1994 MAZDA MX-5 sensor

F EXHAUST GAS RECIRCULATION (EGR) VACUUM PUMP EGR SOLENOID VALVE (VENT) lnspection 1. Disconnect the vacuum hoses. 2. Blow through the EGR solenoid valve (vent) and verify u that air flows. 3. Disconnect the EGR solenoid valve (vent) connector. 4. Apply battery positive voltage and a ground to the EGR solenoid valve (vent) as shown. 5. Blow into the EGR solenoid valve (vent) and verify that air does not flow. 6. If not as specified, replace the EGR solenoid valve (vent) assembly. EGR FUNCTION SENSOR lnspection Output voltage inspection 1. Disconnect the PCME connector. 2. Connect the SST to the PCME as shown and connect a vacuum pump. 3. Turn the ignition switch to ON (engine OFF). 4. Measure voltage at the terminals as shown in the table. I I Vacuum I Terminal 5. If not correct at terminal 2J, check the wiring harness and 'i terminal 21 of the PCME. B A C Resistance 1. Disconnect the EGR function sensor connector, and connect an ohmmeter. 2. Disconnect the vacuum hose from the EGR control valve, and connect a vacuum pump. 3. Measure the resistance between the terminals as shown while vacuum is applied. PCME Specification 2K 2 D 2J Approx. 0 kPa {O mmHg, 0 inHg} 4. If not as specified, replace the EGR control valve. Approx. 20 kPa I150 mmHg, 5.9 inHg} 4.5--5.5 V OV Terminal LC A-C A-B Approx. 0.8 V Resistance 0.1-2.4 ki2 0.5-2.7 W1 Approx. 2.7 W1 Approx. 5 V Gartner Banana

EXHAUST GAS RECIRCULATION (EGR) EGR CONTROL VALVE I EGR CONTROL VALVE Inspection 1. Start the engine and let it idle. 2. Connect a vacuum pump as shown and apply vacuum. 3. Verify that the engine runs roughly or stalls at more than the specified vacuum. Specification: 5.4--12.0 kPa (40-90 mmHg, 1.6-3.5 inHg) 4. If not as specified, replace the EGR control valve. Replacement Plug the water hoses after disconnecting them. 1. Remove the EGR control valve in the sequence shown below. (1 ) EGR hoses (2) Vacuum hose (3) EGR function sensor connector (4) EGR control valve and gasket 2. Install a new gasket, and then install the EGR control valve in the reverse order of removal. Gartner Banana

FUEL EVAPORATIVE SYSTEM FUEL EVAPORATIVE SYSTEM DESCRIPTION The fuel evaporative system consists of the fuel vapor valve, the two-way check valve, the charcoal can- ister, the purge solenoid valve, the powertrain control module (engine), and the input devices. The amount of evaporative fumes introduced into the engine and burned is controlled by the solenoid valve in relation to the engine's operating conditions. To maintain the best engine performance, the solenoid valve is controlled by the powertrab control module (engine). THROTTLE 1-1 POSITION SENSOR I1 I I (IDLE SWITCH) 7 BAROMETIC ABSOLUTE PRESSURE SENSOR PARWNEUTRAL SWITCH (AT) MASS AIRFLOW SENSOR CRANKSHAFT POSITION SENSOR (SGT-SIGNAL) n - DUTY - LOW HIGH (ENGINE) CHARCOAL PURGE SOLENOID VALVE CANISTER HEATED OXYGEN SENSOR ENGINE COOLANT POWERTRAIN TEMPERATURE SENSOR CONTROL MODULE CHECK VALVE # 11 FUEL VAPOR VALVE Operation The purge solenoid valve is controlled by duty signals from the powertrain control module (engine) to per- form purging of the charcoal canister. Purging is done when these conditions are met: i/ 1. After warm-up. 2. Driving in gear. 3. Accelerator pedal depressed (idle switch OFF). 4. Heated oxygen sensor functioning normally. Gartner Banana

AIC CUT-OFF CONTROL SYSTEM AIC CUT-OFF CONTROL SYSTEM DESCRIPTION An NC cut-off system is used to improve idle smoothness after just starting the engine and to improve - acceleration performance. IGNITION SWITCH POWERTRAIN CONTROL MODULE (ENGINE) CRANKSHAFT POSITION - I DETERMINA- TION OF NC CUT-OFF & $1 . 1 THROTTLE I POSITION SENSOR AIC RELAY IGNITION SWITCH SENSOR 7 After engine has been started - The AJC is cut-off for 2 sec. just after the engine is started. Acceleration The AIC is cut-off upon wide-open-throttle acceleration for approx. 5 sec. Gartner Banana

F A/C CUT-OFF CONTROL SYSTEM D B AIC RE LAY SYSTEM INSPECTION 1. Turn the ignition switch ON. 2. Turn the blower switch and air conditioning sensor ON. 3. Start the engine. d 4. Verify that the A/C stops for approx. 2 sec. after the en- gine start. 5. Rotate the throttle link to fully open position. 6. Verify that the A/C stops for approx. 5 sec. after the throttle link to fully open position. 7. If not specified, inspect as following. PCME 1Q terminal voltage A/C relay Throttle position sensor AIC RELAY Inspection 1. Remove the A/C relay. 2. Check the continuity between the terminals of the relay. 3. If not specified, replace the A/C relay. B+: Battery positive voltage Terminal A - B Apply B+ B+ not applied Terminal C - D Yes No Gartner Banana

DECHOKE CONTROL SYSTEM DECHOKE CONTROL SYSTEM DESCRIPTION To clean out excess fuel in cylinders, as in the case of engine flooding, when the engine is cold, no fuel will be injected when the accelerator is held fully depressed while cranking the engine. CRANKSHAFT POSITION SENSOR (NE-SIGNAL) n POWERTRAIN CONTROL MODULE ENGINE COOLANT TEMPERATURE SENSOR I (ENGINE) 1 DETERMINA- TION OF FUEL CUT SPEED Gartner Banana

COOLANT FAN CONTROL F COOLANT FAN The coolant fan rotates at a constant velocity. 'L / Operation Condition TEN TERMINAL (DATA LINK CONNECTOR) IDLE SWITCH -----' OFF EXCEPT AT STARTING 'I ENGINE COOLANT TEMPERATURE ABOVE 97C0 (206.6F0) 1 COOLANT FAN - - ENGINE COOLANT TEMPERATURE SENSOR FAILED I A/C OPERATING CONDENSER FAN The condenser fan is operated by PCME. r The condenser fan rotates at a constant velocity. Operation Condition Except during acceralation Except at starting Other than wide open throttle Air conditioner is operating The condenser fan operates when above-mentioned conditions are satisfied. Engine coolant temperature is above 108°C (226.4OFj. TEN terminal grounded and idle switch off. Gartner Banana

CONTROL SYSTEM CONTROL SYSTEM PREPARATION 49 9200 162 Engine Signal Monitor Self-Diagnosis Checker 49 GO1 8 904 Sheet For inspection of powertrain control module (engine) For inspection of heated oxygen sensor For inspection of powertrain control module (engine) 49 GO18 903 For inspection of Adapter powertrain harness control module 49 B019 9AO For inspection of System heated oxygen Selector sensor Gartner Banana