1994 MAZDA MX-5 display

ON-BOARD DIAGNOSIS SYSTEM SELECT SW A Af ter-repair Procedure 1. Cancel the memory of malfunctions by disconnecting the negative battery cable at least 20 seconds and de- press the brake pedal. Reconnect the negative battery cable. 2. Connect the SST to the data link connector as shown. 3. Turn the ignition switch ON, but do not start the engine for six seconds. 4. Start and warm up the engine, then run it at 2,000 rpm for three minutes. 5. Verify that no code numbers are displayed. Gartner Banana

CONTROL SYSTEM Check Point for Each Terminal B+: Battery positive voltage Terminal -. - Connection to Abnormal voltage Possible cause Battery Always OV (Battery OK) Always OV Main relay a ROOM 10A fuse burned Open circuit in wiring from ROOM 1 OA fuse to PCME terminal 1A Main relay malfunction (Refer to page F-156) Open circuit in wiring from main relay to PCME termi- nal 1 B Ignition switch (Start position) a Main relay malfunction (Refer to page F-156) Open circuit in wiring from main relay to data link connector terminal +B Open or short circuit in wiring from data link connec- tor terminal MEN to PCME terminal 1 D Always OV (Starter turns) Always OV Open circuit in wiring from starter interlock switch to PCME terminal 1 C Self-Diagnosis Checker (Monitor lamp) Always B+ a Poor connection at PCME connector PCME malfunction I Always approx. 5V I a PCME malfunction Malfunction indicator light (MIL) Always below 2.5V (MIL always ON) Always below 2.5V Open circuit in wiring from combination meter to (MIL never ON) I PCME terminal I E a Short circuit in wiring from combination meter to PCME terminal 1 E PCME malfunction Always B+ Poor connection at PCME connector a PCME malfunction Self-Diagnosis Checker (Code No.) Always below 2.5V (No display on Self-Diagnosis Checker) Main relay malfunction (Refer to page F-156) a Open circuit in wiring from main relay to data link connector terminal +B Always B+ Always below 2.5V ("88" is displayed and buzzer sounds continuously) a Poor connection at PCME connector a PCME malfunction - Open or short circuit in wiring from data link connec- tor terminal FEN to PCME terminal I E Igniter Always OV a Refer to Code No.01 troubleshooting I (Refer to section GI Powertrain control module (transmission) Always B+ I PCME malfunction A/C relay malfunction (Refer to section U) a Open circuit in wiring from main relay to NC relay a Open circuit in wiring from NC relay to PCME termi- nal 1 J a Short circuit in wiring from NC relay to PCME termi- nal 1 J a PCME malfunction Always below 2.5V (NC does not operate) Always below 2.5V (Air conditioning sensor OFF but A/C operates) AIC relay Air conditioning sensor malfunction (Refer to section U) Poor connection at PCME connector PCME malfunction Always B+ Open circuit in wiring from PCME terminal 1 K to ground PCME malfunction Ground (MT) Always B+ Open (AT) Always OV Short circuit in wiring from PCME terminal 1 K to grounc PCME malfunction Coolant fan relay Always below 1 .OV (Coolant fan OK) Open or short circuit in wiring from fan relay to PCME terminal I L PCME malfunction Gartner Banana

ON-BOARD DIAGNOSIS SYSTEM K ON-BOARD DIAGNOSIS SYSTEM DESCRIPTION The self-diagnosis system integrated in the powertrain control module (Transmission) diagnoses mal- functions of the main sensors (input) and solenoid valves (output) and the powertrain control module (Transmission) itself. Malfunctions or intermittent malfunctions are memorized in the powertrain control module (Transmis- sion) to later be output as diagnostic trouble codes. The Self-Diagnosis Checker can be used to retrieve these diagnostic trouble codes. The Self-Diagno- sis Checker indicates a malfunction by displaying a code and sounding a buzzer. When the TAT and GND terminals of the data link connector are shorted with the ignition switch ON, the powertrain control module (Transmission) outputs any memorized diagnostic trouble codes by flashing the hold indicator light. PREPARATION SST 49 801 9 9AO For 49 H018 9A1 For diagnosis of diagnosis of System EC-AT Self-Diagnosis EC-AT selector checker Assembly of SST DIAGNOSTIC TROUBLE CODE Inspection Procedure Self-Diagnosis Checker 1. Connect the SST (System Selector) to the data link con- nector. 2. Set the SYSTEM SELECT switch A to position 2. 3. Set the TEST SW to SELF TEST position. 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

K ON-BOARD DIAGNOSIS SYSTEM - -- )IAGNOSTIC TROUBLE CODE N0.12 THROTTLE POSITION SENSOR ACTION I STEP INSPECTION Are there any poor connections at throttle position sensor and powertrain control module (transmission) connector or termi- nal? Yes Repair or replace connector I Go to next step Go to step 5 Connect a circuit tester to terminal as shown Is input voltage of throttle position sensor (TVO) at powertrain control module (transmission) OK? page K-45 1 (+) term. I (-) term. I Voltage (v)/ Condition 1 Yes No lgnition Go to next step ' 2T Ground valve Approx. closed I 0.8--4.3 position to wide open 1 throttle Go to next step Connect a circuit tester to terminals as shown Is input voltage of throttle position sensor (VREF) at powertrain control module (transmission) OK? page K-44 (+) term. (-) term. Voltage (V) Condition Approx. lgnition 4.55 ;p" 2A Ground Ignition 0 switch OFF Yes Check voltage at terminal 21 of powertrain control module (En- gine) Voltage: 4.5--5.5V (Ignition switch ON) If OK, go to next step If not OK, repair wiring andlor connector Check wiring and connectors form Powertrain control module (transmission) to throttle position sensor If OK, go to next step If not OK, repair wiring andlor connector Is throttle position sensor OK? Section F Yes No Yes Adjust or replace throttle position sensor t@? section F I Replace powertrain control module (transmission) t@? page K-45 is connect the negative battery cable for at least 20 seconds and depress the brake pedal Connect the battery cable and recheck for diagnostic trouble code Is diagnostic trouble code displayed? Daae K-21 Intermittent poor connection Check for cause Gartner Banana

ON-BOARD DIAGNOSIS SYSTEM K :TIC TROUBLE CODE No.55 VEHICLE SPEED PULSE GENERATOR ACTION Repair or replace connector INSPECTION control module (transmission) connector or terminal? I (+) term. 1 (-) term. I Voltage (v)( Condition I Are there any poor connections at vehicle speed pulse generator and powertrain No ' Go to next step Connect a circuit tester to terminal as shown Is input voltage of vehicle speed pulse generator at powertrain control module (transmission) OK? page K45 Engine Yes Engine I o ( stopped ( Yes Disconnect 20-pin powertrain control module (transmission) connector Is resistance between terminal 2J and ter- minal 2L OK? Go to step 5 I No I Go to next step Yes Go to step 5 Resistance: 200--400a Disconnect vehicle speed pulse genera- tor connector Is resistance between terminal E and ter- minal F OK? page K41 Resistance: 200--400n Disconnect the negative battery cable for at least 20 seconds and depress the brake mdal Sonnect the battery cable and recheck for jiagnostic trouble code Is diagnostic trouble code displayed? page K-21 45UOKX-019 Yes No Yes No Check wiring and connectors form powertrain control module (transmission) vehicle speed pules generator If OK, go to next step If not OK, repair wiring and/or connector Replace pulse generator Replace powertrain control module (transmission) us page K-45 Intermittent poor connection Check for cause Gartner Banana

K ON-BOARD DIAGNOSIS SYSTEM 1 KGNOSTIC TROUBLE CODE ~0.60 1-2 SHIFT SOLENOID VALVE INSPECTION Are there any poor connections at sole- noid valve and powertrain control module (transmission) connectors? shown Is output voltage of 1-2 shift solenoid valve at powertrain control module (trans- mission) OK? page K45 Bt: Battery positive voltage I (+) term. I (-) term. 1 voltage (v)I Condltlon 1 r B+ 1st gear 2E Ground o 2nd, 4GR Yes Disconnect 20-pin powertrain control module (transmission) connector Is resistance between terminal 2E and ground Resistance: 13-27Q Disconnect solenoid connector Is resistance between ground and termi- nal A of 1-2 shift solenoid valve OK? page K-42 Resistance: 13-278 Disconnect the negative battery cable for Yes at least 20 seconds and depress the brake pedal Connect the battery cable and recheck for code No Is diagnostic trouble code displayed? page K-21 ACTION Repair or replace connector GO to next step Check wiring and go to step 5 Go to next step Go to step 5 Go to next step Check wiring and connectors form powertrain control module (transmission) to 1-2 shift solenoid valve If OK, go to next step If not OK, repair wiring andlor connector Replace 1-2 shift solenoid valve Replace powertrain control module (transmission) page K-45 Intermittent poor connection Check for cause Gartner Banana