relay MAZDA MX-5 1994 User Guide

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 F TROUBLESHOOTING GUIDE ENGINE CONTROL OPERATION CHART Output Devices and Engine Conditions ENGINE CONDITION CRANK- WARMING MEDIUM LOAD ING UP (DUR- ACCEL- HEAVY (COLD ERATION LOAD OUTPUT ENGINE) INGIDLE) COLD WARM DEVICE u I I I FUEL INJEC- FUELIN- nON Rich Normal JECToR AMOUNT Rich FUEL PUMP RELAY I IG: ON DECEL (ENGINE ERATION NOT RUNNING] No Injec- Fuel cut I Normal I tion IGNITER Depends on engine condition I PURGE SOLENOID VALVE OFF ON (Purge) OFF I I IDLE AIR ON ON ON CONTROL (Fixed (Closed ON (Fixed duty) (Closed OFF BAC VALVE duty) loop duty) loop duty) VALVE AIR VALVE OPEN CLOSED - AIC RELAY I OFF PRC SOLENOID VALVE OFF (Vacuum to pressure regulator) I I EGR SO- VENT ON LENOID OFF (System operates: amount of OFF JALVE VACUUM EGR changes) Gartner Banana

TROUBLESHOOTING GUIDE Warning Fuel vapor is hazardous. It can very easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel in the fuel system is under high pressure when the engine is not running. 4 Warning Fuel line spills and leaks are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete the following "Fuel Line Safety Procedures". 35UOFX-008 F-73 F-73 F-74 Fuel Line Safety Procedures A. Release the fuel pressure before disconnecting a fuel line. 1. Start the engine. u 2. Disconnect the fuel pump relay connector. 3. After the engine stalls, turn the ignition switch to OFF. 4. Reconnect the fuel pump relay connector. B. Avoid leakage. 1. When disconnecting a fuel line hose, wrap a rag around it to protect against fuel leakage. 2. Plug the hose after removal. C. Install hose clamps to secure the fuel pressure gauge connections. Self-Diagnosis Checker does not indicate Diagnostic Trouble Code No. but MIL comes on Self-Diagnosis Checker indicates Diagnostic Trouble Code No, of input device but MIL never comes ON Blower fan operates but no cool air is discharged 32 33 34 Pinching Hose When pinching an air hose or fuel hose with pliers, wrap the hose with a rag to prevent damage. MIL always ON MIL never ON NC does not work Checking ignition spark When checking ignition spark condition, hold the high- tension lead with insulated pliers. Note If a timing light is used to check for spark, some lights do not light at the number 2 and 4 cylinders even if the ignition system is normal. J Gartner Banana

TROUBLESHOOTING GUIDE SYMPTOM TROUBLESHOOTING 2 CRANKS NORMALLY BUT WILL NOT START (NO COMBUSTION) Engine cranks at normal speed but shows no sign of "firing" ESCwPTION : Battery in normal condition Throttle valve not held wide open throttle while cranking Fuel in tank rROUBLESHOOTlNG HINTS] ecause of no combustion, possibly no fuel is injected to engine or no ignition at all cylinders 1 No spark O Low fuel line pressure lanition control malfunction @ Low engine compression ignition system component malfunction I No fuel injection Fuel pump does not operate Fuel injector does not operate INSPECTION ACTION :heck if strong blue spark is visible at disconnected iigh-tension lead while cranking engine :heck if "00" is displayed on Self Diagnosis Checker ~ith ignition switch ON page F-79 Sonnect data link connector terminals F/P and GND ~ith jumper wire and check for fuel pump operating sound with ignition switch ON page F-114 Yes - No - Yes No - Yes - No Go to Step 3 Go to Step 2 Check ignition system (Refer to Troubleshooting "Misfire") mf Section G Diagnostic Trouble Code No. displayed Check for cause (Refer to specified check sequence) page F-81 "88" flashes Check PCME terminal 1 E voltage ojg. page F-145 Specification: Battery positive voltage (Ignition switch ON) 0 If OK, replace PCME us? page F-143 Q If not OK, check wiring between PCME and Self-Diagno- sis Checker page F-7 Check if engine starts in this condition 0 If starts, check fuel pump relay f@ page F-117 r3 If does not start, go to Step 5 Go to Step 4 Gartner Banana

F TROUBLESHOOTING GUIDE INSPECTION Check if battery positive voltage exists at fuel pump connector fuel pump positive terminal with jumper wire connected.(~tep 3 Check for fuel injector operating sound while crank- ing engine Check if battery positive voltage exists at fuel injector connector B terminal wire with ignition switch ON Connect data link connector terminals F/P and GND with jumper wire and check for correct fuel line pres- sure with ignition switch ON page F-110 Fuel Line pressure: 265--314 kPa f2.7-3.2 kgf/crn2, 38-46 psi) Check for correct engine compression Section B Engine compression: 1,255--883 kPa {12.&9.0 kgf/crn2, 182-1 28 psi)-300 rpm Check if spark plugs are OK WEAR AND CARBON BUILDUP BURNS PLUG GAP 1.0-l.lmm DAMAGE AND (0.040-0.043 in) DETERIORATION DAMAGE Try known good PCME and check if condition im- proves page F-144 - Yes - No Yes Yes - No Yes Yes - No - Yes ACTION Check continuity of fuel pump page F-114 Check fuel pump relay page F-117 Go to Step 7 Go to Step 6 Check PCME terminals 2A, 2U, 2V, 2Y and 22 voltages @3F page F-147 Check for open circuit in wiring between main relay and fuel injector page F-7 Go to next step Low pressure Check fuel line pressure while pinching fuel return hose 0 If fuel line pressure quickly increases, check pressure regulator page F-118 0 If fuel line pressure gradually increases, check for clog- ging between fuel pump and pressure regulator If not clogged, check fuel pump maximum pressure page F-115 Go to next step Check engine condition @3F Section B w Worn piston, piston rings or cylinder wall Defective cylinder head gasket w Distorted cylinder head Improper valve seating w Valve sticking in guide Go to next step Repair, clean, or replace Section G Gartner Banana

TROUBLESHOOTING GUIDE INSPECTION ACTION Check if PCME terminal voltages are OK (1 R, 1 T, ZD, 20 and 20) us page F-146 Yes Go to next step Check for cause (Refer to "Check Point for Each Termi- nal") Djp paae F-148 Check if strong blue spark is visible at each discon. nected high-tension lead while cranking engine Yes - No Go to next step Check ignition system (Refer to Troubleshooting "Misfire") Section G Check for EGR system malfunction page F-124 Yes - No Repair or replace Go to next step Check for fuel injector operating sound at each in- Yes Go to Step 10 jector at idle No - Yes Go to Step 9 Check if battery positive voltage exists at fuel injec- tor connector B terminal with ignition switch ON Check if fuel injector resistance is OK page F-119 Resistance: 12-1 6R G If OK, check wiring between injector and PCME page F-7 o If not OK, replace injector L@? page F-119 No - Yes Check wiring between main relay and fuel injector page F-7 Go to next step Check for correct engine compression Section B Engine compression: 1,255-883 kPa I12.8-9.0 kgflcm2, 182-1 28 psi)-300 rpm Check engine condition Section B I Worn piston, piston rings or cylinder wall r Defective cylinder head gasket r Distorted cylinder head r Improper valve seating Valve sticking in guide No - Yes :heck if spark plugs PLUG GAP 1 .O-1 .l mm (0.04+0.043 in} DETERIORATION 30 to next step qepair, clean, or replace Section G Try known good PCME and check if condition im- roves @r page F-144 Gartner Banana

F TROUBLESHOOTING GUIDE DESCRIPTION I Blower fan operates but cool air not expelled ITROUBLESHOOTING HINTS] Open or short circuit in wiring harness NC relay malfunction 34 Air conditioning sensor malfunction Magnetic clutch malfunction PCME malfunction AIC DOES NOT WORK INSPECTION ;round terminal B at NC relay with jumper wire Yes tnd check if condenser fan operates when ignition ;witch is turned ON #C RELAY I ;round terminal B at PCME 1 J terminal with jump- Yes ,r wire and check if condenser fan operates when gnition switch is turned ON - No :heck if Air conditioning sensor is OK Yes Section U ACTION 30 to next step 30 to A/C system Troubleshooting Section U 30 to next step qepair wire between PCME and A/C relay page F-7 Try known good PCME page F-144 ;heck Air conditioning sensor and wiring Section U 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

F ON-BOARD DIAGNOSIS SYSTEM CODE No. I 03 (SGT SIGNAL) iTEP I INSPECTION ACTION - Yes - No ' I Are there any poor connections in crankshaft posi- tion sensor circuit? Repair or replace connector I Go to next step I 1 Is Code No.04 present at same time? Yes - No Go to next ste~ I GO to Step 5 I Yes - No 3 Go to next step I Is there continuity between crankshaft position sen- sor terminal A and ground? Check for open circuit in wiring from crankshaft position sensor to ground Go to next step Check for open circuit in wiring from crankshaft position sensor to main relay 1 Is there battery positive voltage at crankshaft posi- tion sensor terminal B Yes - No Yes 5 6 Go to next step Is there continuity between crankshaft position sen- sor and PCME? Crankshaft position sensor I PCME C I 2 E Is there approx. 5V at PCME terminal 2E? (With crankshaft position sensor connector discon- nected) Check for open circuit in wiring from crankshaft position sensor to PCME Yes Go to next step I Replace PCME as page 6143 Replace crankshaft position sensor page F-153 Yes - No - 7 Check for short circuit in wiring from crankshaft position sensor to PCME 15UOFX-026 Is there approx. 5V at crankshaft position sensor terminal C? (At harness-side connector with con- nector disconnected) I CODE No. I 04 (SGC SIGNAL) I STEP I INSPECTION 1'1 Are there any poor connections in crankshaft posi- tion sensor circuit? Repair or replace connector Go to next step Go to next step 121 Is Code No.03 also present? Go to Step 5 Go to next step Is there continuity between crankshaft position sen- sor terminal A and ground? Check for open circuit in wiring from crankshaft position sensor to ground Go to next step Check for open circuit in wiring from crankshaft position sensor to main relay 4 Is there continuity between crankshaft position sen- sor and PCME? Go to next step Is there battery positive voltage at crankshaft posi- tion sensor terminal B? Yes - No No - Yes - No 6 Check for open circuit in wiring from crankshaft position sensor to PCME Go to next step Replace PCME page F-143 Crankshaft position sensor I PCME D Replace crankshaft position sensor page F-153 Check for short circuit in wiring from crankshaft position sensor to PCME 2G 7 Is there approx. 5V at PCME terminal 2G? (With crankshaft position sensor connector discon- nected) Is there approx. 5V at crankshaft position sensor terminal D? (At harness-side connector with con- nector disconnected) Yes No Gartner Banana

ON-BOARD DIAGNOSIS SYSTEM F Circuit Diagram TO IGNITION SWITCH TO BATTERY MAIN RELAY :AF*, CRANKSHAFT POSITION SENSOR Gartner Banana