Output Diagnostic Test Mode (Circuit Actuation Tests)

This mode is used to turn a specific circuit on and off in order to check it. ATM test codes are used in this mode.

1. Put the system into the diagnostic test mode and wait for 55 to appear on the readout box display.
2. Press and hold the ATM button on the readout box until the desired ATM test code appears on the display and then release the button.
3. The computer will turn the selected circuit on and off at 250 milliseconds intervals for 5 minutes and then turn the test off. To stop the test before the 5 minute period, turn the ignition switch off.

CIRCUIT ACTUATOR TEST CODES

Code 91 - Indicates that the oxygen feedback solenoid is activated.
Code 92 - Indicates that the shift indicator light on manual transmission equipped vehicles or transmission unlock relay on automatic transmission equipped vehicles is activated.
Code 93 - On 4-135 engines, indicates that the vacuum operated secondary solenoid is activated.
- On 6-225 and V8-318 engines, indicates that the air switching solenoid is activated.
Code 96 - Indicates that the fan relay is activated.
Code 97 - Indicates that the electronic throttle control solenoid is activated.
Code 98 - Indicates that the vacuum operated secondary control solenoid is activated.