Understand I'm not a cell phone person! Can't stand the annoying things. I happened to bring one on a trip today in my POS 2004 Mazda3. When I got in the car the door locks all clattered at the same time, twice for several seconds. Later I made a call and the dome light wouldn't respond to the switches and turn off anymore. Shutting off and restarting the car put everything right again. I know they affect computer audio systems and sometimes video, but has anybody ever seen anything like this? Random chance problem or was it really the cell phone getting involved with the alarm or computer system?
There have been similar problems in the past:
EMCIA - EMC Industry Association, Products and Members
Have a look at past "Bannana skins" section of the EMC club siteif yoiu get chance, some of the problems caused by EMI are worrying and in some cases humourous. But it is an increasing problem and one which in general is often overlooked on DIY sites.
Thisiswhy mobiles have to be switched off when near sensitive medical equipement and during take of and landing on planes.
imaginewhat problems an EMCevent could causewhen your coming in to land..
EMCIA - EMC Industry Association, Products and Members
Have a look at past "Bannana skins" section of the EMC club siteif yoiu get chance, some of the problems caused by EMI are worrying and in some cases humourous. But it is an increasing problem and one which in general is often overlooked on DIY sites.
Thisiswhy mobiles have to be switched off when near sensitive medical equipement and during take of and landing on planes.
imaginewhat problems an EMCevent could causewhen your coming in to land..
I have about 5 years of experience designing cell phones, about 10 years ago. I have always been concerned with cell phones and electronics for reasons other than my job. I build loud guitar amps!
Cell phones operate on several different non compatible standards called "MA's". MA stands for multiple access, a means for several simultaneous conversations on a single radio channel. Most 3G and 4G (3rd and 4th generation technology) MA's use continuous transmission, the radio transmitter runs continuously all the time the phone is sending data.
Some 2G and 3G MA's use TDMA (Time Division Multiple Access) to allow multiple access. The voice is digitized and the data is packetized. The base station will allow the phone to use one or more time slots on a given radio channel, which is divided up into small parcels of time that are dynamically assigned to each concurrent user. The radio transmitter is switched on during its time slot and off during the transmit time for other users at a rate from 16 to 66 mS depending on the MA.
Phones using this pulsed transmission mode are the ones most likely to cause interference with electronic devices, and the fast rising RF edges are what you hear in your cheap PC speakers. The usual offenders are GSM, iDEN, EDGE, and variants of these, since they all use TDMA. GSM is the most popular MA in the world, but all of these MA are slowly being replaced with 3G and 4G systems.
I admit to having fun in some of the big box electronics and music stores by taking a phone, cranking its RF power up to max and going into the home theater room or the hands on guitar amp room. Some electronics are succeptable to RF from cell phones, and some isn't. The low priced stuff like cheap PC speakers are usually bad, but there are some surprises. A $7000 Yamaha digital grand piano went absolutely bonkers whenever I got within a few feet of it.
When cars started getting "drive by wire" throttle control I was skeptical, but I have been unable to cause any anomalies in several cars even when a "worse case" phone was placed on the "brain box" or ran all over the sensors and actuators under the hood.
It is possible that the phone caused the anomalies that you observed, but there would likely be a secondary cause. Usually it is caused by a repair tech not reinstalling all the shielding, and grounding features originally installed in the car.
I built a hot rod Dodge back in the 80's, installing a turbo charged engine using early (1984) digital engine control into a car that was originally carbureted. I left out a lot of stuff I didn't absolutely need and made my own wiring harness from scratch. Yes, it was possible to stall that car with an iDEN phone next to the unshielded brain box board.
Cell phones operate on several different non compatible standards called "MA's". MA stands for multiple access, a means for several simultaneous conversations on a single radio channel. Most 3G and 4G (3rd and 4th generation technology) MA's use continuous transmission, the radio transmitter runs continuously all the time the phone is sending data.
Some 2G and 3G MA's use TDMA (Time Division Multiple Access) to allow multiple access. The voice is digitized and the data is packetized. The base station will allow the phone to use one or more time slots on a given radio channel, which is divided up into small parcels of time that are dynamically assigned to each concurrent user. The radio transmitter is switched on during its time slot and off during the transmit time for other users at a rate from 16 to 66 mS depending on the MA.
Phones using this pulsed transmission mode are the ones most likely to cause interference with electronic devices, and the fast rising RF edges are what you hear in your cheap PC speakers. The usual offenders are GSM, iDEN, EDGE, and variants of these, since they all use TDMA. GSM is the most popular MA in the world, but all of these MA are slowly being replaced with 3G and 4G systems.
I admit to having fun in some of the big box electronics and music stores by taking a phone, cranking its RF power up to max and going into the home theater room or the hands on guitar amp room. Some electronics are succeptable to RF from cell phones, and some isn't. The low priced stuff like cheap PC speakers are usually bad, but there are some surprises. A $7000 Yamaha digital grand piano went absolutely bonkers whenever I got within a few feet of it.
When cars started getting "drive by wire" throttle control I was skeptical, but I have been unable to cause any anomalies in several cars even when a "worse case" phone was placed on the "brain box" or ran all over the sensors and actuators under the hood.
It is possible that the phone caused the anomalies that you observed, but there would likely be a secondary cause. Usually it is caused by a repair tech not reinstalling all the shielding, and grounding features originally installed in the car.
I built a hot rod Dodge back in the 80's, installing a turbo charged engine using early (1984) digital engine control into a car that was originally carbureted. I left out a lot of stuff I didn't absolutely need and made my own wiring harness from scratch. Yes, it was possible to stall that car with an iDEN phone next to the unshielded brain box board.
Well, false alarm. The Mazda3 is still a POS and it did it again this morning with no cell phone present. Just failing electronics I guess, or maybe something related to the cold.
I should qualify my comments in that the intro year of the Mazda3 was a POS, but the later ones seem better. Most unreliable and expensive to own car I've ever had in 38 years of driving.
I should qualify my comments in that the intro year of the Mazda3 was a POS, but the later ones seem better. Most unreliable and expensive to own car I've ever had in 38 years of driving.
Try a Citroen C3, gearbox disintegrated, ECU gone duff, clutch, heater, brake calipers , two springs and a few other things in the last 8 months...spent more time in the garage than on the road recently. As to the elctronics, got a load of controls on the steering wheel, great fun, we have a lottery now on what will happen when a button is pressed, my favorite is volume up, it operates the rear wiper
P>S> it is for sale if anyone interested (well when I get a new ECU)
P>S> it is for sale if anyone interested (well when I get a new ECU)
I just turned 60, so I qualify as "older folk" and yes, I rember Mazda valves. I found a bunch in a box full of stuff I bought from an auction house, here in the USA. French manufacture I believe?
You can find POS vehicles amongst all manufacturers, although some brands seem to have made a long reputation of crap. We had a 1999 Pontiac Sunfire convertible that we managed to drive just over 3000 miles in the 2 years we had it. That's because it was always dead and in the Pontiac shop. Every time it rained, daily for about 6 months per year, the car would fill up with water and the engine control computer was under the passenger seat. The brain box was changed at least a dozen times and the entire interior was replaced twice because of mildew and mold. Traded it for a Ford Mustang convertible that we had for 7 years.....I changed the battery once, and changed the oil, thats it!
I've got my bets on a filtering capacitor gone bad somewhere in the BCM (body control module) of the car.
Possibly one on the DC input to the BCM. Same thing happened to my car.
Somewhere somehow a capacitor isn't doing its job of filtering out noise from either the ignition system or somewhere else.
Pull the BCM if you can and recap it. What you want to look for is the large electrolytics, replace one of those and you should be back in buisness.
What shocks me the most though isn't that this is occuring, its that its occuring on a 2004 model car, I wouldn't have expected it to prop up for at least another 5-10 years.
Just to add a bit of scare factor into the mix, I wouldn't be surprised if manufacturers have put caps like this into cars, stragetically placed, so that they can control the life expectancy of modern cars.
Last edited:
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.