Fault Code ID & Sensor/Actuator Control - Task No 2 - Tuesday 24th February 2015

Oscilloscope

Autel Diagnostics Scanner

Date Start: 24th Feb 15

Time Start: 0900 hrs






Plan:

Gather vehicle information, tools and equipment required.  Check vehicle fluid levels and record battery voltage.  Undertake vehicle start to ensure prior proper operation. Connect Autel Diagnostics Scanner via vehicle DLC and interrogate ECU for existing DTCs.  Clear codes and re-run search, recording recurring codes on job card accordingly.  Analyse performance of following:

• Crank Angle Sensor Voltages (Pico).
• Throttle Position Switch Voltage Range (Pico)
• Ignition Timing from ECU at 2000 RPM (Live Data Autel)
• Fuel Pump Pressure (CI - Live Data Autel - 1600 Bar +) (SI - Fuel Pressure Test on Rail 2-4 Bar).

Produce drawings of all captured Picoscope images.  Record findings and analysis on job card. Report to Assessor for delivery of findings and recommendations. Account for all tools and equipment, tidy work area and write up Blog.

Task Progression:

Battery Voltage at Start:

Healthy Battery

Observation:  Washer Fluid Level Low.  Repair: Topped up to level required.

Retrieve DTCs:  Connected Autel Diagnostics Scanner and interrogated ECU for DTC's. One code returned (C1145 - OSF Wheel Speed Sensor Input Circuit Failure).  Cleared codes and re-ran search which produced no codes in return.

Analyse Crankshaft Sensor:  

Crank Shaft Sensor Location

The Sensor has 2 wires, indicating it is an inductive type (ie: requires a live feed).  Manufacturer's performance data indicated satisfactory operation between -4.0 V to +4 or 5 Volts.






Analysis:  Connected Picoscope as per the on board package instructions and conducted the test at Idle RPM.  The pattern returned indicated that the sensor was operating satisfactorily within the expected parameters.

Good Pattern Returned

Analyse Throttle Position Switch:  Manufacturer's Sensor performance data indicated satisfactory performance should be expected between the range of 0.5 or 1 V to 4 Volts.

Analysis:  Connected Picoscope as per the on board package instructions, probed the switch and actuated it to "Wide Open Throttle" and back again.  Captured image indicating satisfactory performance within the expected parameters.

Good Pattern Returned

Analysis Vehicle Ignition Timing From ECU at 2000 RPM

Autel Diagnostics Live Data Mode

Connected Autel Diagnostics Scanner via the on board DLC and accessed the Live Data Section.  Manufacturer's Data states satisfactory operation at approx 8-10 Degrees BTDC. Initial readings indicated 45 Degrees, however, as the engine warmed the readings settled to within satisfactory parameters.





Analyse Fuel Pressure SI Engine:  Manufacturer's Data indicated that Fuel Pressure should be in the region of 2 - 3 Bar on this SI engine.

Manufacturer's Data

Analysis:  Connected Fuel Pressure Test kit to Schrader Valve on Fuel Rail.  Turned ignition 2 clicks, in order to bring fuel to rail under pressure, and monitored pressure for approximately 30 minutes.  Pressure was low (at approx 0.5 Bar) but did not lose further pressure. Started engine and continued to monitor pressure, which raised a fraction, but insufficiently enough to meet expected satisfactory parameters.  This presented 4 scenarios, either Pump, Filter, Fuel Line or Diagnostic Equipment. With no obvious evidence of fuel leakage, recommend replacement of Fuel Filter (in-line type), and then re-run test to observe any improvement.



Repair:  In-line Fuel Filter replaced and test re-conducted.  Fuel Pressure now recording 2 Bar of pressure.

Analyse Fuel Pressure CI Engine:  When assessing Fuel Pressure on a CI Engine, pressures are invariably in excess of 1600 Bar, so for safety reasons, the test must be undertaken using a diagnostics device with a Live Data reading facility, such as the Autel Diagnostics Scanner.  For the engine being worked upon in this instance, expected satisfactory performance should be in the region of 1600 Bar.

Note also Unusual Cylinder Configuration

I then connected a Carman Diagnostics Scanner with Live Data reading facility via the on-board DLC to access the Fuel Pressure.  Having ensured the area was well ventilated I then started the engine and captured the fuel pressure information, which did not meet satisfactory parameters.  Pressure was reading Min 245 Bar, Maximum 360 Bar.

Diagnosis:

The most likely causes could be either Fuel Pump, Fuel Line, or Fuel Filter.  Recommend replacement of the Fuel Filter prior to commencing a further test to verify performance levels.