Retrieving Codes 4 ADDITIONAL TESTS FOR EEC-IV SYSTEMS Relay and Solenoid Test (Output State Check) The "Output State Check " is a special program in the vehicle's computer that allows the user to energize (turn ON) and de- energize (turn OFF), on command, most of the actuators (relays and solenoids) that are controlled by the computer. 0 Use this test to check computer output voltages and relay/solenoid operation. NOTE: The fuel injectors and fuel pump are not energized during this test. 0 The Output Check Mode is activated immediately after the Key On Engine Off (KOEO) Self Test is performed. 1. Perform the Key On Engine Off (KOEO) Self Test, steps 1 through 11 (refer to page 25 for procedures). 2. Wait until the Code Reader retrieves all the KOEO Self Test and Continuous Memory codes. I The ashing square icon no longer appears on the display when all the codes have been retrieved. 3. Immediately after all Continuous Memory codes have been retrieved, step on the accelerator pedal once, then release. This activates the Output State Check and energizes most of the actuators (relays and solenoids) that are controlled by the vehicle's computer. NOTE: If your vehicle is equipped with an Integrated Vehicle Speed Control, disconnect the vacuum supply hose from the speed control servo before pressing the accelerator. Reconnect vacuum hose after test. I The square icon will appear and stays on solid 'on the right hand side of the code reader's display to indicate that the Actuators are energized. 4. To de-energize the actuators, press the accelerator pedal once and release. The square will disappear, indicating that the actuators are de-energized. I I The procedure can be repeated as many times as desired by pressing and releasing the accelerator pedal to energize and de-energize the Actuators. 5. Consult the vehicle's service manual for a list of all the actuators (solenoids and relays) controlled by the computer that apply to the vehicle under test, and which actuators should energize and de-energize when performing the "Output State Check". All applicable actuators should be on when energized and off when de- energized. 39 Chapter 4 Retrieving Codes ADDITIONAL TESTS FOR EEC-IV SYSTEMS I The vehicles computer sends a voltage output signal or a ground signal to energize the actuators. If an actuator is not responding to the Output State Check, follow the procedures described in the vehicle's service manual to check computer actuator output circuit voltages and/or grounds. .. Alter performing the Output State Check, turn off the ignition and disconnect the Code Reader from the test connectors. Evil!!! Illlnce Test r (Vehicles equipped with Sequential Electronic Fuel Injected (SEFI) systems only) The Cylinder Balance Test assists in nding a weak or non- vontributing cylinder. The computer shuts off fuel (cuts off power to injectors) to each cylinder, in sequence, and monitors for RPM changes (drop). Based on this information, the muuputer determines if all the cylinders are contributing power mumlly (for proper engine operation), or if some cylinders are only contributing partially or not contributing at all. HICFI Introduction Hoquontial Electronic Fuel Injection (SEFI) belongs to a family of fuel injection systems called "Multiport/Multipoint Fuel initiation". Multiport (MFI) fuel injection systems contain one fuel injector per cylinder, and the vehicle's computer electronically controls their operation. On some multiport fuel injection system, the injectors all fire at the same time and at every engine revolution. On other systems the injectors re in groups and/or at every other engine revolution. Wimt distinguishes Sequential Electronic Fuel Injection nyutoms from other multiport fuel injection systems is that each injector is independently energized and res sequentially mo alter the other in the proper ring order. This gives the vehicle computer more control to cut the fuel to one injector at n time (this can't be accomplished on the other systems imcnusc they re in groups of two or more injectors). The computer can be put in "Cylinder Balance Test Mode" by pnrihrming the KOER Self Test, waiting until all the KOER rmhm have been transmitted to the Code Reader, and then iiuhtl y taping the accelerator (follow the Cylinder Balance Test procedures, on next page). ' Ohlphr 4 - 40