WS5 Scan Tool Diagnostics

Scan Tool Diagnostics


Make Honda                 Model Accord                                    Year 2004


1. Scan Tool Data

Type of information (PID = Parameter Identification)	Letter to describe it E.g. TPS	Value of data	Unit for data E.g. volts
Engine RPM	RPM	793	RPM
Engine Coolant temperature	ECT	91	C
Intake air temperature	IAT	65	C
Fuel Injection opining pulse	FI	2.41	ms
Vehicle Speed	VS	0	Km
Oxygen Sensors(S)	O2 (S)	0.6	V
Fuel Tim	Short long	1.02 0.99	%
Power Steering		0.05	V
Idle control	Ic	On
Air conditioning condition	A/C	On/off	C
Exhaust Gas Recirculation	EGR	0	lef
Fuel Evap or purge condition		no	%
Malfunction Indicatr light	MIL	YES
Bometric Pressure	Bp	8.5	Hz

Trouble Cods 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

Code number	System affected	Condition described
03 -02	MAP sensor	High voltage
10 - 02	IAT sensor	High voltage
06 - 02	ECT sensor	Current high input

5.2 Record the PIDs that have changed bellow

Type of information (PID= parameter identification)	Letters to describe it	Value of data	Using for data
Intake air temperature	IAT	16	C
Throttle position sensor	TPS	0.00	C
Manifold air pressure	MAP	110	kpa
Idle air control	IAC	1.20	V

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:

Disconnected the TPS sensors connection just found the problem.


7  Repair fault


7.1 Plug back in the connector, or repair problem found
7.2 Describe what you did :

Put them back in our plug


8. Recheck Data PIDs


8.1 Recheck the data with the scan tool
8.2 Record the voltage for the PIDs related to the problem, to confirm they are back to normal.

Type of information (pID=Parameter Identification)	Letter to describe it	Value of data	Units for data
Map Sensor	Map	102	Kpa
Idle Air Control	1AT	60	C
Engine coolant Temperature	ECT	90	C

9. Clear Codes
Describe what you did to clear codes :

We have to turn off the engine and put the disconnected plug, and start the engine, it will clear all codes. For this exercise the key should be on and engine should be off, and eraser the code on the scan tool.

10. Rechecks for codes and record codes in system now:


On recheck there is no codes on the scan tool.

11. Discuss the importance live data when full finding


We have to check the data when engine is running smoothly, and as good condition, so we can compare these data with faulty components data.

12. Explain the need for parameters when checking live data


They are very important to check the parameter in different conditions of the engine. Its for intake the engine load, how much air is coming in.

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


For findings faults the scan tool give us code number in type of information, PID wave of the scanner. I have found the scan tool to use easy than oscilloscope.

WS3 O2 Sensor

General Lab Scope


Make Toyota          Model 4A - EF


Signal Name O2 Sensor 
Volt/division/range 0.5 V
Time/division/range 25 ms


Draw the pattern below:

Explain the operation of the sensor or device using the Graph:
(Use arrow at different points, and describe what happens there)
Arrow B = When the engine run reach
Arrow C = When the engine is lean
Arrow D = Peak - maximum richness before gets lean
Arrow E = Peak - maximum lean before the engine start to get rich

WS3 RPM

General Scope


Signal Name RPM CAM dist 
Volt/division/range 2 V
Time/division/range 50 ms


Draw pattern bellow:

Explain the operation of the sensor or device using the Graph
(Use arrow different points, and describe what happens here)
This is analogue wave form A representing the cam sensor per each rotation of crank the piston is going 4 times is up and down as shown each graph.
Arrow 1 a magnetic field is created 
Arrow 2 magnetic field is collapsed and it is lowest.
Arrow 3 a magnetic field is creating
Arrow 4 sudden collapsing of magnetic field, and pulse is generated.

WS3 IAT

General Lab Scope


Signal Name IAT
Volt/division/range 2V
Time/division/range 10 ms


Draw the pattern below:

Explain the operation of the sensor or device using the Graph:
( Use arrows at different points, and describe what happens there)
Arrow A zero voltage 
Arrow B when the engine was cold voltage about 0.9 V 
Arrow C when the engine warmed up after zero second time the voltage was almost zero volt
Arrow D voltage continue dropping


Explain in detail an electrical fault that would make this operate incorrectly
If the IAT resistance is high, when the engine heated up it will have the return voltage signal wrong to the ECU. ie: The resistance drops as the temperature increase.


Explain why this condition would cause this unit to malfunction/Use mathematical equatios to back up your explanation
This unit will malfunction as resistance in high temperature is high and the return voltage signal is will be high too, therefore ECU reads this high voltage and determine the condition of the engine as cold.
Calculate : The ECU sends a reference voltage of 5 volts and gets the return voltage in represent to the voltage drop and then determine condition of the engine.
ie: If the variable resistor is R2 = 2500 ohms Ref V = 5 V
R1 = 1000 ohms then the total current I = V/R = 5/2500+1000 ohms = 0.0014 Amps
So the voltage drop will be V = IR = 3.5 V
Then the signal voltage is 5 - 3.5 = 1.5 V
therefore the ECU will determine the amount of fuel needed for the condition of the engine. If the resistance increase in the sensor ground side, then 3.5 V drop will .


Using the grah on the previous page (use different color) draw the pattern that this unit would give with this falt decrease as well so ths will effecthe function of the sensor and ECU will recive wrong sgnal and make wrong adjustment to PWM.


Explain how this condition would affect the operation of the vehicle?
On the graph not much changing because the engine was warmed .

WS3A ECT

General Lab Scope


Signal Name ECT
Voltage/division/range 2 V
Time/division/range 1ms

Draw the pattern below:

Explain the operation of sensor or device using the Graph:
(Use arrows at different points, and describe what happens there)

A = up to 2 V range about 2.1 V at the start.
B = Continuing the voltage dropping 
C = 1.9 V after 1 second 


Explain in detail an electrical fault that would make this unit operate incorrectly
Higher resistance will iscause higher voltage drop, which it gets from the ECU (5 V) will cause the wrong return voltage signal to the ECU.


Explain why this condition would cause this unit to malfunction/Use mathematical equations to back up your explanation.
As the temperature increase of the coolant resistance decrease, and the return voltage signal decrease to 5 v Ie: If the variable resistor R2 is 2500 ohms , and R1 in the PCM is 1000 ohms the total current I = V/R = 5v/3000 ohms =0.0014 Amps.
Therefore the voltage drop VD1 = IR = 0.0014 A*3500 ohms = 3.5 V in variable resistance , and the return voltage is 5 - 3.5 v = 1.5 V
If the resistance in sensor ground increase for example: 1000 ohms so the voltage drop at the resistor will be VD2 = IR   IT  = V/R = 5/4500 = 0.001 A and VD2 = IR = 0.001*1000 = 1V
VD1 = IR = 0.001*2500 =2.5V the voltage drop change i n variable resistor from 3.5V to 2.5V and the ECU will determine the PWM according to this wrong voltage of 2.5V


Using the graph on the previous page (use different color)  draw the pattern that this unit would give with this faulty (include the different points as with the previous pattern)
Explain how this condition would affect the operation of the vehicle?
The graph marked with M is a straight line  there is no change voltage drop , and the engine is in open loop, and urning rich, because he ECU fail to go into close loop. Once the engine is warmed up as it gets strong signal from the ECT because high resistance in the component.

WS3 A TPS

General Lab Scope


Make Toyota


Signal Name TSP
Volt/division/range 1V
Time/division/range 200 ms


Draw the pattern below:

Explain the operation of the sensor or device using the Graph:
(Use arrows at different points, and describe what happens there)

Arrow B = Represent at the idle voltage.
Arrow C = Where is the TSP opening and increase voltage.
Arrow D = Where the throttle body is wide open in this is the minimum voltage .
Arrow E = Where  the throttle body is closing and reduces the voltage.


Explain in detail an electrical fault that would make this unit operate incorrectly

Sludgation or dirt will effect the operation of this unit.


Explain why this condition would cause this unite to malfunction/ Use mathematical equations to back up your explanation.
The throttle body does not react to the voltage increase, because of the dirt and it stuck, and will not give the right voltage and ECU will get the wrong voltage reading and the engine may run rough (lean or reach) it will depend on the voltage.
Calculation:
If we have excessive voltage drop of the TPS to the ECU will not get a proper return voltage.
Ie: If variable resistor is 1K ohms and the resistance in PCM is 1000 ohms then the total current will be:
V=5 V
IT = V/R = 5/2000 ohms = 0.0025 A
The voltage drop in variable resistor is:
V = IR = 0.0025A *1000 = 2.5 V
This is the signal voltage the ECU, will get. If there is excessive voltage drop due to dirt, bad earth, this 2.5 V drop will decrease and the ECU will get wrong signal.

Explain how this condition would affect the operation of the vehicle?
As we open the throttle, the voltage increases accordingly, but if there is bad sensor if will drop in voltage .

WS3A MAP

General Lab Scope


Make Honda      Model Accord      Year 2004

Signal Name MAP Analogue 
Volt/division/ range  2 V
Time/division/range 1 second


Draw the pattern below:

Explain the operation of the sensor or device using the graph:
(use arrows different points, and describe what happens there)

Arrow A = Idle
Arrow B = Acceleration high voltage, and low vacuum.
Arrow C = Accelerating .
Arrow D = Keep open the throttle for the intake air.
Arrow E = Deceleration


Explain in detail an electrical fault that would make this unit operate incorrectly

Vacuum leaks in the intake manifold or house that connect the sensor to the engine


Explain why this condition would cause this unite to malfunction
 A vacuum leaks will reduce intake vacuum and cause this unit to indicate a higher than normal load on the engine