flash codes

i used my toyota cynos 1991 for this practical and my tutor provided the manual with the flash codes. my tutor created a fault in the engine and using the check engine light flashes as an indicator i was to find the problem and fix it. the check engine light should remain on when the car is turned on and engine not running.
once engine is started and the check engine light remains on, the diagnosis system has detected and error in the system.
I opened the diagnostic plug located under the bonnet and jumped/bridged terminals E1 and TE1. Using the table below as reference, the fault code was 31( the check light flashed 3 times then 1 time).this means the was an error in the vacuum sensor circuit.My tutor had unplugged it. i pushed it back in and cleared the fault code by disconnecting the battery negative terminal for half a minute. The check engine light did not come on so i had diagnosed the fault.

Diagnostic Fault Codes

Fault Code	Item
1	Normal
2	Vacuum Sensor Signal
3	Ignition Signal
4	Water Temperature Signal
6	RPM Signal
7	Throttle Position Sensor
8	Intake Air Temperature
9	Vehicle Speed Sensor
10	Starter Signal
11	Air Conditioner Switch
12	G, NE Signal Circuit
13	NE Signal Circuit
14	Ignition Circuit
16	ECT Control Signal
21	Oxygen Sensor Circuit
22	Water Temperature Circuit
24	Intake Air Temperature Circuit
25	Air – Fuel Ratio Lean Malfunction
31	Vacuum Sensor Circuit
33	Idle Speed Control System
41	Throttle Position Sensor Circuit