check engine light MAZDA MX-5 1994 User Guide

F ON-BOARD DIAGNOSIS SYSTEM Procedure - Set conditions to deactivate each switch a All accessories OFF a Transmission in neutral a All pedals released Verify that monitor lamp does not illuminate Neutral and Clutch switches (MT) Parklneutral switch (AT) Depress clutch pedal Verify that monitor lamp does not illuminate Return transmission to neutral NO PC: a Neutral or clutch switch malfunction (Refer to F-146) a Open circuit in related wire harness a Powertrain control module (engine) terminal 1V malfunction (Refer to page F-146) - Shift transmission into gear Verify that monitor lamp illuminates with clutch pedal is re- leased PC: a Clutch switch malfunction (Refer to page F-157) 35UOFX-046 I ParWneutral switch OK Shift into P or N range Check each switch and related wire harness a Clutch and Neutral switch :Refer to page F-I57 a Idle switch (in throttle position sensor) :Refer to page F-154 a Stoplight switch :Refer to Section T Headlight switch :Refer to Section T 1 Check each switch as described I I NO - ldle switch (in throttle position sensor) a Blower switch :Refer to Section T a Air conditioning sensor :Refer to Section U a Rear window defroster switch :Refer to Section T a ParWneutral switch :Refer to Section K YES PC: a ParWneutral switch malfunction (Refer to Section K) a Open or short circuit in related wire harness a PCME terminal 1 V voltage incorrect (Refer to page F-I 46) PCME malfunction - Shift transmission into L, S, D, or P range Check that monitor lamp illuminates 35UOFX-06 NO + YES I 1 I ldle switch OK I L I PC: Throttle position sensor malfunction (Refer to page F-144) a Short circuit in wire harness from throttle position sensor to PCME a PCME terminal 1 N voltage incorrect (Refer to page F-145) a PCME malfunction - Depress accelerator pedal and check that monitor lamp illu- minates f NO --c YES PC: a Throttle position sensor malfunction (Refer to page F-144) Open circuit in wire harness from throttle position sensor to PCME PCME terminal 2M voltage incorrect (Refer to page F-146) Release acceleration pedal and check that monitor lamp does not illuminate 2 YES I I Gartner Banana

CONTROL SYSTEM F Terminal voltage B+: Battery positive voltage Test condition I Voltage I Remark - - - - - - - - - - - - - - - - - - Connection to Battery Constant Ignition switch OFF Main relay - B+ OV lgnition switch (Start position) For backup - Ignition switch ON While cranking Lamp illuminated for 3 sec. after 1 4.5-5.5V ianition switch OFF+ON 1 B+ Approx. 1 OV Ignition switch ON - - OV Data link connector (MEN terminal) Test switch at "SELF-TEST" .. Lamp not illuminated after 3 sec. Test switch at "02 MONITOR" at idle Monitor lam illuminated & 4.5-5.5v . . I Malfunction indicator IighVData link connector (FEN ter- minal) With Self-Diagnosis Checker and System Selector Test switch at "02 MONITOR" at idle Monitor lamp not illuminated Light illuminated and buzzer sounded for 3 sec. after ignition switch OFF-ON B+ tor tesiswitch at "SELF-TEST" With Self-Diagnosis checker and system selector Below 2.5V 1 Light illuminated and buzzer sounded 1 Below 2.5V I With System Selec- Light not illuminated and buzzer not sounded after 3 sec. I Light not illuminated and buzzer 1 n. 1 B+ not sound I D+ 1 - #I, 4 lgniter (in IG COIL) #2,3 Igniter (in IG COIL) Powertrain control module (transmis- sion) - Ignition switch ON Idle Ignition switch ON Idle lgnition switch ON (Engine coolant temp, below 60°C {I 40°F)) Ignition switch ON AtC relay Air conditioning sensor ON at idle Air conditioning sensor OFF at idle Ground (MT) - OV Approx. 0.2V OV Approx. 0.2V Below 1 .OV B+ Below 2.5V B+ - - - - , * Open (AT) - Ignition switch ON ( Below 1 .O V I Engine coolant temp. I Below .OV I ldle Above 97°C (206.6OF1 Ignition switch ON I I B+ Ignition switch ON Coolant fan relay B+ . - Other conditions lgnition switch On dround data link connector TEN terminal I Blow 1.0" I B+ Vehicle speed sensor ldle switch OFF While driving Vehicle sto~wed ldle switch (in throttle position sensor) 2-5V 1 or 7V . , Accelerator pedal released Accelerator ~edal de~ressed - Stoplight switch OV B+ Brake pedal released Brake ~edal deoressed lgnition switch ON Steering pressure sensor OV B+ I I - Ignition switch ON B+ - PIS ON (at idle) PIS OFF (at idle) Air conditioning sensor Air conditioning sensor ON (Igni- tion switch ON) Air conditioning sensor OFF (Igni- tion switch ON) OV B+ - Below 2.5V B+ Blower motor ON Gartner Banana

CHARGING SYSTEM G TROUBLESHOOTING Check 1 Check if battery p Check battery (Refer to page G-8) J Check 2 I. Turn ignition switch ON Check wire harness 2. Check if voltage exists at each terminal of alternator Check 3 YES 1. Start engine Check alternator (Refer to page G-10) 2. Check if alternator warning light goes off I YES Check if drive belt t Adjust or replace drive belt (Refer to page G-14) 1 YES I Check for dark current (Refer to page G-3) I Check 1 BATTERY r"; Check 3 I ALTERNATOR WARNING LIGHT Check 2 B+: Battery positive voltage I I I B 1 Approx. 12V 1 Approx. 12V I B+ ON ON (Idle) L S 45UOGX-006 OV Approx. 12V Approx. 1V Approx. 12V B+ B+ Gartner Banana

IGNITION SYSTEM G GND TEN I I I IGNITION TIMING 1. Check the condition of the engine (spark plugs, leaks in hoses, etc.). 2. Verify that all accessories are OFF. 3. Warm up the engine to the normal operating tempera- ture. Note When using an externally powered timing light and/or tachometer connect it to the power connector (Blue: l-pin). Warning Do not ground the power connector. terminal (Blue: l-pin); some fuses will be burned. 4. Connect a timing light and tachometer to the data link connector terminal (IG-). 5. Connect the SST and set TEST SW to "SELF TEST" or connect data link connector terminals TEN and GND with a jumper wire. 6. Check the idle speed, and set it to specification if neces- sary (Refer to section F.) ' Idle speed (rpm):800-900 (MT) 75-50 (AT) 7. Verify that the timing mark (white) on the crankshaft pulley is aligned with the indicator pin. Ignition timing: 9"-11" BTDC (at idle) 8. If the marks are not aligned, remove the ignition coil bracket and push the ignition coil aside for easy access and then loosen the crankshaft position sensor lock bolts, and turn the crankshaft position sensor to make the adjustment. 9. Tighten the crankshaft position sensor lock bolts to the specified torque. Tightening torque: 19-25 N-m (1 3-2.6 kgf~m, l4--19 ft.lbf) 10. After adjusting the ignition timing, disconnect the jumper wire or SST from the data link connector. 11. Increase the engine speed and verify that the ignition timing advances. Gartner Banana

G IGNITION SYSTEM BURNS PLUG GAP DAMAGE AND DETERIORATION DAMAGE SPARK PLUG Removal 1 Installation Caution Pulling on the wire part of the spark plug lead may i/ break it. To remove the lead, pull only on the boot. Caution To avoid breaking the spark plug be sure to fit the socket squarely over it. Tighten to the specified torque. Spark plug tightening torque: 15--22 N-m (1.5--2.3 kgf-m, 11-16 ft-lbf) Spark Test 1. Disconnect the high-tension lead from the spark plug. 2. Connect a new spark plug to the high-tension lead. 3. Hold with insulated pliers approx. 5-10mm (0.20-4.39 in) from a ground. 4. Crank the engine and verify that a strong blue spark is visible. . -.d' Note If a timing light is used to check for spark, some lights do not light at Nos.:! and 4 cylinders even if the igni- tion system is normal. Inspection Check the following and replace the spark plugs as neces- sary. 1. Damaged insulation. 2. Worn electrodes. 3. Carbon deposits. If cleaning is necessary, use a plug cleaner or a wire brush. Wipe upper insulator. 4. Damaged gasket. Plug gap: 1 .O-1 .l mm (0.040-0.043 in) Gartner Banana

K TROUBLESHOOTING TROUBLESHOOTING GENERAL NOTES A problem with the EC-AT may be caused by the engine, the EC-AT powertrain, the hydraulic control LJ system, or the electronic control system. When troubleshooting, therefore, begin from these points, which can be inspected quickly and easily. The recommended troubleshooting sequence is described below. WHEEL CHOCK 63 TEMPERATURE w-7u'C (1461WF) Step 1 : On-board Diagnosis System Inspection Check for diagnostic trouble code(s) memorized in the powertrain control module (Transmission) with the Self- Diagnosis Checker. (Refer to page K-11 .) Note You can also check the flashing sequence of the hold indicator light for diagnostic trouble code(s). (Refer to page K-1 1 .) Step 2: Mechanical System Test Check the engine stall speed, time lag, and line pres- sure. (Refer to page K-22.) Step 3: Road Test Check the shift point, shift schedule, and shift shock. (Refer to page K-29.) Gartner Banana

K ELECTRICAL SYSTEM COMPONENTS ELECTRICAL SYSTEM COMPONENTS PREPARATION SST 49 GO1 8 904 Sheet 49 9200 162 Monitor, Engine Signal - 49 DO1 9 902 Adapter Harness For inspection of powertrain control module (transmission) terminal voltage For inspection of powertrain control module (transmission) terminal voltage p@ HOLD For inspection of powertrain control module (transmission) terminal voltage HOLD SWITCH lnspection lnspection of operation 1. Turn the ignition switch from OFF to ON. 2. Verify that the hold indicator light is not illuminated. De- press the hold switch and verify that the hold indicator -J light illuminates. 3. If not as specified, check the terminal voltage of the hold switch. lnspection of voltage 1. Remove the front console. 2. Turn the ignition switch ON. 3. Measure voltage at the hold switch connector. B+: Battery positive voltage Position (V): Voltage Normal (V) Depressed (V) 4. If not as specified, check the continuity of the hold switch. Connector terminal A B+ 0 B 0 0 Gartner Banana

P BRAKE SYSTEM k FIRST PEDAL VACUUM GAUG DEPRESSION FORCE GAUGE POWER BRAKE UNIT Quick Inspection, On-vehicle Power brake unit function check (Simple method) ii Step 1 1. With the engine stopped, depress the pedal a few times. 2. With the pedal depressed, start the engine. 3. If immediately after the engine starts the pedal moves down slightly, the unit is operating. Step 2 1. Start the engine and let it run 1 or 2 minutes. 2. Stop the engine. 3. Depress the pedal with the usual force. 4. If the first pedal stroke is long and becomes shorter with subsequent strokes, the unit is operating. 5. If a problem is found, inspect for damage or improper connection of the check valve or vacuum hose. Repair if necessary, and inspect it once again. Step 3 1. Start the engine. 2. Depress the pedal with the usual force. 3. Stop the engine with the pedal depressed. 4. Hold the pedal down for about 30 seconds. 5. If the pedal height does not change, the unit is operating. ,, 6. If there is a problem, check for damage or improper con- nection of the check valve or vacuum hose. Repair if necessary, and check once again. If the nature of the problem is still not clear after following the 3 steps above, follow the more detailed check described in "Method using tester," below. (Method using tester) Connect the SST, vacuum gauge, and pedal depression force gauge as shown in the figure. After bleeding the air from the SST, conduct the test as described in the 3 steps below. Inspection using gauges Connect the SST gauges, a vacuum gauge (A), and a pedal depression gauge (B) as shown. Bleed the air from the SST gauges before performing the following tests. a) Checking for vacuum loss Unloaded condition 1. Start the engine. 2. Stop the engine when the vacuum gauge indicates 66.7 kPa (500 mmHg, 19.7 inHg). 3. Observe the vacuum gauge for 15 seconds. If the gauge indicates 63.4-66.6 kPa (475-500 mmHg, ,, 18.7-19.7 inHg), the unit is operating. Gartner Banana

WARNING LIGHT AND SENDER UNIT T OHMMETER Washer Level Indicator lnspection 1. Disconnect the connector from the washer level sensor. 2. Jump terminal-wire L (harness side) to a body ground. 3. Start the engine and check that the WASHER indicator illuminates. 4. If there is no illumination, check the bulb, wiring harness, and sensor. Replace or repair as necessary. Washer Level Sensor lnspection 1. Connect the sensor connector (sensor side) to an ohm- meter. 2. Move the sensor float up and down. 3. Verify that there is continuity when the float is at the low- est point. BRAKE FLUID LEVEL SENSOR lnspection 1. Check for continuity of the sensor. 2. If continuity is not as specified, replace the level sensor. Float level Below MIN Above MIN BUCKLE SWITCt Continuity Yes No OHMMETER -1 PARKING BRAKE SWITCH lnspection 1. Disconnect the parking brake switch connector. 2. Check for continuity between the switch connector and ground. I Lever I Continuity I 3. If continuity is not as specified, adjust or replace the parking brake switch. (Refer to section P.) Pulled one notch Released BUCKLE SWITCH lnspection 1. Disconnect the buckle switch connector 2. Check for continuity of the switch. Yes No Seat belt I Continuity Seat belt buckled Seat belt unbuckled No Yes 3. If continuity is not as specified, replace the buckle switch. Gartner Banana

LIGHTING SYSTEM T Symptom: Daytime running lights (DRL) do not illuminate. (Turn signals function normally.) DRL operate with engine running and following switches are off: Headlight switch Turn signal switch (Selected turn signal light flashes, other light remains illumi- nated) Hazard warning switch Parking brake switch (Parking brake released) Step 1 1. Position the vehicle on a flat surface and block the wheels to prevent vehicle movement. 2. Turn the ignition switch to ON. 3. Measure the voltage at the following terminal wires of the DRL control unit. 4. If correct, replace the DRL control unit. B+: Battery positive voltage Step 2 1. Disconnect the parking brake switch connector. 2. Check for continuity between the terminal of the switch and a body ground. Terminal J (L) u Connected to WIPER 20A fuse I(B) B (R) C (WIR) Parking brake lever Pulled one notch Continuity Yes Released Test condition Constant GND Parking brake switch Headlight switch No I 3. If not as specified, adjust or replace the parking brake switch. 4. If correct, repair wiring harness. (DRL control unit - Parking brake switch) Specification B+ Constant Parking brake released Headlight switch off Action Repair wiring harness (WIPER 20A - DRL control unit) Other B+ Other Repair wiring harness (DRL control unit - GND) Go to Step 2 Go to Step 3 Gartner Banana