display MAZDA MX-5 1994 User Guide

TROUBLESHOOTING GUIDE lo 1 LOW IDLE SPEEDIROUGH IDLE - AFTER WARM-UP 3ESCRIPTION I Engine runs normally at idle during warm-up but vibrates excessively after warm-up ;TROUBLESHOOTING HINTS] I> Idle speed control malfunction b AirlFuel mixture too lean Air leakage of intake air system Low fuel line pressure INSPECTION Check if "00" is displayed on Self-Diagnosis Check- er with ignition switch ON m? page F-79 Check switches for correct operation with Self- Diagnosis Checker Monitor Lamp and ignition switch ON page F-95 SELECT SW A Disconnect idle air control valve connector at idle and check if engine condition is charged IAC VALVE - Yes No - Yes - No Yes O Air/Fuel mixture too rich Fuel injection control malfunction (Correction for coolant temperature) @ Poor ignition spark Q Low engine compression ACTION Go to next step Diagnostic Trouble Code No. displayed Check for cause (Refer to specified check sequence) page F-81 "88" flashes Check PCME terminal 1 E voltage page F-145 Specification: Battery positive voltage (Ignition switch ON) 6 If OK, replace PCME page F-143 Q If not OK, check wiring between PCME and Self-Diagno- sis Checker page F-7 Go to next step Lamp not ONIOFF with specified switch Check for cause (Refer to specified check sequence) page F-96 Lamp always ON Check wiring between PCME terminal 1 D and Self-Diag- nosis Checker page F-7 Go to next step Check idle air control valve page F-106 Gartner Banana

TROUBLESHOOTING GUIDE INSPECTION >heck if throttle valve is closed throttle position Yes when accelerator released I 11 :heck if "00" is displayed on Self-Diagnosis Check- Yes w with ignition switch ON @? page F-79 HIGH IDLE SPEED - AFTER WARM-UP SELECT SW A SYSTEM SELECT 1 FROUBLESHOOTING HINTS] Excessive intake air supplied to engine O Throttle valve not fully closed @ ldle speed control malfunction Air valve not closing ldle air control valve stuck Incorrect coolant temperature signal STEP 1 >heck switches for correct operation with Self- I Yes liagnosis Checker Monitor Lamp and ignition ;witch ON page F-95 SELECT SW A ACTION Go to next step Check if throttle linkage is correctly installed and operates freely @? page F-103 o If OK, go to next step o If not OK, clean, adjust or replace linkage Daae 6103 Go to next step - Diagnostic Trouble Code No. displayed Check for cause (Refer to specified check sequence) @? page F-81 "88" flashes Check PCME terminal 1 E voltage @S page F-145 Specification: Battery positive voltage (Ignition switch ON) 6 If OK, replace PCME E=T page F-143 o If not OK, check wiring between PCME and Self-Diagno- sis Checker @? page F-7 Go to next step Lamp not ONlOFF with specified switch Check for cause (Refer to specified check sequence) E=T page F-96 am^ always ON Check wiring between PCME terminal ID and Self-Diag- IOS~S Checker @? page F-7 Gartner Banana

TROUBLESHOOTING GUIDE ldle speed control malfunction Engine speed feedback control malfunction ldle air control valve stuck 12 INSPECTION LOW IDLE SPEED - WHEN AIC, PIS, OR EIL ON Check if "00" is displayed on Self-Diagnosis Check- er with ignition switch ON @? page F-79 SELECT SWA SYSTEM SELECT 1 I Check switches for correct operation with Self- Diagnosis Checker Monitor Lamp and ignition switch ON page F-95 SELECT SW A DESCRIPTIOH MONITOR [LAMP &\L SYSTEM SELECT 1 : Engine speed decreases at idle when NC, PIS, or EIL ON NC, PIS, headlights, blower fan and electric coolant fan operate normally Check if continuity exists between data link con- nector terminal TEN and ground --., rrROUBLESHOOTlNG HINTS] Disconnect idle air control valve connector at idle and check if engine condition is changed IAC VALYE CONNECTOR /' Yes - No Yes Yes No - Yes - No - ACTION Go to next step Diagnostic Trouble Code No. displayed Check for cause (Refer to specified check sequence) US= page F-81 "88" flashes Check PCME terminal 1 E voltage * page F-145 Specification: Battery positive voltage (Ignition switch ON) 6 If OK, replace PCME page F-143 G If not OK, check wiring between PCME and Self-Diagno- sis Checker page F-7 Go to next step Lamp not ONIOFF with specified switch Check for cause (Refer to specified check sequence) as page F-96 Lamp always ON Check wiring between PCME terminal I D and Self-Diag- nosis Checker @T page F-7 Check for short circuit in wiring between data link connec- tor terminal TEN and ground as page F-7 Go to next step Try known good PCME page F-144 Check idle air control valve @? page F-106 Gartner Banana

TROUBLESHOOTING GUIDE )ESCRIPTION I Engine starts normally but vibrates excessively just after starting TROUBLESHOOTING HINTS] D Fuel injection control and idle speed control malfunction Q Idle speed misadjustment Start signal not input to PCME O Ignition timing misadjustment a INSPECTION ACTION -- 13 Zheck if "00" is displayed on Self-Diagnosis Check- sr with ignition switch ON page F-79 ROUGH IDLE JUST AFTER STARTING Yes Go to next step Diagnostic Trouble Code No. displayed Check for cause (Refer to specified check sequence) page F-81 "88" flashes Check PCME terminal I E voltage page -45 Specification: Battery positive voltage (Ignition switch ON) + If OK, replace PCME page F-143 Q If not OK, check wiring between PCME and Self-Diagno- sis Checker page F-7 Zheck switches for correct operation with Self- Diagnosis Checker Monitor Lamp and ignition switch ON r@= page F-95 SELECT SW A Yes Go to next step MONITOR SYSTEM SELECT 1 Lamp not ONlOFF with specified switch Check for cause (Refer to specified check sequence) page F-96 Lamp always ON Check wiring between PCME terminal 1 D and Self-Diag- nosis Checker page F-7 :heck if PCME terminal 1 C voltage is OK page F-145 Yes Go to next step I Check for cause (Refer to "Check Point for Each Termi- nal") uzf page F-148 Voltage: Approx. 10V (While cranking) 3heck for correct ignition timing at idle @? page F-76 Yes Check for correct idle speed page F-77 I ldle speed: 850 +. 50 rpm (MT) 800 2 50 rpm (AT) gnition timing: 10" + lo BTDC Q If OK, go to next step Q If not OK, adjust idle speed page F-77 Adjust E+F page F-76-1 Try known good PCME and check if condition im- )roves page F-144 Gartner Banana

TROUBLESHOOTING GUIDE INSPECTION Check if "00" is displayed on Self-Diagnosis Check- er with ignition switch ON page F-79 14 - -- Check for correct idle speed page F-77 IDLE MOVES UP AND DOWN Idle speed: 850 2 50 rpm (MT) 800 + 50 rpm (AT) GND TEN I DESCRIPTION I Engine speeds up and down periodically at idle [TROUBLESHOOTING HINTS] O Fuel cut occurs at idle O Air leakage of intake air system Air valve not closing after warm-up and idle speed @ Poor ignition spark reaches to fuel cut speed 8 AirIFuel mixture too rich Q Fuel injection amount fluctuating Fuel evaporative system malfunction Bad contact point inside mass airflow sensor 8 Low engine compression 5'=€% CONNECT TERMINAL AIR ADJUSTING SCREW Check for correct ignition timing at idle * page F-76 Ignition timing: 10" 2 lo BTDC - Yes - No - Yes - No Yes ACTION Go to next step Diagnostic Trouble Code No. displayed Check for cause (Refer to specified check sequence) @r page F-81 "88" flashes Check PCME terminal 1 E voltage re page F-145 Specification: Battery positive voltage (Ignition switch ON) 3 If OK, replace PCME page 6143 3 If not OK, check wiring between PCME and Self-Diagno- sis Checker page F-7 So to next step 2heck if idle speed can be adjusted by turning air adjust ;crew 3 If OK, adjust idle speed 3 If not OK, check air valve page F-105 20 to next step idjust I@= page F-76 Gartner Banana

TROUBLESHOOTING GUIDE FROUBLESHOOTING HINTS] O Incorrect idle speed ldle speed misadjustment ldle speed control malfunction 15 Q AirIFuel mixture too rich or lean Injector clogged or inoperative Low fuel line pressure ENGINE STALLS AT IDLE - ALWAYS Low intake ai; amount or air leakage Q Poor ianition s~ark DESCRIPTION I Engine starts normally but vibrates excessively and stalls at idle in every condition INSPECTION ;heck for correct intake manifold vacuum at idle Vacuum: More than 450 mmHg f17.7 inHg) VACUUM GAUGE / :heck if air cleaner element is clean @S page F-76 ?heck if "00" is displayed on Self-Diagnosis Check- 3r with ignition switch ON page F-79 SELECT SW A MONITOR . SYSTEM SELECT 1 ;heck switches for correct operation with Self- liagnosis Checker Monitor Lamp and ignition ;witch ON page F-95 SELECT SWA SYSTEM SELECT 1 - Yes - No Yes - No Yes No - Yes - No Go to next step ACTION Check for air leakage of intake air system components * page F-1 00 Go to next step Replace air cleaner element K@- page F-99 Go to next step Diagnostic Trouble Code No. displayed Check for cause (Refer to specified check sequence) * page F-81 "88" flashes Check PCME terminal 1 E voltage @a page F-145 Specification: Battery positive voltage (Ignition switch ON) 6 If OK, replace PCME @a page F-143 .r, If not OK, check wiring between PCME and Self-Diagno- sis Checker * page F-7 Go to next step Lamp not ONlOFF with specified switch Check for cause (Refer to specified check sequence) * page F-96 Lamp always ON Check wiring between PCME terminal 1 D and Self-Diag- nosis Checker @f page F-7 Gartner Banana

TROUBLESHOOTING GUIDE 5 ENGINE STALLS AT IDLE - BEFORE WARM-UP IESCRIPTION I Engine starts normally but vibrates excessively and stalls at idle before warm-up TROUBLESHOOTING HINTS] D Low intake air amount Q) AirIFuel mixture too lean Idle speed control malfunction Air leakage of intake air system Air cleaner element clogged Q Poor atomization of fuel Low RVP (summer) fuel used in cold weather Check if "00" is displayed on Self-Diagnosis Check- ar with ignition switch ON page F-79 SELECT SW * SYSTEM SELECT 1 Check switches for correct operation with Self- Diagnosis Checker Monitor Lamp and ignition switch ON SELECT SW A t~= page F-95 -A SYSTEM SELECT 1 MONITOR :heck if PCME terminal voltages are OK :2D, 20 and 2Q) @T page F-146 :heck for correct intake manifold vacuum at idle Vacuum: More than 450 mmHg (17.7 inHg} VACUUM GAUGE - Yes - No Yes - No Yes - No Yes ACTION I Go to next step Diagnostic Trouble Code No. displayed Check for cause (Refer to specified check sequence) page F-81 "88" flashes Check PCME terminal 1 E voltage w page F-145 Specification: Battery positive voltage (ignition switch ON) Q If OK, replace PCME page F-143 4 If not OK, check wiring between PCME and Self-Diagno- sis Checker page F-7 Go to next step Lamp not ONlOFF with specified switch Check for cause (Refer to specified check sequence) w page F-96 Lamp always ON Check wiring between PCME terminal 1 D and Self-Diag- nosis Checker page F-7 Go to next step Check for cause (Refer to "Check Point for Each Termi- nal") t@ page F-148 Go to next step Check for air leakage of intake air system components page F-95 Gartner Banana

TROUBLESHOOTING GUIDE F 18 ENGINE STALLS DURING START-UP DESCRIPTKlN I Engine unexpectedly stops running while starting VROUBLESHOOTING HINTS] @ Misfire occurs when depressing accelerator Q Lack of engine torque for start-up AirIFuel mixture too rich or too lean AirIFuel mixture too rich or too lean Incorrect ignition timing Weak ignition INSPECTION Check if brakes are dragging Section P Check if "00 is displayed on Self-Diagnosis Check- er with ignition switch ON * page F-79 SELECT SW A Check switches for correct operation with Self- Diagnosis Checker Monitor Lamp and ignition switch ON @ page F-95 Disconnect heated oxygen sensor connector and :heck if condition improves SENSOR CONNECTOR -3 I I - Yes - No Yes Yes No - Yes Low intake air amount Low en~ine com~ression ACTION Repair us Section P Go to next step Go to next step -- Diagnostic Trouble Code No. displayed Check for cause (Refer to specified check sequence) page F-81 "88" flashes Check PCME terminal 1 E voltage us page F-145 Specification : Battery positive voltage (Ignition switch ON) If OK, replace PCME rc+r page F-143 6 If not OK, check wiring between PCME and Self-Diagno- sis Checker e page F-7 Go to next step Lamp not ONIOFF with specified switch Check for cause (Refer to specified check sequence) uw page F-96 Lamp always ON Check wiring between PCME terminal 1 D and Self-Diag- nosis Checker page F-7 Check heated oxygen sensor @s page F-156 Go to next step Gartner Banana

TROUBLESHOOTING GUIDE 3ESCRIPTION ( Engine unexpectedly stops running while decelerating or after deceleration JROUBLESHOOTING HINTS] Ingine speed drops too much when releasing accelerator D Idle speed control malfunction Q Engine feedback control malfunction D Fuel cut control malfunction @ Idle speed misadjustment 19 INSPECTION :heck if "00" is displayed on Self-Diagnosis Check- 3r with ignition switch ON page F-79 ENGINE STALLS ON DECELERATION >heck switches for correct operation with Self- Diagnosis Checker Monitor Lamp and ignition switch ON page F-95 SELECT SW A MONITOR kt \A SYSTEM SELECT 1 Disconnect heated oxygen sensor connector and :heck if condition improves >heck if PCME terminal voltages are OK [2D, 20,2U, 2V 2Q, 2Y and 22) its page F-146 - Yes - No Yes Yes No - Yes ACTION Go to next step Diagnostic Trouble Code No. displayed Check for cause (Refer to specified check sequence) page Fa1 "88" flashes Check PCME terminal 1 E voltage us? page F-145 Specification: Battery positive voltage (Ignition switch ON) 6 If OK, replace PCME page F-143 o If not OK, check wiring between PCME and Self-Diagno. sis Checker page F-7 Go to'next step Lamp not ONJOFF with specified switch Check for cause (Refer to specified check sequence) page F-96 Lamp always ON Check wiring between PCME terminal 1 D and Self-Diag- nosis Checker page F-7 Check heated oxygen sensor @Tage F-156 Go to next step Go to next step Check for cause (Refer to "Check Point for Each Termi- nal") E%= page F-148 Gartner Banana

TROUBLESHOOTING GUIDE DESCRIPTION I : Engine unexpectedly stops running at idle when AIC, PIS, or EIL ON AX, PIS, headlight, blower fan and electric coolant fan OK 20 [TROUBLESHOOTING HINTS] O ldle speed control malfunction No input signal from switch ldle speed misadjustment ldle air control valve stuck ENGINE STALLS AT IDLE - WHEN AIC, PIS, OR EIL ON INSPECTION Check if "00" is displayed on Self-Diagnosis Check- er with ignition switch ON * page F-79 SELECT SW A SYSTEM SELECT 1 Check switches for correct operation with Self- Diagnosis Checker Monitor Lamp and ignition switch ON tw page F-95 SELECT SW A Check if PCME terminal voltages are OK (IG, 1 P, 1 U, 2D,2Q and 2W) page F-146 Check for correct idle speed page F-77 ldle speed: 850 2 50 rpm (MT) 800 2 50 rpm (AT) GND TEN 1 AIR ADJUSTING SCREW CONNECT TERMINAL - Yes - No Yes - No Yes - No Yes - No Go to next step ACTION Diagnostic Trouble Code No. displayed Check for cause (Refer to specified check sequence) page F-81 "88" flashes Check PCME terminal 1 E voltage page F-145 Specification: Battery positive voltage (Ignition switch ON) 0 If OK, replace PCME page F-143 s If not OK, check wiring between PCME and Self-Diagno- sis Checker page F-7 Go to next step Lamp not ONlOFF with specified switch Check for cause (Refer to specified check sequence) page F-96 Lamp always ON Check wiring between PCME terminal 1 D and Self-Diag- nosis Checker IS page F-7 Go to next step Check for cause (Refer to "Check Point for Each Termi- nal") page F-148 Go to next step Adjust page F-77 Gartner Banana