Retrieving Codes ADDITIONAL TESTS FOR EEC-IV SISTEMS Relay and Solenoid Test (Output State Check) The "Output State Check " is a special program in the vehicles computer that allows the user to energize (turn 0N) and de. energize (turn OFF). on command, most of the actumms. (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 energi'zpd during this test. 0 The Output Check Mode is activated immediately after the Key On Engine OiflKOEO) SelfTest is performed. 1. Perform the Key 0n 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 vehicles computer. NOTE: Ifynur vehicle is equipped with an Integrated Vehicle Speed Control, disconnect the vacuum supply liosr from the speed comm! 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 decoergize the actuators. press the accelerator pedal once and release. The square will disappear. indicating that the actuators are tie-energized, 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 tie-energize when performing the "Output State Check'K All applicable actuators should be on when energized and olf when (le- energized. Chapter 4 Retrieving Codes ADDITiOF-IAL TESTS FOR EECIV SVSTEMS . . "1"1e'e-C0mpuee' sends a voltage output signal W signal to energize the actuators. If an 1W is not responding to the Output State Check, Wt procedures described in the vehicle's sci-Vice '- - whim check computer actuator output circuit _ vameand/or grounds. E m performing the Output State Check, turn off the - ' hfgpi'oin and disconnect the Code Reader from the test aw oi-s. oymuiinalaooa Test Nehiclea equipped with Sequential Electronic Fuel Injected (SEFI) systems only) The Cylinder Balance Test assists in nding a weak or non~ wntpibnting cylinder. The computer shuts off fuel (cuts off r to injectors) to each cylinder, in sequence, and monitors for RPM changes (drop). Based on this information. the computer detennines if all the cylinders are contributing power equally (for proper engine operation I. or if some cylinders are only contributing partially or not contributing at all. SEFI Introduction Sequential Electronic Fuel Injection (SEFI) belongs to a family of fuel injection systems called "Multiport/Multipoint Fuel Injection". Multiport (MFD fuel injection systems contain one fuel injector .per cylinder. and the vehicle's computer electronically controls their operation. 011 some multiport fuel injection system. the Lquctors all fire at the some time and at every engine revolution. On other systems the injectors re in groups and/or at every other engine revolution. What distinguishes Sequential Electronic Fuel injection Systems From other multiport fuel injection systems is that each injector is independently energized and res sequentially (manner the other in the proper firing order. This gives the Vehicle computer more control to cut the fuel to one injector at a time kthis can't he nocomplished on the other systems because they re in groups of two or more injectors}. Thelcomputer can be put in "Cylinder Balance Test Mode by performing the KOER Self Test. waiting until all the KOER codes have been transmitted to the Code Reader, and then lightly taping the acceleralor (follow the Cylinder Balance Test procedures. on next page l. Chapter 4 40