How to Use the Diagnostic Readout Box

The diagnostic readout box is used to put the system into a Diagnostic Test Mode, Circuit Actuation Test Mode, Switch Test Mode, Sensor Test Mode and Engine Running Test Mode.
The following is a description and how to use each test mode:

1. DIAGNOSTIC TEST MODE-This mode is used to see if there are any fault codes stored in the on-board diagnostic system memory.
a. Connect the tool to the mating connector located in the wiring harness by the right front shock tower.
b. Place the read/hold switch on the readout box in the READ position.
c. Turn the ignition switch on-off, on-off, on within 5 seconds.
d. Record all codes. NOTE: You may stop the displaying of codes by moving the read/hold switch to the hold position. Returning to the read position will continue the displaying of codes.

2. CIRCUIT ACTUATION TEST MODE (ATM TEST)-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.
a. Put the system into the diagnostic test mode and wait for 55 to appear on the readout box display and make sure the read/hold switch is in the READ position.
b. 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.
The logic module will turn the selected circuit on and off at 2 second intervals for 5 minutes and then turn the test off. To stop the test before the 5 minute period, turn the ignition switch off.

3. SWITCH TEST MODE-This mode is used to determine if specific switch inputs are being received by the logic module.
a. Make sure all the switches that send an input to the logic module are turned off.
b. Put the system into the diagnostic test mode and wait for 55 to appear on the readout box display and power loss/limit lamp to stop blinking.
c. Turn on the desired switch for input into the logic module.
If the input is received by the logic module the display will change when the switch is turned on and then change again when the switch is turned off.

4. SENSOR TEST MODE-This mode is used to see the output signals of certain sensors as received by the logic module. Sensor access codes are used in this mode.
a. Put the system into the actuation test mode (ATM).
b. Press and hold the ATM button until the desired sensor access code appears on the display and then release the button.
c. Move the read/hold switch to the HOLD position. NOTE: Since sensor access codes are the same as some ATM test codes, the ATM test circuit will turn on before moving the read/hold switch to the hold position.
d. The logic module will now use the readout box to display the output of the selected sensor. All readings displayed are to be divided by 10 except the coolant sensor which is to be multiplied by 10. Battery voltage is actual and no correction is required.

5. ENGINE RUNNING TEST MODE-This mode is used to determine if the oxygen feedback system is switching from rich to lean and lean to rich and if the automatic idle speed motor and detonation systems are operational.
a. Connect tool to the mating connector in the wiring harness by the right front shock tower. Make sure the read/hold switch is in the read position.
b. Start the engine and observe the display of the readout box. When the oxygen sensor is at operating temperature the display will show you if the oxygen system is switching rich/lean by alternately displaying 0 and 1 (0=lean, 1=rich) when in closed loop. When the engine is running in neutral or park the idle motor system can be checked by moving the read/hold switch to the hold position. Engine speed should increase to approximaately 1500 RPM. With engine speed above 1500 RPM, an 8 will appear next to the 0 or 1 when the detonation sensor is working.