WS5    Scan Tool Diagnostics

Make: Toyota  Model: Sprinter Year: 1987

(Course: using a Scan Tool that communicates to the engine you want to test.)

Warning: Be careful working around engines and exercise caution to avoid injury.

1. Scan Tool Data

1.1        Find a vehicle which is appropriate for the scan tool.

1.2        Connect the scanner, power it on, follow the instructions and input the correct vehicle information it asks for so you can view the data.

1.3        Find the data for the information listed on the next page. Turn engine on to idle. Fill in the letters used to label the information and the value of that data. (For example, engine load information may be found under MAP, with a value of 3.6, listed in volts) Note: not all vehicles will support all information, just find as much as you can. If the engine won’t run, input the information with the key on, engine off.

Type of information (PID = Parameter Identification)	Letters to describe it E.g. TPS	Value of data	Units for data E.g. volts
Engine Load (how much air comes in)	Intake	29	kpa
Engine RPM	RPM	800	RPM
Throttle angle	TPS	0	%
Engine coolant temperature	ECT	85	degree
Intake air temperature	N/A	N/A	N/A
Fuel Injection opening pulse	FIOP	2	ms
Transmission select position	N/A	N/A	N/A
Vehicle Speed	N/A	0	km/h
Oxygen sensor(s)	N/A	LEAN RICH	N/A
Fuel Trim	N/A	N/A	N/A
Idle control	ISC	39	%
Power steering condition	N/A	N/A	N/A
Air conditioning condition	A/C Signal	off	switch on/off
Exhaust Gas Recirculation (EGR)	N/A	N/A	N/A
Fuel Evap or Purge condition	N/A	N/A	N/A
Malfunction Indicator Light (MIL)	N/A	N/A	N/A
Barometric Pressure	N/A	N/A	N/A

2              Trouble Codes or Fault Codes

2.1        Find where the Codes are listed

 

2.2        Record any codes, and what system and condition they describe in the chart below (Example: might be code number 21, for Throttle Position Sensor, signal voltage too low) If there are no codes listed, put “none”.

Code number	System affected	Condition described
No Code

3              Lecturer put in Fault

3.1        Find your lecturer and have him create a fault under the hood (don’t look)

4              Record New Codes

4.1        Look up the codes now in the scan tool

4.2        Record the codes in the chart below. Also record what system is affected, and what condition is described.

Code number	System affected	Condition described
31	Air flow meter / VAC sensor	Engine stop
22	Coolant Temperature Sensor	No signal, the ECU orders a rich mixture all the time therefore, the engine RPM goes up.

5              Find What Data Has Changed

5.1        Look through the scan tool data to see what PIDs (Parameter Identification of system voltages) have changed. Which readings don’t make sense or don’t read what you would expect. Concentrate on the PIDs related to the codes.

5.2        Record the PIDs that have changed below:

Type of information (PID = Parameter Identification)	Letters to describe it	Value of data	Units for data
Engine speed	RPM	875	RPM
Coolant Temperature Sensor	CTS	90	degree c
Intake Manifold	Intake Manfold	46	kPa

6              Visual Inspection to find fault

6.1        Do a visual inspection under the hood to find where the problem is. Use information from the code to know where to look for the problem and what type of problem to look for.

Describe problem you found:

When the Engine Vacuum sensor is disconnected, the engine is not running

7              Repair fault

7.1        Plug back in the connector, or repair problem found

7.2        Describe what you did:


I re-connected the vacuum sensor and restarted the engine. The engine ran good without any problems.


8              Recheck Data PIDs

8.1        Recheck the data with the scan tool

8.2        Record the voltages for the PIDs related to the problem, to confirm they are back to normal

Type of information (PID = Parameter Identification)	Letters to describe it	Value of data	Units for data
Engine Speed	RPM	825	RPM
Engine Coolant Temperature Sensor	CTS	90	°C
Intake Manifold	Intake Manifold	27	KPa

9              Clear Codes 

Describe what you did to clear codes:


I disconnected the battery negative cable for 30 seconds then reconnected it. 

           

                       
10          Recheck for codes and record codes in system now:
         There were no trouble codes detected when I selected the D.T.C button on the tool. 

11          Discuss the importance live data when fault finding:
        Live data allows me to see the values of all the sensors on the vehicle on one screen. 

                 

12          Explain the need for parameters when checking live data:


when the fault is resolved, the live data will be rechecked with its parameters then the data should be compared to fault datas.            

                       
13     Discuss how a scan tool can aid you when fault finding

          A scan tool can display all the values of the different types of sensors on a variety of different vehicles. This makes it easier to locate faults. 

                        

WS7 Exhaust Gas Analysis (Petrol only)

Make: Toyota  Model: Corsa Year: 1996

Exhaust Analyser should be warmed up and recently calibrated. When it’s time to start taking tailpipe readings, put the analyser probe into the tailpipe and install exhaust tube over probe to capture exhaust fumes. Make sure there is adequate ventilation.

Note: make sure you fill out the “means: ........  segment to explain what that gas reading means. Example, if you are measuring HC, which shows us about misfire in the engine, and you had a low number like 28 ppm, you would say “shows low amount of misfire”, or “most of the fuel is being burnt.” But if the HC was high, like 340 ppm, you might say “There is a high amount of misfire” or “not all the fuel is being burnt.”

1.         With the analyser probe sensing normal air, what are the Four Gas readings? Record the amount and then what it means:

CO: 0.001% means: Carbon monoxide which indicates rich air/fuel mixtures. CO is a byproduct of combustion, therefore, if combustion does not take place, carbon monoxide will not be created. If high CO is measured then too much fuel is being delivered to the engine for the amount of air entering the intake manifold.  

HC: 12ppm means: Hydro Carbon which is unburned fuel that remains as a result of a misfire. When combustion doesn't take place or when only part of the air/fuel charge burns, hydrocarbon levels goes up. 

CO2: 0.00% means: Carbon Dioxide is a desirable byproduct that is produced when the carbon from the fuel is fully oxidized during the combustion process. As a general rule, the higher the carbon dioxide reading, the more efficient the engine is operating. 

O2: 20.9% means: Oxygen indicates a lean running engine since O2 increases with leaner air/fuel mixtures. 


2.         Start the engine idling cold, and record the Four Gas readings

Explain what is happening within the engine referring to the four gases:  

CO: 2.5%  HC: 788ppm  CO2: 12.6% O2: 5.15% 


The CO reading of 2.5% shows that there is a high amount of fuel being delivered to the engine for the amount of air entering the intake manifold. This is because the engine is cold. There is high amount of HC which means not all the fuel is being burnt inside the engine or because the catalytic convertor has not reached operating temperature. The CO2 shows that there is a low amount of misfires and that the engine is running efficient. The 02 readings show that there is a lean air/fuel mixture.

  

 3.    When the engine has warmed up, record the Four Gas readings:

Explain what is happening within the engine referring to the four gases:    

CO: 0.50% HC: 235ppm CO2: 14.2% O2: 1.10%


CO shows.. HC shows that most of the fuel is being burnt. CO2 shows that the carbon from the fuel is fully oxidized during combustion therefore misfires are low and the engine is running efficient. There is a low amount of O2 produced from the engine which shows that the air/fuel ratio is gone rich of stoichiometry. 

4.    Run the warm engine at 2500 RPM, record the Four Gas readings:

Explain what is happening within the engine referring to the four gases:    

CO: 0.234% HC: 121ppm CO2: 15.10%  O2: 0.32%


HC shows most of the fuel is being burnt. 

5.         At idle, run the mixture rich with extra propane, LPG, or carburettor cleaner,  and record the Four Gas readings:

Explain what is happening within the engine referring to the four gases:    

CO: 0.961% HC: 224ppm CO2: 14.32% O2: 8.68%

6.    At idle, create a lean condition with an air leak or vacuum leak, record the Four Gas readings:     

    Explain what is happening within the engine referring to the four gases:         

CO: 0.029% HC: 470ppm CO2: 7.79% O2: 5.93%  

7.    Accelerate the engine, by blipping the throttle a few times (don’t rev too high anddamage the engine), and watch how the gas readings change.  Record the Four Gas readings when the CO is highest: 

    Explain what is happening within the engine referring to the four gases:         

CO: HC: CO2: O2:

8.    Disconnect one spark plug wire, ground it with a jumper wire, then record the Four Gas readings as the engine idles:

     Explain what is happening within the engine referring to the four gases:         

CO: 0.01 HC: 1033ppm CO2: 13.6% O2: 4.53% 


The cylinder that the spark plug wire got grounded to could not ignite the fuel in the combustion chamber because it was grounded to the cylinder head. This caused that cylinder to misfire and not burn the fuel that was injected and the air that entered the combustion chamber. As a result the HC ppm levels were as high as 1033ppm which is because there was 1 cylinder misfiring every four strokes and so waste alot of gas and oxygen. 

9.    If you can get to it, disconnect the injector harness connector from one injector on an engine that has one injector for every cylinder: Record the Four Gas readings as the engine idles:

Explain what is happening within the engine referring to the four gases:    

CO: 0.009% HC: 53ppm CO2: 11.61% O2: 5.45%


The engine is running lean. One injector is disconnected and so in that cylinder on the intake stroke only air is entering the combustion chamber. O2 levels are high because it is not being mixed with fuel and burnt in the cylinder with the missing injector. 

10. Optional: Make other changes to the engine at idle, such as turning on the air conditioning or rocking the steering wheel.  Note the change you made: 

    Explain what is happening within the engine referring to the four gases:         

CO: 0.009% HC: 18ppm CO2: 15.44% O2: 0.04%   

Return the vehicle to good condition and proper adjustment.

11.      Explain the different readings you would get from a vehicle with a catalytic converter and a vehicle without one and why?


A vehicle with a catalytic convertor converts harmful HC + CO + NOx into harmless compounds such as H2o, CO2 and N2. A vehicle without one may only reduce some compounds like NOX levels using an EGR valve. But a vehicle without a catalytic convertor does not reduce as much emissions as a vehicle with one does.  

12.      Explain what light off point means and what happens?


Light off point is when the catalytic convertor has reached its operating temperature and starts to reduce emissions 

13.        On lambda, 02 sensors why do they have 1,2,3,4 or 5 wires and what do these extra wires do?
They have 2 white wires which are heater + and heater - which heat the sensor to get it up to operating temperature so it responds quicker. The 3rd wire is black wire which is a signal wire to the ECU which tells it how much free o2 there is in the exhaust gases. The 4th wire is grey which is the signal earth wire.