Ignition

Diagnostic Socket Location:

PURPOSE AND LOCATION
The ignition ECU has a self diagnostic and function test system. These are combined with the diagnostic and function test system of the fuel injection ECU.
The diagnostic system of the ignition ECU is capable of detecting 6 faults and storing three different codes (California vehicles can store all 6 fault codes) in its memory. The ECU continuously monitors the following functions during driving:

^ Control unit internal functions
^ Knock sensor signal
^ Coolant temperature sensor
^ Throttle switch
^ Engine speed and position signal
^ Air mass meter signal

To check the fault code memory or a component, you must access the diagnostic socket located in the engine compartment behind the left suspension tower.

Diagnostic Socket Description:

FUNCTION
This diagnostic socket is used for communication with the diagnostic functions in the ignition and fuel injection ECU.
The diagnostic socket consists of a button, an LED and a selector cable. For fault tracing on the ignition system, the selector cable is placed in output #6. By pressing the button once, twice or three times (depending on control function required), the ignition ECU is accessed.

Control function #1:
This control function will access the ignition ECU memory and extract any recorded faults.
Faults stored in the ECU are read via "fault codes" consisting of flashes at the LED.

Control function #2:
This is a function test of the throttle position signal (sensor) in the ignition system.

Control function #3:
This function is used with the engine stopped. Selected output components are automatically tested and activated to check for correct operation.

For more information on how to operate all the functions in the diagnostic socket see DIAGNOSIS AND TESTING PROCEDURES.