1994 MAZDA MX-5 wiring

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

F CONTROL SYSTEM B+: Battery positive voltage Abnormal voltage Possible cause Terminal 1 v Connection to Neutral switch malfunction (Refer to page F-157) Clutch switch malfunction (Refer to page F-156) Short circuit in wiring from PCME terminal 1 V to neutral or clutch switch Neutral switch malfunction (Refer to page F-157) 0 Clutch switch malfunction (Refer to page F-156) 0 Open circuit in wiring from PCME terminal 1 V to neutral or clutch switch Poor connection at PCME connector 0 ParWneutral switch malfunction (Refer to section K) 0 Short circuit in wiring from parWneutral switch to PCME terminal 1V 0 ParWneutral switch malfunction (Refer to section K) 0 Open circuit in wiring from parWneutral switch to PCME terminal 1 V Always OV Neutral switchlClutch switch (MT) Always B+ Always OV ParWneutral switch (AT) Always B+ Poor contact at ground terminal 0 Open circuit in wiring from PCME to ground Sround More than OV Crankshaft position sensor (SGT-signal) Always OV or approx. 5V Always below 2V or 4V Refer to Code No.03 troubleshooting (Refer to page F-84) Refer to code No.08 Troubleshooting (Refer to page F-86) 0 Short circuit in wiring from PCME terminal 2H to data link connector terminal TEN Mass airflow sensor Always OV Data link connector (Terminal TEN) 0 Open circuit in wiring from PCME terminal 2H data link connector terminal TEN 0 Open circuit in wiring from data link connector terminal GND to around Always B+ Igniter EGR function sensor Always OV Always approx. OV or approx. 5v Refer to Code No.01 troubleshooting (Refer to paae F-83) 0 Refer to Code No.16 Troubleshooting (Refer to page F-89) 0 Short circuit in wiring from PCME terminal 2K tothrottle position sensor, PCME, or mass airflow sensor Poor connection at PCME connector PCME malfunction Vre f Always OV lllumination light ON when rear window defroster switch ON Open or short circuit in wiring from rear window de- froster switch to PCME terminal 2L Always below 1 .ov Rear window defroster switch Open circuit in wiring from ignition switch to rear win- dow defroster switch Rear window defroster switch malfunction (Refer to section T) lllumination light never ON Open circuit in wiring from PCME terminal 2M to throttle position sensor 0 Open circuit in wiring from PCME terminal 2K to throttle position sensor 0 Open circuit in wiring from PCME terminal 20 to throttle position sensor Always constant Throttle position sensor Alwavs above 1V 0 Throttle position sensor misadjustment Refer to Code No.15 troubleshooting (Refer to page F-88) OV after warm-up Heated oxygen sensor Always approx, 1V after warm-up 0 Refer to Code No.17 troubleshooting (Refer to page F-90) Refer to Code No.08 troubleshooting (Refer to page F-86) Mass airflow sensor Always OV or approx. 5V Gartner Banana

CONTROL SYSTEM B+: Battery positive voltage Terminal Connection to Abnormal voltaae Possible cause Mass airflow sensor (Intake air temperature sensor) Refer to Code No.10 troubleshooting (Refer to page F-87) Always OV or approx. 5V Intake air temperature sensor malfunction (Refer to page F-152) Refer to Code No.09 troubleshooting (Refer to page F-87) Engine coolant temper- ature sensor Always OV or approx. 5V r Engine coolant temperature sensor malfunction (Refer to page F-154) Refer to Code No.25 Troubleshooting (Refer to page F-91) Always OV or B+ PRC solenoid valve r Open or short circuit in wiring from condenser fan relay to PCME terminal 25 PCME malfunction Open or short circuit in wiring from fuel pump relay to PCME terminal 2T Condenser fan relay Always below 2.OV Fuel pump relay Always below 1 .OV Main relay malfunction (Refer to page F-156) r Open or short circuit in wiring from fuel injector to PCME terminal 2U or 2V Always OV Fuel injector ldle air control valve Purge solenoid valve Always B+ Always OV or B+ Always OV or B+ PCME malfunction r Refer to Code No.34 troubleshooting (Refer to page F-93) ldle air control solenoid valve malfunction (Refer to page F-I 06) r Refer to Code No.26 troubleshooting (Refer to page F-91) r Purge solenoid valve malfunction (Refer to pane F-132) -- Fuel injector Always OV Main relay malfunction (Refer to page F-156) Open or short circuit in wiring from fuel injector to PCME terminal 2Y or 22 Always B+ PCME malfunction Gartner Banana

G CHARGING SYSTEM WEAR LIMIT LINE Inspection Rotor 1. Winding damage (1) Check the resistance between the slip rings with an J ohmmeter. Specification: 3.5--4.5SU20°C (68°F) (2) If it is not within specification, replace the rotor. 2. Ground of field coil (1) Check for continuity between each slip ring and the core with an ohmmeter. (2) Replace the rotor if there is continuity. 3. Slip ring surface If the slip ring surface is rough, use fine sandpaper to repair it. Stator 1. Wiring damage (1) Check for continuity between the stator coil leads with an ohmmeter. (2) Replace the stator if there is no continuity. 2. Ground of stator coil (1)~heck for no continuity between the stator coil leads and the core with an ohmmeter. (2) Replace the stator if there is continuity. Brush If the brushes are worn almost to or beyond the limit, replace them. Standard: 21.5mm (0.846 in) Minimum: 8.0mm (0.31 in) Gartner Banana

G STARTING SYSTEM Check 1 Check 3 Check 2 STARTER Caution Obtain the code number and deactivate the audio anti-theft system before disconnecting the bat- tery. (Refer to section T.) Removal / Installation 1. Disconnect the negative battery cable. 2. Disconnect the wiring from the starter. 3. Remove the starter bracket. (MT only) 4. Raise the front of the vehicle and support it with safety stands. 5. Remove the bolts and the starter. 6. Install in the reverse order of removal. Tightening torque Nut O: 10-11 N.m (100-120 kgfam, 87-100 in4bf) Bolt, Nut O: 38-51 N.m (3.8-53 kgf-m, 28-38 ft4bf) Bolt 0: 16-22 N.m (1.6-2.3 kgf.m, 12-16 ft-lbf) Bolt 0: 38-51 N.m (3.8-5.3 kgf-m, 28-38 ft-lbf) Gartner Banana

STARTING SYSTEM Yoke assembly 1. Wiring damage of field coil (1) Check for continuity between the connector and the brushes with an ohmmeter. (2) Replace the yoke assembly if there is no continuity. 2. Ground of field coil (1) Check for no continuity between the connector and the yoke with an ohmmeter. (2) Repair or replace the yoke assembly if there is conti- . nuity. 3. Installation of field coil Replace the yoke assembly if the field coil is loose. Magnetic Switch 1. Wiring damage (S terminal - M terminal) Check for continuity between S terminal and M terminal with an ohmmeter. Replace the magnetic switch if there is no continuity. 2. Wiring damage (S terminal - body) Check for continuity between S terminal and the body with an ohmmeter. Replace the magnetic switch if there is no continuity. Brush and Brush Holder Insulation of brush holder Check for no continuity between each insulated brush and the plate with an ohmmeter. Replace the brush holder if there is continuity. Gartner Banana

K ON-BOARD DIAGNOSIS SYSTEM Ill I 4. Connect the SST (Self-Diagnosis Checker) to the SST (System Selector) and a ground. 5. Set the SELECT SW to position A. 6. Turn on the ignition switch. ii 7. Verify that "88" flashes on the digital display and that the buzzer sounds for 3 seconds. 8. If "88" does not flash, check the main relay and 2s and 2Q terminals of the powertrain control module (transmis- sion) for an open or short circuit. 9. If "88" flashes and the buzzer sounds continuously for more than 20 seconds, check the wiring to terminal 1C of the powertrain control module (Transmission) for an open or short circuit. If necessary, replace the powertrain control module (Transmission) and repeat from step 2. 10. Note any code(s) and check for the cause(s). Repair as necessary. (Refer to page K-12.) 11. After repairs are made, do the After-Repair Procedure (page K-21) to verify that there are no remaining codes. Troubleshooting If a diagnostic trouble code is shown on the SST (Self-Diagnosis Checker), check for the cause by using the ch&t related to the code shown. Diagnostic trouble code ~U)DE NO. 1 LOCATION OF MALFUNCTION I BUZZER (HOLD INDICATOR LIGHT FLASH CYCLE) Throttle position sensor or circuit 06 Vehicle speed sensor or circuit 55 ON OFF Vehicle speed pulse generator or circuit 60 - 61 1-2 shift solenoid valve or circuit 62 - -- - 3-2 control solenoid valve or circuit 64 T 2-3 shift solenoid valve or circuit 63 - 3-4 shift solenoid valve or circuit -----a Lockup control solenoid valve or circuit -- --i---- - - - audrur - -, -. - 0.4 sec. - --I-& cl.2sec + 2 1.6sec * - 4 sec - - Gartner Banana

ON-BOARD DIAGNOSIS SYSTEM K )IAGNOSTIC TROUBLE CODE N0.06 VEHICLE SPEED SENSOR INSPECTION STEP ACTION Repair or replace connector Are there any poor connections at vehicle speed sensor and powertrain control module (Transmission) connectors? Yes Go to next step Connect a circuit tester to terminal as shown. Is input voltage of vehicle speed sensor at powertrain control module (Transmission) OK? page K-44 Yes Go to step 5 1 (+) term. I (-) term. ( Voltage (v)( Condition I Go to next step Below 1.5 While Remove instrument cluster Is there continuity between terminal 2D of meter connector and terminal 1 M of pow- ertrain control module (Transmission) Yes Go to next step Repair or replace wiring and/or connector Connect circuit tester to terminals 2D and 2A of meter connector Does pointer of circuit tester move slightly when front wheels are slowly turned? Yes Go to next step Replace vehicle speed sensor section T Disconnect the negative battery cable for at least 20 seconds and depress the brake pedal Connect the battery cable and recheck for code. Is diagnostic trouble code displayed Dane K-21 Yes Replace powertrain control module (transmission) page K-45 Intermittent poor connection check for cause Gartner Banana