steering MAZDA MX-5 1994 User Guide

OIL PAN D RIGHT . . LEFT Removal Note Engine mount nut 1. Loosen the oil pan mounting bolts. 2. Remove the engine mounting nuts. 3. Lift the engine slightly with a hoist. Crossmember installation bolt and nut 1. Support the crossmember with a transmission jack. 2. Remove the crossmember installation bolts and nuts. 3. Separate the steering intermediate shaft from the pinion shaft. 4. Lower the crossmember until the clearance between the oil pan and the steering gear housing exceeds approx. 100mm (3.94 in). Oil pan 1. Remove the oil pan mounting bolts. Caution Pry tools can easily scratch the cylinder block and the oil pan contact surfaces. Prying off the oild pan can also easily bend the oil pan flange. Refer to the following instructions before remov- ing the oil pan. 2. Insert a screwdriver only at the points shown in the fig- ure. 3. Remove the oil pan. Oil baffle 1. Insert a screwdriver between the cylinder block and the oil baffle to separate them. 2. Remove the oil baffle. Installation Note Oil baffle 1. Remove all foreign material from the contact surfaces. 2. Apply a continuous bead of silicone sealant to the oil baffle along the inside of the bolt holes, and install within five minutes. Gartner Banana

Before beginning any service procedure. refer to section T of this manual for air bag system service warnings and audio antitheft system alarm conditions . FUEL AND EMISSION CONTROL SYSTEMS INDEX ............................ F- 2 ......................... OUTLINE F- 5 .............. SYSTEM DIAGRAM F- 5 VACUUM HOSE ROUTING DIAGRAM ...................... F- 6 WIRING DIAGRAM ............... F- 7 SPECIFICATIONS ............... F- 8 COMPONENT DESCRIPTIONS ... F- 9 ....... TROUBLESHOOTING GUIDE F- 11 ENGINE CONTROL OPERATION CHART ........................ F- 11 RELATIONSHIP CHART .......... F- 12 USING THIS SECTION ........... F- 13 DIAGNOSTIC INDEX ............. F- 15 SYMPTOM TROUBLESHOOTING . F- 17 PREPARATION ................... F- 75 ............. BASIC INSPECTION F- 75 .................. ADJUSTMENT F- 76 ON-BOARD DIAGNOSIS SYSTEM . . F- 78 DESCRIPTION .................. F- 78 PREPARATION .................. F- 79 DIAGNOSTIC TROUBLE CODE NUMBER ...................... F- 79 ... SWITCH MONITOR FUNCTION F- 95 INTAKE AIR SYSTEM .............. F- 98 COMPONENTS .................. F- 98 SYSTEM OPERATION ............ F-100 THROTTLE BODY ............... F-101 INTAKE MANIFOLD .............. F-102 ACCELERATOR PEDAL AND CABLE ........................ F-103 IDLE SPEED CONTROL SYSTEM ... F-104 DESCRI PTlON .................. F-104 PREPARATION .................. F-105 BAC VALVE ..................... F-105 IDLE AIR CONTROL VALVE ....... F-106 FUEL SYSTEM .................... F-107 DESCRIPTION .................. F-107 PREPARATION .................. F-108 SYSTEM OPERATION ............ F-109 FUEL TANK ..................... F-111 FUEL FILTER .................... F-113 FUEL PUMP .................... F-114 FUEL PUMP RELAY .............. F-117 PRESSURE REGULATOR ........ F-118 FUEL INJECTOR ................ F-119 PRESSURE REGULATOR CONTROL SYSTEM ......................... F-122 PRC SOLENOID VALVE .......... F-123 EXHAUST GAS RECIRCULATION (EGR) ........................... F-124 PREPARATION .................. F-124 .................. DESCRIPTION F-124 SYSTEM OPERATION F-125 ............ EGR SOLENOID VALVE (VACUUM) F-125 EGR SOLENOID VALVE (VENT) ... F-126 ......... EGR FUNCTION SENSOR F-126 ........... EGR CONTROL VALVE F-127 ................ EXHAUST SYSTEM F-128 .................. COMPONENTS F-128 OUTLINE OF EMISSION CONTROL ......................... SYSTEM F-129 ............. STRUCTURAL VIEW F-129 POSITIVE CRANKCASE VENTILATION ................... (PCV) SYSTEM F-130 ' DESCRIPTION .................. F-I ..................... PCV VALVE F-1 ..... FUEL EVAPORATIVE SYSTEM F- .................. DESCRIPTION F- ....... PURGE SOLENOID VALVE F- ........ TWO-WAY CHECK VALVE F- ...... THREE-WAY CHECK VALVE F- ............. FUEL VAPOR VALVE F- .......... CHARCOAL CANISTER F- CATALYTIC CONVERTER SYSTEM . F- .................. DESCRIPTION F- .......... THREE-WAY CATALYST F- AIC CUT-OFF CONTROL SYSTEM . . F- .................. DESCRIPTION F- ........... SYSTEM INSPECTION F- ...................... A/c RELAY F-1 36 ..... DECHOKE CONTROL SYSTEM F-137 .................. DESCRIPTION F-137 ......... COOLANT FAN CONTROL F-138 ....................... OUTLINE F-138 .................. COOLANT FAN F-139 ............... CONDENSER FAN F-139 ........... SYSTEM INSPECTION F-140 ........... COOLANT FAN RELAY F-140 ........ CONDENSER FAN RELAY F-140 ............... CONTROL SYSTEM F-141 .................. PREPARATION F-141 ............. STRUCTURAL VIEW F-142 POWERTRAIN CONTROL MODULE .............. (ENGINE) (PCME) F-143 ........ MASS AIRFLOW SENSOR F-152 CRANKSHAFT POSITION SENSOR F-153 ENGINE COOLANT TEMPERATURE ...................... SENSOR F-154 THROTTLE POSITION SENSOR . . F-154 HEATED OXYGEN SENSOR ...... F-156 MAIN RELAY .................... F-157 ............... CLUTCH SWITCH F-157 NEUTRAL SWITCH .............. F-157 STEERING PRESSURE SENSOR . F-158 45UOFX-001 Gartner Banana

INDEX 10. Charcoal canister lnspection . . . . . . . . . . . . . . . . . . page F-133 11. Powertrain control module (engine) Removal / Installation . . . . . . . . page F-143 lnspection . . . . . . . . . . . . . . . . . . page F-143 12. Crankshaft position sensor Removal . . . . . . . . . . . . . . . . . . . page F-153 lnspection . . . . . . . . . . . . . . . . . . page F-153 lnstallation . . . . . . . . . . . . . . . . . page F-153 13. Mass airflow sensor System inspection . . . . . . . . . . . page F-152 lnspection . . . . . . . . . . . . . . . . . . page F-152 14. Engine coolant temperature sensor Removal . . . . . . . . . . . . . . . . . . . page F-154 lnspection . . . . . . . . . . . . . . . . . . page F-154 Installation . . . . . . . . . . . . . . . . . page F-154 15. Throttle position sensor lnspection . . . . . . . . . . . . . . . . . . page F-154 Adjustment . . . . . . . . . . . . . . . . . page F-155 Replacement . . . . . . . . . . . . . . . page F-156 16. Heated oxygen sensor lnspection . . . . . . . . . . . . . . . . . . page F-156 Replacement . . . . . . . . . . . . . . . page F-156 17. Main relay lnspection . . . . . . . . . . . . . . . . . . page F-157 18. Clutch switch (MT) lnspection . . . . . . . . . . . . . . . . . . page F-157 Replacement . . . . . . . . . . . . . . . page F-157 19. Neutral switch (MT) lnspection . . . . . . . . . . . . . . . . . . page F-157 Replacement . . . . . . . . . . . . . . . page F-158 20. Steering pressure sensor lnspection . . . . . . . . . . . . . . . . . . page F-158 Replacement . . . . . . . . . . . . . . . page F-158 21. Fuel pump relay lnspection . . . . . . . . . . . . . . . . . . page F-117 Replacement . . . . . . . . . . . . . . . page F-117 22. PRC solenoid valve lnspection (On-vehicle) . . . . . . page F-123 lnspection . . . . . . . . . . . . . . . . . . page F-123 23. EGR solenoid valve (Vacuum) lnspection . . . . . . . . . . . . . . . . . . page F-125 24. EGR solenoid valve (Vent) lnspection . . . . . . . . . . . . . . . . . . page F-126 25. EGR function sensor lnspection . . . . . . . . . . . . . . . . . . page F-126 26. EGR control valve lnspection . . . . . . . . . . . . . . . . . . page F-127 Replacement . . . . . . . . . . . . . . . page F-127 27. NC relay lnspection . . . . . . . . . . . . . . . . . . page F-136 28. Coolant fan relay lnspection . . . . . . . . . . . . . . . . . . page F-140 29. Condenser fan relay lnspection . . . . . . . . . . . . . . . . . . page F-140 Gartner Banana

PURGE SOLENOID VALVE 7* AlC RELAY COOLANT FAN RELAY CONDENSER FAN RELAY STARTER STEERING PRESSURE SENSOR AIR CONDITIONING SENSOR ... CHECK VALVE FUEL-FILTER (HIGH-PRESSURE SIDE) / CRANKSHAFT POSITION SENSOR HEATED OXYGEN SENSOR ltT=I THREE-WAY CATALYST - REAR WINDOW DEFROSTER SWITCH COMBINATION SrmCH BLOWER SWlTCH STOPLIGHT SWITCH (MT) CLUTCH SWITCH (MT) - NEUTRALSWrrCH (MT) TEN TERMINAL PARWEUTRAL SWITCH (AT) VEHICLE SPEED SENSOR ENGINE COOLAMTEMPERATURE SENSOR EGR SOLENOID VALVE WEM) EGR SOLENOID VALVE (VACUUM) - w TO PCME Gartner Banana

Neutral swltch (MT) 7 PCV valve Powertrain control mod- ule (engine) (PCME) Purge solenoid valve Resonance chamber Steering pressure sen- Stoplight swltch I Throttle posltion sensor r [Two-way check valve Function jetects amount of intake air; sends signal to powertrain :ontrol module (engine) Li~ht illuminates when input device malfunctions - Light flashes to indicate trouble code number of input and output devices Detects in-gear condition; sends signal to powertrain :ontrol module (engine) - Controls blow by aas amount introduced into engine Detects the followlng: 1. A/C operation 2. Airlfuel ratio (Oxygen concentration) 3. Barometric absolute pressure 4. Braking signal 5. Cranking signal 6. EIL operation 7. Engine coolant temperature 8. Engine speed 9. In-gear condition 10. lntake air amount 11, lntake air temperature 12. No.1 piston TDC 13. PIS operation 14. Initial set signal 15. Throttle valve opening angle Controls operatlon of the followlng: 1. AIC (Cut off) 2. Fail-safe function 3. Fuel injection system 4. ldle speed control 5. Ignition timing control system 6. Monitor function 7. Purge control system 8. Lockup control svstem Controls vacuum to pressure regulator -- Adjusts fuel pressure supplied to fuel injectors Controls evaporative fumes from canister to intake man- ifold -- lm~roves mid-ranae torque characteristics -. Detects PIS operation; sends signal to powertrain con- trol module (engine) -- Detects braking operation (deceleration); sends signal to powertrain control module (engine) Reduces HC, CO, and NOx by chemical reaction Controls pressurein fuel tank Controls intake air quantity Detects position of the throttle valve closed throttle posi- tion; sends signal to powertrain control module (engine) Detects the throttle valve opening at a preset angle; sends si~nal to powertrain control module (engine) controls pressure in fuel tank Remark lntake air temperature sensor and fuel pump switch included Use Vref (5 volt) as power source ' Data link connector terminal TEN ' Data link connector terminal TEN Switch ON when in neutral 1, Air conditioning sesnor 2. Heated oxygen sensor 3. Barometric absolute pressure sensor 4. Stoplight switch 5. Ignition switch (START position) 6. Coolant fan relay Light and turn relay Blower switch 7. Engine coolant temperature sensor 8. Crankshaft position sensor (SGT-signal) 9. Neutral and dutch switches (MT) Parklneutral switch (AT) 10. Mass airflow sensor 11, lntake air temperature sensor 12. Crankshaft position sensor (SGC-signal) 13. Steering pressure switch 14. Data link connector 15. Throttle position sensor 1. NC relay 2. Self-diagnosis checker and MIL 3. Fuel injector 4. IAC valve 5. Igniter 6. Monitor lamp (Self-diagnosis checker) 7. Purge solenoid valve 8. Powertrain control module (transmission) (AT) D Controlled by duty signal from powertrain control module (engine) D PIS: ON when steering wheel turned Monolith type D Integrated throttle position sensor, Idle air control valve, and dashpol Gartner Banana

TROUBLESHOOTING GUIDE RELATIONSHIP CHART Fuel injector TEN Terminal (Data link connector) Ignition Switch (Start Position) Steering Pressure Sensor X X X X X X X X X X X X X X X xoo Blower Switch Headlight Switch Stoplight Switch Neutral and Clutch Switches (MT) Parklneutral switch (AT) Air Conditioning Sensor Idle Switch Throttle I BDL) Position Sensor I Sensor (NO) Barometric Absolute Pres- sure Sensor IGF Signal Heated Oxygen Sensor Engine Coolant Temperature Sensor Sensor Mass Air- flow Sensor Intake Air Temperature Sensor Crankshaft SGTSignal Position Sensor SGC-Signal Gartner Banana

CONTROL SYSTEM STRUCTURAL VIEW i 1. Powertrain control module (engine) 6. Heated oxygen sensor Inspection . . . . . . . . . . . . . . . . . . page F-144 Inspection . . . . . . . . . . . . . . . . . . page F-156 Removal / Installation . . . . . . . . page F-143 Replacement . . . . . . . . . . . . . . . page F-156 2. Crankshaft position sensor 7. Main relay Removal . . . . . . . . . . . . . . . . . . . page F-153 Inspection . . . . . . . . . . . . . . . . . . page F-156 lnspection . . . . . . . . . . . . . . . . . . page F-153 8. Clutch switch Installation . . . . . . . . . . . . . . . . . page F-153 Inspection . . . . . . . . . . . . . . . . . . page F-157 3. Mass airflow sensor Replacement . . . . . . . . . . . . . . . page F-157 System inspection . . . . . . . . . . . page F-152 9. Neutral switch Inspection . . . . . . . . . . . . . . . . . . page F-152 Inspection . , . . . . . . . . . . . . . . . . page F-157 4. Engine coolant temperature sensor Replacement . . . . . . . . . . . . . . . page F-157 Removal . . . . . . . . . . . . . . . . . . . page F-154 10. Steering pressure sensor Inspection . . . . . . . . . . . . . . . . . . page F-154 Inspection . . . . . . . . . . . . . . . . . . page F-158 Installation . . . , . . . . . . . . . . . . . page F-154 Replacement . . . . . . . . . . . . . . . page F-158 5. Throttle position sensor -,' Inspection . . . . . . . . . . . . . . . . . . page F-155 Adjustment . . . . . . . . . . . . . . . . . page F-155 Replacement . . . . . . . . . . . . . . . page F-156 Gartner Banana

CONTROL SYSTEM F Terminal voltage B+: Battery positive voltage Test condition I Voltage I Remark - - - - - - - - - - - - - - - - - - Connection to Battery Constant Ignition switch OFF Main relay - B+ OV lgnition switch (Start position) For backup - Ignition switch ON While cranking Lamp illuminated for 3 sec. after 1 4.5-5.5V ianition switch OFF+ON 1 B+ Approx. 1 OV Ignition switch ON - - OV Data link connector (MEN terminal) Test switch at "SELF-TEST" .. Lamp not illuminated after 3 sec. Test switch at "02 MONITOR" at idle Monitor lam illuminated & 4.5-5.5v . . I Malfunction indicator IighVData link connector (FEN ter- minal) With Self-Diagnosis Checker and System Selector Test switch at "02 MONITOR" at idle Monitor lamp not illuminated Light illuminated and buzzer sounded for 3 sec. after ignition switch OFF-ON B+ tor tesiswitch at "SELF-TEST" With Self-Diagnosis checker and system selector Below 2.5V 1 Light illuminated and buzzer sounded 1 Below 2.5V I With System Selec- Light not illuminated and buzzer not sounded after 3 sec. I Light not illuminated and buzzer 1 n. 1 B+ not sound I D+ 1 - #I, 4 lgniter (in IG COIL) #2,3 Igniter (in IG COIL) Powertrain control module (transmis- sion) - Ignition switch ON Idle Ignition switch ON Idle lgnition switch ON (Engine coolant temp, below 60°C {I 40°F)) Ignition switch ON AtC relay Air conditioning sensor ON at idle Air conditioning sensor OFF at idle Ground (MT) - OV Approx. 0.2V OV Approx. 0.2V Below 1 .OV B+ Below 2.5V B+ - - - - , * Open (AT) - Ignition switch ON ( Below 1 .O V I Engine coolant temp. I Below .OV I ldle Above 97°C (206.6OF1 Ignition switch ON I I B+ Ignition switch ON Coolant fan relay B+ . - Other conditions lgnition switch On dround data link connector TEN terminal I Blow 1.0" I B+ Vehicle speed sensor ldle switch OFF While driving Vehicle sto~wed ldle switch (in throttle position sensor) 2-5V 1 or 7V . , Accelerator pedal released Accelerator ~edal de~ressed - Stoplight switch OV B+ Brake pedal released Brake ~edal deoressed lgnition switch ON Steering pressure sensor OV B+ I I - Ignition switch ON B+ - PIS ON (at idle) PIS OFF (at idle) Air conditioning sensor Air conditioning sensor ON (Igni- tion switch ON) Air conditioning sensor OFF (Igni- tion switch ON) OV B+ - Below 2.5V B+ Blower motor ON Gartner Banana

CONTROL SYSTEM B+: Battery positive voltage Terminal 1 M 7 1 N 10 1 P 1 Q 1 R 1 S 1 T 1 U Connection to Abnormal voltage Always approx. 1 V Always approx. 7V Possible cause r Vehicle speed sensor malfunction r Short circuit in wiring from vehicle speed sensor to PCME terminal 1 M Vehicle speed sensor - r Vehicle speed senso~malfunction r Open circuit in wiring from vehicle speed sensor to PCME terminal 1 M r Throttle position sensor misadjustment (Refer to page F-154) r Short circuit in wiring from PCME terminal 1 N to throttle position sensor 6 PCME malfunction Always OV Throttle position sensor (idle terminal) Always B+ r Throttle position sensor misadjustment (Refer to page F-154) r Open circuit in wiring from PCME terminal 1 N to throttle position sensor r Open circuit in wiring from throttle position sensor to ground Stoplight switch Always OV (Stoplights OK) r Open circuit in wiring from stoplight switch to PCME terminal 10 r Steering pressure sensor malfunction (Refer to page F-158) Short circuit in wiring from PCME terminal 1 P to steering pressure sensor r PCME malfunction r Steering pressure sensor malfunction (Refer to F-158) r Open circuit in wiring from PCME terminal 1 P to steering pressure sensor Open circuit in wiring from steering pressure sensor to ground r Air conditioning sensor malfunction (Refer to section U) r Short circuit in wiring from PCME terminal 1 Q to air conditioning sensor r Poor connection at PCME connector r PCME malfunction Always OV Steering pressure sensor Always B+ -- Air conditioning sensor Always OV (with blower switch ON) Air conditioning sensor malfunction (Refer to section U) Open circuit in wiring from PCME terminal 1Q to air conditioning sensor Open circuit in wiring from air conditioning sensor to blower switch Always B+ (with blower switch ON) (Blower fan OK) EGR solenoid valve (vent) Always OV r Refer to Code No.29 Troubleshooting (Refer to page F-92) Short circuit in wiring from blower switch to PCME terminal 1 S r Poor connection at PCME connector PCME malfunction Always OV (Blower fan OK) Blower switch Always B+ (Blower fan OK) Open circuit in wiring from blower switch to PCME terminal IS EGR solenoid (vacu- um) Always OV r Refer to Code No.28 Troubleshooting (Refer to paae F-92) Headlight switch Always OV (Headlights OK) r Open or short circuit in wiring from headlight relay to PCME terminal 1 U Gartner Banana

CONTROL SYSTEM Replacement Replace the neutral switch as shown in the figure. STEERING PRESSURE SENSOR Inspection 1. Disconnect the steering pressure sensor connector. 2. Connect an ohmmeter to the switch. 3. Start the engine and let it idle. Check continuity of the switch while turning the steering wheel. PIS 1 Continuity Turnina Yes " I t ~ot turning I NO 4. If not as specified, replace the steering pressure sensor. Replacement Replace the steering pressure sensor as shown in the figure. Gartner Banana