Emissions Practice Task - Monday 5th January 2015

Diagnostics Scanner
Connected

Today saw the resumption of activities after a 2 week Winter Stand Down, and it was straight back to work with the Emissions Practice Task.  This required the use of a Diagnostics Scanner for the detection of DTC's and also a Picoscope, to obtain patterns of a Zirconia Lambda Sensor, a Throttle Switch and the Throttle Potentiometer Switch at the accelerator pedal.  The vehicle being worked upon was a Ford Fiesta 1.25.  Having undertaken the planning process, gathered and set up all the equipment needed and carried out pre-inspection vehicle checks, we commenced by connecting the Autel Diagnostics Scanner to the vehicle DLC and began the search for DTC's accordingly.  After several attempts we were repeatedly presented with a message informing us that there was an issue with communications. We changed to the Carman Scanner and got the same result, at which point we decided to call in Steve Leonard who began to investigate further, but due to "pie break time", we were informed to resume afterwards.  Upon returning we called in Julian Jones for guidance (and with Marshal Clayton now in attendance also by chance!) both suggested it was the DLC probably at fault.  With a firm hold on the DLC the scanner operated sufficiently long enough to retrieve some codes for faults, set by Julian, whilst we stood away in the "naughty corner" with instructions not to peek whilst he did so"!  With our findings recorded on the job card and lessons learned, we moved swiftly onto the Picoscope to obtain patterns of the Lamda Sensor.  Having warmed the engine to operating temperature, the pattern subsequently returned was nothing like the example of the one shown within the Picoscope package, so we immediately knew there was an issue with the sensor.

Pattern Obtained from Fiesta Zirconia Sensor

Example of Good Pattern

Sensor
Continuity Test

 At this point I suggested we disconnect the sensor connector and test for continuity using a multimeter.  The sensor was probed across both the black and grey wires and also the 2 white heater wires, and in both cases a negative result was recorded.  Our minds were almost already made up, but with the lessons of earlier still ringing loud, we went on to conduct the same test using the Picoscope on the resident Volvo S40, which is a known good one.  Having started the Volvo we were observed as having not undertaken the pre-cursory vehicle checks and duly back-tracked to find the oil level low, and also evidence of emulsification on the inside of the filler cap (lesson learned again).  Julian subsequently authorised a change of engine oil, at which point Isaac was dispatched for 5 litres of engine oil from Workshop A/B whilst I made ready the floor crawler and a drain pan for his return, and also warmed the oil ready for dropping.

Oil Drain

Filtered Zirconia Sensor Pattern of Volvo S40

With the oil drained and inspected for further evidence of contamination, all was given a thumbs up for the re-fitting of the drain plug and the subsequent re-filling of fresh engine oil to Autodata specification.  We then resumed the Picoscope test on the Volvo's Lambda sensor which further confirmed our suspicion regarding that of the Fiesta's, and our findings were duly recorded on our job cards accordingly.  With our patterns reproduced as drawings as evidence, we then had our cards signed off to the point of current task advancement, as the end of session was rapidly approaching.  The task resumes tomorrow with the final two Picoscope tests on the Fiesta of the Throttle switch and Potentiometer.  A very challenging and rewarding day indeed, and I felt we worked extremely well together throughout.  Nighty night and thank you!