1994 MAZDA MX-5 display

TROUBLESHOOTING GUIDE TROUBLESHOOTING HINTS] D Factors other than engine malfunction Clutch slipping Brake dragging Low tire pressure Unrecommended tire size 25 O AirIFuel mixture too lean or too rich Fuel line pressure low or high Insufficient fuel injection @ Poor ignition 6 Low engine compression POOR ACCELERATION Overloaded D Low intake air amount Throttle valve not open fully Clogged intake air system )ESCRIPTION I Performance poor while accelerating INSPECTION :heck factors other than engine Clutch slipping Section H D Brake dragging Section P t Low tire pressure Section Q D Unrecommended tire size Section Q :heck if throttle valve wide open throttles when jepressing accelerator fully Check if "00" is displayed on Self-Diagnosis Check- er with ignition switch ON page F-79 Check switches for correct operation with Self- Diagnosis Checker Monitor Lamp and ignition switch ON page F-95 SELECT SW A SYSTEM SELECT 1 - Yes - No Yes - No - Yes - No Yes - No ACTION Go to next step Repair Go to next step Check if accelerator cable is correctly installed * page 0 If OK, check throttle body ce Page 0 If not OK, install accelerator cable correctly page Go to next step -- Diagnostic Trouble Code No. displayed Check for cause (Refer to specified check sequenc US page "88" flashes Check PCME terminal 1 E voltage Us Page Specification: Battery positive voltage (Ignition switch ON) 0 If OK, replace PCME * Page 9 If not OK, check wiring between PCME and Self- sis Checker * Page Go to next step Lamp not ONlOFF with specified switch Check for cause (Refer to specified check sequenc * Paw Lamp always ON Check wiring between PCME terminal 1 D and Self nosis Checker * Page ! F-103 ! F-101 I F-103 :e) r F-81 ! F-145 I F-143 Diagno- ! F-7 :e) ! F-96 -Diag- ! F-7 Gartner Banana

TROUBLESHOOTING GUIDE I IESCRIPTION I Engine runs rough while decelerating and abnormal combustion occurs in exhaust system 26 TROUBLESHOOTING HINTS] 3 AirIFuel mixture too rich Air cleaner element clogged Fuel injection control malfunction (Fuel cut control) Fuel injector fuel leakage 0 Ignition timing misadjustment iTEP I INSPECTION RUNS ROUGH ON DECELERATIONIAFTERBURN ;heck if "00" is displayed on Self-Diagnosis Check- ?r with ignition switch ON page F-79 Sheck switches for correct operation with Self- Diagnosis Checker Monitor Lamp and ignition switch ON page F-95 SELECT SW A SYSTEM SELECT 1 Check for correct ignition timing at idle @= page F-76 lgnition timing: 10" 2 lo BTDC Check if fuel cut operation is OK during decelera- tion Fuel cut: Above 1,900 rpm after warm-up Yes Yes Yes - No Yes 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 03% page F-145 Specification: Battery positive voltage (Ignition switch ON) 0 If OK, replace PCME IGS page F-143 0 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 G+F page F-7 Go to next step Adjust page F-76 Go to next step Try known good PCME I@= page F-144 Gartner Banana

TROUBLESHOOTING GUIDE TEP 27 INSPECTION KNOCKING ACTION 30 to next step TROUBLESHOOTING HINTS] > AirIFuel mixture too lean @I Incorrect ignition timing (too advance) Fuel injection amount incorrect Q Overheating Fuel line pressure decreases while accelerating @I Carbon deposits in engine :heck if "00" is displayed on Self-Diagnosis Check- br with ignition switch ON page F-79 Yes Diagnostic Trouble Code No. displayed Check for cause (Refer to specified check sequence) page F-81 "88" flashes Check PCME terminal 1 E voltage uzf page F-145 Specification: Battery positive voltage (Ignition switch ON) 0 If OK, replace PCME page 6143 s If not OK, check wiring between PCME and Self-Diagno- sis Checker page F-7 >heck switches for correct operation with Self- liagnosis Checker Monitor Lamp and ignition ;witch ON as page F-95 SELECT SW A Yes - No Go to next step Lamp not ONIOFF with specified switch Check for cause (Refer to specified check sequence) page F-96 MONl LAMP II- SYSTEM SELECT 1 Lamp always ON Check wiring between PCME terminal 1 D and Self-Diag- nosis Checker uzf page F-7 Zheck if PCME terminal voltages are OK :1R, IT, 2D, 20, and 2Q) page F-146 Yes Go to next step Check for cause (Refer to "Check Point for Each Termi- nal") uzf page F-148 Sheck for correct intake manifold vacuum at idle Yes - No Go to next step Vacuum: More than 450 mmHg (17.7 InHg) VACUUM GAUGE Check for air leakage of intake air system components as page F-100 Check if air cleaner element is clean page F-76 Yes - No Go to next step Replace air cleaner element page F-99 Gartner Banana

TROUBLESHOOTING GUIDE rROUBLESHOOTlNG HINTS] > Poor connection or damaged fuel system or fuel evaporative system 3 Charcoal canister overflow due to fuel evaporative system malfunction 28 INSPECTION Check if fuel leak or damage are visible at fuel sys- tem and fuel evaporative system FUEL ODOR ACTION IESCRIPTION I Gasoline odor in cabin Yes Repair or replace page F-107 30 to next step Check if "00" is displayed on Self-Diagnosis Check- er with ignition switch ON page F-79 SELECT SW A SYSTEM SELECT 1 I Yes - No - Yes So 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) o If OK, replace PCME page F-143 o If not OK, check wiring between PCME and Self-Diagno- sis Checker page F-7 Check if vacuum is felt at purge solenoid valve with engine running and throttle valve opened (Neutral switch connector disconnected) Go to Step 5 Check for purge solenoid valve operating sound in this condition o If OK, check vacuum hoses for clogging page F-6 o If not OK, go to next step Apply battery positive voltage and ground to purge solenoid valve and check if air flows through valve Yes Check PCME terminal 2X voltage page F-146 Replace purge solenoid valve @S page F-132 Try known good PCME Daae F-144 Gartner Banana

TROUBLESHOOTING GUIDE F POOR FUEL ECONOMY I [TROUBLESHOOTING HINTS] Nhile fuel consumption is drastically increased during city driving, short-run operation, stop and go driving, extended winterwarm- ~p periods, etc., as opposed to "trip" mileage, an attempt should be made to determine these factors when confronted with "poor mileage" conditions. However, since the operator is not always at fault, the following is offered. 3 Operator depressing accelerator more than usual due to O Alcohol blended fuel used low engine power @ High vehicle load Poor ignition Low tire pressure Low intake air amount Unrecommended tire used Electric spark advance control malfunction Brake dragging Clutch slipping @ Fuel cut control malfunction Exhaust component restricted @ High idle speed AirIFuel mixture too rich High fuel line pressure INSPECTION Check factors other than engine Low tire pressure Section Q Unrecommended tire used @zT Section Q Clutch slipping Section H Brake dragging Section P Exhaust component restricted @zT page F-128 ACTION - Yes Go to next step Repair Check if air hoses are connected correctly @zT page F-99 Yes - No Go to next step Repair @zT page F-99 Check if air cleaner element is clean page F-76 Yes - No Go to next step Replace page 699 Check if "00" is displayed on Self-Diagnosis Check- er with ignition switch ON @zT page F-79 Yes Go to next step SELECT SW A SYSTEM SELECT 1 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) 6 If OK, replace PCME page F-143 6 If not OK, check wiring between PCME and Self-Diagno- sis Checker page F-7 Check switches for correct operation with Self- Diagnosis Checker Monitor Lamp and ignition switch ON page F-95 SELECT SW A Yes Go to next step ~~p Lamp not ONIOFF with specified switch Check for cause (Refer to specified check sequence) @zT page F-96 Lamp always ON Check wiring between PCME terminal 1 F and Self-Diag- nosis Checker us page F-7 Gartner Banana

ON-BOARD DIAGNOSIS SYSTEM ON-BOARD DIAGNOSIS SYSTEM DESCRIPTION When troubles occur in the main input devices or output devices, check for the cause using the SST. Q Failures of each input and output device are indicated and retrieved from the powertrain control module (engine) as diagnosis trouble code numbers. Note For input devices, the PCME continuously checks for malfunctions. For output devices, it checks for malfunctions only in a three-second period after the ignition switch is turned to ON, or the TEN termi- nal of the data link connector is grounded. - INPUT SIGNALS POWERTRAIN CONTROL MODULE (ENGINE) I- -t INPUT DEVICES FAIL-SAFE FUNCTION . ON-BOARD ,, DIAGNOSIS -+ SYSTEM - - 1 I I MALFUNCTIQN DISPLAY FUNCTION -t b P v C-- MONITOR FUNCTION u SYSTEM SELF-DIAGNOSIS SELECTOR CHECKER I CHECK Gartner Banana

ON-BOARD DIAGNOSIS SYSTEM PREPARATION SST 1 SELECT SW A STEM SELECT 1 * SYSTEM SEUC . TEST SW - SYSTEM SELECT i # SELF TEST DIAGNOSTIC TROUBLE CODE NUMBER Inspection procedure 1. Connect the SSTs to the data link connector and a ground. 2. Set the select switch to position A. 49 B019 9AO System Selector 3. Set the System Selector to position 1 and SELF TEST as shown. For diagnosis 4. Turn the ignition switch ON. 5. Verify that 88 flashes on the digital display and that the buzzer sounds for 3 sec. after turning the ignition switch ON. 6. If 88 does not flash, check the main relay (Refer to page F-156.), power supply circuit, and check connector wir- mg. 7. If 88 flashes and the buzzer continues for more than 20 sec., check for a short circuit between the powertrain control module (engine) terminal 1 E and the data link connector. Replace the powertrain control module (en- gine) if necessary and perform Steps 3 and 4 again. 8. Note any code numbers and check for the causes by re- ferring to the check sequences shown on pages F-83 to F-93. Repair as necessary. 9. After repairs, cancel the code numbers by performing the "After-repair procedure". (Refer to page F-94.) Gartner Banana

ON-BOARD DIAGNOSIS SYSTEM F Code Numbers Malfunction display On-board diagnosis system Code No. 0 1 03 Pattern of output signal (Self-Diagnosis System Checker) Sensor or subsystem IGF signal SGT signal Fail-safe ON OFF A-n-L ON OFF m No SGT signal ON OFF JuUu Cancels fuel injection No SGC signal Cancels fuel injection and electronic spark distribution SGC signal Basic fuel injection amount fixed as for two driving modes (1) ldle switch: ON (2) ldle switch: OFF ON OFF Mass airflow sensor Open or short circuit Engine coolant tempera- ture sensor ON OFF -JLnn Open or short circuit Intake air temperature sen- sor (Mass airflow sensor) Maintains constant 35°C {95"F} command Maintains constant 20°C {68"F} command Open or short circuit ON OFF -nNLnM- Maintains constant com- mand of throttle valve wide open throttle Throttle position sensor Open or short circuit ON OFF Barometric absolute pres- sure sensor Maintains constant command of sea level pressure Open or short circuit Heated oxygen sensor (Inactivation) EGR function sensor Sensor output continues less than 0.55V 180 sec. after engine exceeds 1,500 rpm Cancels engine closed loop operation ON OFF ON OFF --nMM.A ON OFF --rMMMA Open or short circuit Heated oxygen sensor (In- version) Maintains constant command of EGR valve ON OFF JlnMkm Sensor output continues unchanged 20 sec. after engine exceeds 1,500 rpm PRC solenoid valve Cancels engine closed loop operation Open or short circuit Open or short circuit I - ON OFF m Purge solenoid valve ON OFF EGR solenoid valve (vacu- um) ON OFF Open or short circuit EGR solenoid valve (vent) ldle air control valve - Open or short circuit ON OFF m Open or short circuit I - Gartner Banana