Steve Smith investigates a BMW 1 Series with a customer complaint of juddering at low speeds.
Technical description and road test
An extended road test at higher speed confirmed that the juddering stopped, but an additional "DTC" warning illuminated within the instrument panel.
The customer interview confirmed that the vehicle had full service history, no additional accessories installed and no recent repairs. The customer complaint was verified and the vehicle's identification and specification were confirmed.
The basic inspection confirmed visible ABS connections to be secure and the wheel and tire combination to be the correct specification for the vehicle. Tire wear, brand, orientation, condition and pressure were also inspected and confirmed to be correct. This is an overlooked fundamental inspection when diagnosing ABS and traction control faults. The ABS controller monitors the rate of acceleration and deceleration of wheel speed signals to determine if brake pressure intervention is required. Wheel speed signals vary depending upon tire circumference, and in scenarios where tire tread depths, styles and manufacturer differ, there is potential for tire circumferences to vary by 15 mm or more, resulting in differing wheel speeds during straight-line driving. Such a variation in wheel speed signals will have an adverse effect on brake control intervention.
In a perfect world all installed tires should be the same make and specification (and within the same construction date (stamped on the tire wall)) but in reality this is near impossible. We can, however, physically measure tire circumference and tread depths to confirm whether the deviation between tires is within manufacturer specification and eliminate these variables from our diagnosis.
A vehicle scan confirmed ABS fault codes, indicating signal plausibility and a possible concern surrounding the condition of the sensor pick-up (see code 5DC2 below "increment gear")...
To read on and see how Steve was able to correctly diagnose this fault, please see the BMW 1 Series case study on our website.
Pico and Frank Massey of ADS Limited have joined forces to bring you Frank's top ten tests with PicoScope.
In video #1, Frank discusses using PicoScope to observe voltage drop against load, measured as current by the consumer. Frank discusses the theory of the test, what is being tested and the simplicity of using a scope for this test. Timebases, voltage ranges, and of course the physical connections required are all covered.
WPS500X Maxi Kit
More information on the WPS500X Maxi Kit and its extensive list of parts can be found on our website.
Our Master Kit will be available later this month and will appear on our product kits page.
On the 1st July 2016, Pico Technology celebrates its 25th year of business.
Pico data loggers, oscilloscopes and signal generators are used by engineers, scientists and technicians around the globe to bring their products to market. Pico automotive diagnostics products help keep the wheels turning for vehicle manufacturers and service organizations on every continent.
1991 was an interesting year. Intel introduced the low-cost 486SX microprocessor, priced at $258. It was implemented on PCs running MS-DOS 5.0 and Windows 3.0. The World Wide Web Consortium was founded by Tim Berners-Lee at CERN, and the GSM mobile network was launched in Europe.
On 1st July Alan Tong and Mike Green co-founded Pico Technology. The company was originally set up as a software consultancy to develop data acquisition solutions using plug-in expansion cards, mostly for customers in the medical industry.
Pico, operating from Hardwick near Cambridge, introduced its first product, the ADC-10, so called because it was an analog to digital converter and sampled at 10 kS/s. It connected to the PC via the parallel port. The first order for ADC-10s was received in August that year, with two units sold for £49 each.
The ADC-10 was the world's first PC Oscilloscope, and in the years that followed Pico notched up several more industry firsts, including the first oscilloscope with digital triggering and the first high-resolution scope.
Today, Pico has over one hundred employees at its head office in St Neots, UK and its subsidiaries in the USA and Lithuania. The company has three divisions producing Test & Measurement, Automotive Diagnostics and Radio Frequency test products that are sold worldwide.
To read on, please visit the news section of our website.
Pico Technology is an exciting and innovative leader in the design of PC-based oscilloscopes and data acquisition technology. Our products include PC oscilloscopes, data loggers and automotive diagnostic equipment.
At Pico we believe that employing the right people is more important than fulfilling any specific vacancy, so if the right people are interested in working for us we will consider applications. We are particularly interested in applicants with a technical software background or experience of test equipment design.
If you want to be part of a growing company at the leading edge of test equipment design, why not take a look at our pico.jobs web page and see what we have to offer? We look forward to hearing from you.
Please visit Pico Exhibitions for the latest list of exhibitions and trade shows that Pico and its representatives will be attending.
Thanks to our continuing success and growth Pico are always seeking talented people to join our company.
Please visit http://pico.jobs/ to see our current vacancies. We look forward to hearing from you!
Our latest software releases are available as free downloads. To check which release you are using, start the software and select Help > About.
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Pico Technology, James House, Colmworth Business Park, St. Neots, Cambridgeshire, PE19 8YP, England
Tel.: 01480 396395 (+44 1480 396395)
Fax: 01480 396296 (+44 1480 396296)
Pico Technology North America Inc.
320 N Glenwood Blvd.
Tel:+1 800 591 2796 (Toll Free)
Fax:+1 620 272 0981
Web technical support: www.picotech.com/tech-support/