WS5 SCAN TOOL DIAGNOSATICS

Toyota Corolla 2002 1ZZ-FE engine was used for scan tool experiment with Hanatec.

There is a table of life data below:

Type of information(PID=Parameter Identification)	Letters to describe it	Value of data	Units for data
Engine Load(how much air comes in)	AFM(MAF)	2.58	Gm/s
Engine RPM	Engine speed	700	RPM
Throttle angle	Throttle position	11	%
Engine coolant temperature	Coolant temperature	71	C
Intake air temperature	Intake air temperature	22	C
Fuel Injection opening pulse	Injector pulse width	2.7	ms
Transmission select position	shift	4
Vehicle speed	0	0	Km/h
Oxygen sensor(s)	O2 sensor B1 S1	0.890	V
Fuel Trim	Short fuel trim#1	-20.3	%
Idle control	IAC duty ratio	37.5	%
Power steering condition	PS	off
Air Conditioning condition	A/C cut signal	on
Exhaust Gas Recirculation(EGR)	-	-	-
Fuel Evap or Purge condition	EVAP VCV	OFF	-
Malfunction Indicator Light	Warning light/MIL	on	on

Trouble codes were registered are in the table

 

Code Number	System affected	Condition described
PO753	Shift solenoid #1	Circuit malfunction
PO758	Shift solenoid #2	Circuit malfunction
PO758	Shift solenoid B	Electrical
PO773	Shift solenoid SL	Circuit malfunction
PO773	Shift solenoid E	Electrical
P1760	Shift solenoid VLAVESI/SLT	Circuit malfunction
B2798	Communication malfunction	#2

N.B. We’ve considered that all this data is related with preinstalled information when the stand was assembled.  So that, it doesn’t affect our test.

Our fault was related with TPS circuit

Code number PO120 TPS Circuit Malfunction

PO120 Throttle position 0 %

To find a fault we acted as follows:

Voltage drop on the ground side didn’t revile any problem. Signal wire was operating. But reference voltage was out of spec. That’s how we concluded that the fault was voltage reference circuit. Next step was to check 5V supply wire from the ECU.

 As it shown on the photo above, to erase codes you must follow the instruction you are given on the screen.

The experiment lighted up that data reading based on the sound technician knowledge of all engine parameters helps to localise fault quite quickly. Moreover, in many cases scantool is the only equipment which allows cleaning the data and so far returning the engine ECU module to the normal working condition.

Bearing in mind that modern ECU modules have adaptive learning function, technician must be accurate with understanding how to operate with all the data, short-term fuel trim and long-term fuel trim. These skills are very useful and worthwhile.