Without Scan Tool

When problems occur in ECU monitored input or output devices, the dash mounted malfunction indicator lamp (MIL) will light ("CHECK"), and stay "ON" while faults are present and the engine is running. Codes are stored in the computer memory that identify the faulty circuit or component. The following describes the procedure for displaying codes stored in the self diagnostic memory.

During this test procedure, the ECU will display input and output device failure codes by flashing the MIL lamp on the instrument panel.

NOTE: The ECU continuously checks for input device malfunctions. However, it only checks for output device malfunctions during a 3 second period after the ignition switch is turned "ON" with test connector grounded. If more than one failure code is present, the lowest number code is displayed first. Subsequent codes are displayed in numerical order.


READING THE CODE CYCLE
CODE CYCLE BREAK

Malfunction Code Cycle Break:

Time between warning code cycles is 4.0 seconds (time light is "OFF").


SECOND DIGIT OF MALFUNCTION CODE (ONES POSITION)

Malfunction Code (Ones Position):

Digits in ones position of warning code represent the number of times light is "ON" 0.4 seconds during one cycle.


FIRST DIGIT OF WARNING CODE

Malfunction Code (Tens Position):

Digits in tens position of warning code represent the number of times light is "ON" 1.2 seconds during one cycle.
The light goes "OFF" for 1.6 seconds between its long and short pulses.


INSPECTION PROCEDURE
1. Warm engine to operating temperature and switch ignition "OFF."

Diagnosis Connector:

2. Bridge the "TEN" and "GND" terminals of the diagnostic connector.
3. Turn ignition switch "ON."
4. If the MIL lamp illuminates ("CHECK") for approximately 3 seconds and then goes "OFF" and stays "OFF," no codes are present.
5. If the MIL lamp illuminates ("CHECK"), goes "OFF" and then starts flashing, codes are present.
6. Start the engine and check for additional codes.
7. If codes are present, note code numbers and check for causes.
Diagnostic Trouble Code Descriptions