Flash Codes

Make: Toyota Model: Corolla 4A Year:  2001

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

Note: The engine check light must be working for these test.

1. Flash/Blink Codes

1.1          Find a engine/vehicle that you have the workshop manual with the correct procedure and codes to diagnose the flash codes

Create a fault- unplug something

1.2          Using the workshop manual follow the procedure to extract the codes, explain briefly what is the procedure

 

Open the bonnet, locate the diagnostic connector,

Turn the Ignition Switch ON.

Open the Diagnostic Plug

Using a “Jumper Wire” or paper clip connect terminals “TE1” and “E1”

Read the Fault Code

2              Trouble Codes or Fault Codes

2.1          The Codes are listed in the Toyota 4AFE book.        For example;

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

 

2.3          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)

 

Code number	System affected	Condition described
12	G, NE Signal Circuit	Unpluged
22	Water Temperature Circuit	Unpluged
31	Vacuum Sensor Circuit	Unpluged
22	Water Temperature Circuit	Unpluged

3              Visual Inspection to find fault

3.1          Do a visual inspection under the bonnet 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.

3.2          Describe the problem(s) you found:  Unpluged sensor connections

4              Repair fault

4.1          Plug back in the connector, or repair problem found

Describe what you did: pluged in the connectors for the sensors

5              Clear Codes 

Describe what you did to clear the codes:

I removed the negative battery connection for at least 30 seconds

6              Recheck for codes and record codes in system now: none

7              How could the faults found affect the engine performance?

           

The engine was difficult to start and ran with RPM dropped by 200 RPM, also the cooling circuit is operating in open loop mode/ no feedback

8              Other tests that  should be done once you have found the fault codes are to check the sensors output and the related circuit.