Connecting Test Equipment and Reading Diagnostic Trouble Codes
Diagnostic Connection:
Testing with the impulse counter should be carried out for rapid fault diagnosis. The impulse counter output shows only existing faults, since the ACC system does not have memory capabilities. If one or more faults are indicated, repair as necessary and repeat the test. Be sure that fuse #7 is good, the battery voltage is between 11-14 volts and the temperature selector wheel is set to 22°C.
1. Connect the impulse counter to the on-board diagnostic connector.
^ Black lead of the impulse counter to socket 1
^ Yellow lead of the impulse counter to socket 7
^ Red lead of the impulse counter to battery positive terminal.
2. Turn the ignition to the "ON" position.
^ The LED "U Batt" will be illuminated. If the LED "U BATT" does not illuminate, check for voltage between socket 1 of the on-board diagnostic connector and the positive terminal of the battery. If the voltage is not between 11-14 volts, check for an open circuit or loose ground connection.
^ Test for voltage between socket 7 and socket 1 of the diagnostic connector. The voltage should be 6 - 12 volts.
3. Depress the start button for 2 - 4 seconds.
^ Fault codes will be indicated by the number in the impulse counter display window. Take note of the impulse display number.
^ Faults are displayed in ascending order.
^ The number 1 indicates that no faults are stored in memory.
^ During the impulse readout, The LED indicator in the fresh air/recirculation switch will blink.
4. Repeat step 3 until all faults are indicated. After all fault codes have been displayed, pushing the start button again for 2 - 4 seconds will repeat the fault code readout sequence.
IMPULSE (FAULT) DISPLAY RESULTS
^ Refer to the IMPULSE DISPLAY RESULTS, then proceed to DIAGNOSTIC CHARTS for specific diagnosis.
5. Repair the indicated faults. Be sure to turn the ignition switch to the "OFF" position before disconnecting connectors or components unless otherwise directed by testing procedures.