Case Study: BMW Charging system communication error

This month the vehicle in question is a 2003 BMW 545. Powered by a 4.4 litre V8, this 1600 kg BMW should hit 60 mph in around 5.8 seconds. Sadly for this customer consistency was not a strong point on this vehicle, with sporadic instrument panel illumination, auto transmission faults, occasional non-starts, and lack of response from the gas pedal, all meant any performance was rarely seen.

Steve Smith explains...

I don’t know about you, but there are times when I cringe at the amount of technology loaded into one vehicle and the potential for things to fail. The good news is, the more they load in the more opportunities pour out when they go wrong. Here is one such vehicle that has been suffering from repeated breakdowns as a result of what proved to be overvoltage.

You can continue reading the BMW 545 case study online...

New accessories

The 1st March sees a whole host of new accessories being launched to further expand your PicoScope kit:

Fuse extension lead kit PP967 Including (also available separately): • TA035 - Mini-ATC fuse extension lead • TA034 - Standard ATC fuse extension lead • TA206 - Maxi fuse extension lead • TA168 - JCASE Fuse extension
Breakout leads • TA190 - 2-pin ACS breakout lead • TA191 - 3-pin Kostal breakout lead • TA192 - 2-pin Deutsch breakout lead • TA193 - 4-pin Deutsch breakout lead • TA194 - 2-pin Kostal breakout lead

Customer Question

Steve Smith, Automotive Applications Specialist from Pico's Automotive Technical Support, answers a customer query.

Why should I purchase an oscilloscope when I can use a multimeter to measure various circuits?

This question is one that crops up time and time again when we introduce the new users to PicoScope. We often attend trade events where we include a short presentation containing an image that really does say it all.

So what are the advantages?
Let’s take a look at the update speed or refresh rate of our typical multimeter (which remains a must havetool).

When we measure a component for voltage (a bulb for example) the circuit is reasonably straightforward in that we have a 12 V supply to the bulb and a 0 V ground reference. The display on the multimeter reads 12 V and the bulb illuminates. Now let’s introduce a poor connection into the same circuit that reduces the supply voltage when we wiggle the wiring. What may happen here is that the bulb will momentarily flicker as we wiggle the wiring and the multimeter may display a fall in voltage but only if it exceeds a specific duration, otherwise the multimeter may continue to display 12 V. In this scenario the technician could incorrectly assume the supply voltage is OK and move onto other tests that are not applicable.

The waveform below simulates the drop of a 5 V power supply during a wiggle test.

You could argue that a multimeter with a Min/Max feature (whereby the meter records minimum and maximum voltages during the wiggle test) would capture this fall in voltage and you could be right, but how would it fare in the scenario below?

Think of the output voltage of a crankshaft position sensor where the frequency (speed) of the signal will increase in proportion to engine speed. Using a multimeter to measure the voltage or frequency of this signal will only present you with an average voltage or frequency value. Should the crankshaft sensor be exposed to a deformed or missing tooth of a reluctor ring, the multimeter simply cannot display the momentary drop in voltage or frequency for the time period the missing tooth passes the tip of the crankshaft sensor. At idle speed this takes around 0.75 milliseconds to 1.5 milliseconds depending on design of the pick-up and frequency of the signal.

Connecting PicoScope to the vehicle and acquiring a signal does not have to be daunting or anything to fear. We have been doing this for years with our multimeter and the PicoScope connections are fundamentally the same. Simply requiring a signal (Supply) to be applied to one lead and a 0 V ground reference to the other (sound familiar?).

The scope most certainly has become an essential tool. Not only does it enable the technician to measure voltage, current, pressure and temperature against time, but allows the capture of event’s taking place at lightning speeds with incredible resolution ensuring nothing is missed during diagnosis.

Upcoming events and exhibitions

Vision KC The largest automotive service industry expo in the Midwest part of the United States, with most attendees saying it is the best show in the states, VisionKC is going on next month showcasing the latest in service related tools, equipment, products and services. Need some training on your PicoScope or just want to refresh your memory? Pico Technology will be exhibiting at the show, and there will be a hands-on PicoScope specific training course taking place. Covering the advanced features of PicoScope, and utilizing it with different Pico accessories such as our popular pressure transducer. We will also be highlighting the latest in the PicoScope 4000 series, so stop by booth number 233. 5th-8th March 2015 Vision KC Kansas City, MO USA
Motortec Automechanika Madrid Motortec Automechanika Madrid 2015, the Spanish edition of the World's Leading Trade Fair for the Automotive Industry catering for trade visitors from Spain and Portugal, Latin America and North Africa. The last show in 2013, welcomed over 41 000 sector professionals from 85 countries. A total of 469 companies from 20 countries took part in the fair. MIAC will be attending the show in 2015, and will showcasing Pico Technology's latest products; if you're attending the show why not visit them in hall 6C, stand 29. Motortec Automechanika Madrid 11th-14th March 2015 Madrid, Spain
Automotive Training Expo The 2015 Automotive Training Expo will have some of the best trainers from the industry lined up! Get the latest training, browse exhibits ranging from all aspects of the industry, benefit from great networking opportunities and more. Get inspired, get motivated and get informed! This is your chance to experience top industry-leading trainers speak. Great topics that are not only relevant to our industry and today's economy, but inspirational too. So don't miss out and "Mark Your Calendars" March 20-22,2015. Autonerdz will be representing Pico Technology at The West Coast's Largest Automotive Training Expo, why not stop by and see them at booth #51 Automotive Training Expo 20th-22nd March 2015 Doubletree Seattle Airport Hotel 18740 International Boulevard Seattle, WA 98188 USA
Automechanika Chicago Automechanika, known across the world as putting on some of the biggest automotive specific shows - has decided the states shouldn't be left out. This year, the brand is expanding and adding a location to the US. Automechanika Chicago, if judging by the other events they put on, will quickly become one of the must go to events for automotive tools and training. There will be scope training classes available as Pico Technology will be at the trade show in booth #1305, showing the latest scopes and accessories. Automechanika Chicago 24th-26th April, 2015 Chicago, IL USA