series of copper alloy wiper fingers that scrape across a fragile film of carbon paint (imagine your fingernails scraping back and forth over a painted chalk board.). After many thousands of movements the fingers wear through the paint and the feedback signal no longer gives accurate position information. The throttle then begins to hunt back and forth as driven by the computer. This causes surging, hesitation, stalling and unexpected acceleration. When the film finally wears though the computer says to the throttle, "I cannot understand you so I am shutting down, your are on your own." A pair of springs within the throttle body then open the throttle to a position that sets the engine to a speed sufficient to engage the automatic transmission but not so fast but what the brakes can stop it. This is called the "limp home" mode. There are two indications that the car is in the limp home mode, the "Check Engine": light will be on and the accelerator pedal is completely disabled.
While other cars also use the 'fly by wire" electrical control of the throttle, the Volvo is the first to incorporate a very smart computer within the electronic throttle body. Due to the complexity of the throttle body it is not possible to replace the potentiometer strips. The whole ETM must be replaced and calibrated to the car by a computer hookup to the Volvo Cars North America web site. Independent mechanics do not have this capability.
As stated before, XeMODeX has developed a throttle position sensor (They call it a Digital Angle Sensor) that has non-contacting parts that measure the throttle position so there is nothing to wear out. The
XeMODeX carries a lifetime limited warranty for the car it is originally installed on.
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What vehicles can use the XeMODeX ETM?
With Volvo model year 1999 (delivery starting in late 1998) through model year 2001 and a few 2002, Volvo incorporated an ETM manufactured by Magneti Marelli. (Magneti Marelli S.p.A. is an Italian company which deals with development and manufacturing of systems, modules and high-technonlogy components for the automotive industry. It is a subsidary of Fiat Group.) This ETM is smart. It takes signals from the accelerator and does magical things to it, and generates a duty cycle DC signal that drives the throttle position motor. Many cars now use the resistor type throttle position sensor but have a small motor and double gear reduction drive to drive the throttle plate from closed to full open..
The following are the cars with the Magneti Marelli ETM.
VOLVO / C70 1999-2002
VOLVO / C70 CONVERTIBLE 1999-2001
VOLVO / COTTRELL 1999
VOLVO / S40 2000-2001
VOLVO / S60 1999-2002
VOLVO / S70 1999-2000
VOLVO / S80 1999-2001
VOLVO / S90 1999
VOLVO / V40 2000-2001
VOLVO / V70 1999-2002
VOLVO / V70XC 1999-2001
VOLVO / V90 1999
VOLVO / VOLVO 1999-2001
VOLVO / X70 1999
VOLVO / XC70 2001
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Where can I find more information?
- http://VEXEDvolvo.org is the predecessor to this site and contains detailed information on the Volvo ETM problem.
- http://www.XeMODeX.com is the Canadian manufacturer who applied a non-contacting sensor technology to correct this problem.
- http://www.matthewsvolvoforum.com, click on "Forums" and go down to "Don's ETM Room."
- A web search on "ETM", "Willson", "VOLVO", and "Forum" in any combination will get thousands of hits.
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Why did Volvo not Fix this Problem?
Volvo is well aware of the problem but chose to ignore the magnitude of the problem. Their phlosophy was, "Replace a few under warranty then let the customer pay." World wide attention by a class action lawsuit in California, the California Air Resources Board, The National Highway Traffic Safety Administration, VEXEDvolvo.org, TV reports and many other factors forced a recall. The recall did not address fixing the potentiometer throttle position sensor but only made the ETM software less sensitive to pending failures, thus reducing the replacement of ETMs that were showing symptoms of failure but had not failed (yet). California said that the fuel system must be warranted for 10 years to reduce pollution. Since Californians drive about 14,000 miles a year they just rounded it up to 200,000 miles.
The extended warranty is only with Volvo Cars North America, the rest of the world is only covered by the normal new car warranty.
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Can I get parts and fix the ETM myself?
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Yes and no. Yes, you can send your ETM to XeMODeX, they will remanufacture it and send it back the next day.
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No, you cannot buy the parts and install them yourself. It is beyond the capabilities of the DIY mechanic, it requires opening up sealed components, adding wires, test equipment and other operations
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Can you fix the old ETM by replacing the resistance strips? Absolutely not. This question has been asked time and time again. There is no source for the potentiometer films and you would not eliminate a potential failure, only delay the failure.
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What about Mercedes Benz throttle bodies? There is nothing similar about them, they are 'dumb' and have no electronics. Most throttle bodies have a small motor the drives a 2 gear, gear train so that many turns of the motor only turn the throttle plate about 85°. The Volvo/MM ETM has a big magnet as an armature and very heavy field coils and it turns the throttle plate directly.
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Can I get the XeMODeX at my independent dealer?
Not yet. XeMODeX is working on finding distributors and getting the word out to dealers. One problem is the lack of cores (parts removed from a car that are rebuildable.). ETMs removed from cars by dealers are returned to VCNA for testing, it if is truly bad the dealer is reimbursed, if not he is charged for the part. This is one reason why the Authorized Volvo Dealers are very reluctant to replace ETMs based on driveability symptoms, a specific OBD code is required. If the Campaign 155 software download has NOT been performed, the dealer must do this first under a recall. This may remove the poor driveability symtoms but only delays the final limp-home failure.
Yes: If your independent mechanic/dealer is also in the Volvo salvage business, as many are, they might have a core they can send to XeMODeX, have it rebuilt and exchange it in your car, about a 2 hour job. Caution: There are several varieties of software depending on the car model. If you replace an ETM from a different model it may or may not work. It might run fine, it might start but go into limp-home mode or it might not start. So be prepared to have the software RELOAD performed by a Volvo dealer after installing an XeMODeX rebuilt ETM.
However, if you can spare the car for a few days, you or your mechanic can remove your ETM, have it rebuilt and have your car back in service in one business day plus shipping time. No software down load should be required.
