1994 MAZDA MX-5 Workshop Manual

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

TROUBLESHOOTING If the 3 steps on page K-8 are followed, the cause of the problem should be located. Another guide to faster location of the causes of problems, the QUICK DIAGNOSIS CHART, is on page K-1 0. b In this chart, numbers are used to indicate the components that may be the cause of 22 possible prob- lems. It is necessary to check only those components indicated by numbers during each step of the trouble- shooting process to locate the cause of the problem quickly. QUICK DIAGNOSIS CHART The QUICK DIAGNOSIS CHART shows different .problems and the relationship of components that might be the cause. 1. Components indicated in the "Adjustment" row indicate the possibility that the problem may result from an incorrect adjustment. Check the adjustment of each component, and readjust if necessary. 2. Components indicated in the "Self-DiagnosisWrow are diagnosed by the Powertrain control module (Transmission) self-diagnostic function. 3. Input and output signals of the Powertrain control module (Transmission) for components indicated in the "Tester" row can be easily checked with the Engine signal Monitor. 4. Components indicated in the "Mechanical System Test" row can be checked for malfunction by the re- sults of oil pressure test. 5. Components indicated in the "Road Test" row can be checked for malfunction by the results of the road test. 6. The numbers in the chart indicate the order of inspection for detecting malfunctions. 7. Circled numbers indicate that the transmission must be removed from the vehicle. 8. The checking, adjusting, repair, and replacement procedures for components are described in the page(s) shown in the "Reference page" row. Gartner Banana

K TROUBLESHOOTING Hydraulic Electronic control Prelimi- control Powertrain system "8' svstem rieference page I I \dd I Vehicle does not move in D, S, L, or R range iccelerating Vehicle moves in N range Excessive creep Not creep at all No shift 0 0 Abnormal shift sequence 0 0 Frequent shifting 0 Shifting Excessivelv hiah or low shift point 0 0 . - No lockup I No kickdown l0k I - 1 Engine runaway or slip when \,I starting vehicle- V Slipping Engine runaway or slip when up- I I I or downshifting I I ] Excessive N to D or N to R shift 1,1 shock w I change in range I Transmission noisy in N or P Noise range Transmission noisy in D, S, L, or I 1 I R ranae I I Other .. - - ( No engine braking I Transmission overheats I I White smoke discharged from exhaust Engine will not start 10 1 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