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Home >> Mazda >> 2006 >> MX-5 Miata Base >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Pcm Inspection >> Not Using the WDS or Equivalent
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Not Using the WDS or Equivalent

NOTE:
  • The PCM terminal voltage can vary with the conditions when measuring and changes due to aged deterioration on the vehicle, causing false diagnosis. Therefore determine comprehensively where the malfunction occurs among the input systems, output systems, and the PCM.
Fig 1: Identifying PCM Harness Side Connectors
G04323002Courtesy of MAZDA MOTORS CORP.
PCM TERMINALS VOLTAGE SPECIFICATION TABLE

Terminal Signal Connected to Test condition Voltage (V) Inspection item
1A - - - - -
1B Starter relay control Starter relay Under any condition Below 1.0
  • Starter relay
  • Related wiring harness
1C - - - - -
1D*2 Clutch operation CPP switch Clutch pedal depressed Below 1.0
  • CPP switch
  • Related wiring harness
Clutch pedal released B+
1E - - - - -
1F - - - - -
1G - - - - -
1H Fuel pump control Fuel pump relay Ignition switch is turned to the ON position (Engine off) and a certain period has elapsed B+
  • Fuel pump relay
  • Related wiring harness
Cranking Below 1.0
Idle Below 1.0
11 A/C A/C relay Engine running A/C operating Below 1.0
  • A/C relay
  • Related wiring harness
A/C not operating B+
1J Refrigerant pressure switch (middle) Refrigerant pressure switch (middle) Refrigerant pressure is more than the specification. (Refrigerant pressure switch (middle) is on.) Below 1.0
  • Refrigerant pressure switch (middle)
  • Related wiring harness
Refrigerant pressure is less than the specification. (Refrigerant pressure switch (middle) is off.) B+
1K - - - - -
1L - - - - -
1M Cooling fan control Cooling fan relay No.1 During test mode*3 Accelerator pedal released B+
  • Cooling fan relay No.1
  • Related wiring harness
Accelerator pedal depressed Below 1.0
1N Cooling fan control Cooling fan relay No.2 During test mode*3 Accelerator pedal released B+
  • Cooling fan relay No.2
  • Related wiring harness
Accelerator pedal depressed Below 1.0
1O - - - - -
1P MAF sensor ground MAF sensor Under any condition Below 1.0
  • Related wiring harness
1Q Main relay control Main relay Ignition switch is turned to the ON position Below 1.0
  • Main relay
  • Related wiring harness
Ignition switch off and a certain period has elapsed B+
1R Cooling fan control Cooling fan relay No.3 During test mode(3) Accelerator pedal released B+
  • Cooling fan relay No.3
  • Related wiring harness
Accelerator pedal depressed Below 1.0
1S - - - - -
1T - - - - -
1U EVAP system leak detection pump (pump) EVAP system leak detection pump Ignition switch is turned to the ON position B+
  • EVAP system leak detection pump
  • Related wiring harness
Idle. B+
1V EVAP system leak detection pump (solenoid) EVAP system leak detection pump Ignition switch is turned to the ON position B+
  • EVAP system leak detection pump
  • Related wiring harness
Idle B+
1W - - - - -
1X (2)Neutral position Neutral switch Shift lever is at neutral position Below 1.0
  • Neutral switch
  • Related wiring harness
Shift lever is not at neutral position B+
(1)Selector lever position TR switch Ignition switch is turned to the ON position P, N position Below 1.0
  • TR switch
  • Related wiring harness
Except above B+
1Y - - - - -
1Z - - - - -
1AA - - - - -
1AB Brake switch No.1 Brake switch Brake pedal depressed B+
  • Brake switch
  • Related wiring harness
Brake pedal released Below 1.0
1AC - - - - -
1AD - - - - -
1AE - - - - -
1AF Brake switch No.2 Brake switch Brake pedal depressed B+
  • Brake switch
  • Related wiring harness
Brake pedal released Below 1.0
1AG - - - - -
1AH - - - - -
1AI CAN_J. CAN related module Because this terminal is for CAN, no valid determination of terminal voltage is possible
  • Related wiring harness
1AJ APP sensor No.2 power supply APP sensor Ignition switch is turned to the ON position Approx. 5.0
  • Related wiring harness
1AK MAF MAF sensor Ignition switch is turned to the ON position Approx. 0.7
  • MAF sensor
  • Related wiring harness
Idle Approx. 1.4
1AL APP sensor No.1 power supply APP sensor Ignition switch is turned to the ON position. Approx. 5.0
  • Related wiring harness
1AM CAN_H CAN related module Because this terminal is for CAN, no valid determination of terminal voltage is possible
  • Related wiring harness
1AN - - - - -
1AO APP sensor No.1 APP sensor Ignition switch is turned to the ON position Accelerator pedal depressed Approx. 3.9
  • APP sensor
  • Related wiring harness
Accelerator pedal released Approx. 1.6
1AP APP sensor No.2 APP sensor Ignition switch is turned to the ON position Accelerator pedal depressed Approx. 3.4
  • APP sensor
  • Related wiring harness
Accelerator pedal released Approx. 1.0
1AQ Cruise control switch Cruise control switch Ignition switch is turned to the ON position ON OFF switch pressed in Approx. 0
  • Cruise control switch
  • Related wiring harness
CANCEL switch pressed in Approx. 1.1
SET/- switch pressed in Approx. 3.1
RES/+ switch pressed in Approx. 4.2
Except above Approx. 5.0
1AR Sensor ground MAF/IAT sensor Under any condition Below 1.0
  • Related wiring harness
1AS APP sensor No.1 ground APP sensor Under any condition Below 1.0
  • Related wiring harness
1AT IAT MAF/IAT sensor Ignition switch is turned to the ON position IAT is 20°C {68°F} Approx. 2.4
  • IAT sensor
  • Related wiring harness
IAT is 60°C {140°F} Approx. 0.9
1AU Refrigerant pressure switch (high, low) Refrigerant pressure switch (high, low) Ignition switch is turned to the ON position A/C operating Below 1.0
  • Refrigerant pressure switch (high, low)
  • Related wiring harness
A/C not operating B+
1AV APP sensor No.2 ground APP sensor Under any condition Below 1.0
  • Related wiring harness
1AW B+ Main relay Ignition switch off Below 1.0
  • Main relay
  • Battery
  • Related wiring harness
Ignition switch is turned to the ON position B+
1AX Drive-by-wire relay control Drive-by-wire relay Under any condition Below 1.0
  • Drive-by-wire relay
  • Related wiring harness
1AY Ignition switch on Ignition switch Ignition switch off Below 1.0
  • Ignition switch
  • Related wiring harness
Ignition switch is turned to the ON position B+
1AZ Ground Ground Under any condition Below 1.0
  • Related wiring harness
1BA Back-up power supply Battery (positive terminal) Under any condition B+
  • Battery
  • Related wiring harness
1BB Ground Ground Under any condition Below 1.0
  • Related wiring harness
1BC - - - - -
1BD Ground Ground Under any condition Below 1.0
  • Related wiring harness
1BE B+ Main relay Ignition switch off Below 1.0
  • Main relay
  • Related wiring harness
Ignition switch is turned to the ON position B+
1BF Drive-by-wire relay control Drive-by-wire relay Ignition switch is turned to the ON position Drive-by-wire system is malfunction Below 1.0
  • Drive-by-wire relay
  • Related wiring harness
Drive-by-wire system is normal B+
1BG - - - - -
1BH Ground Ground Under any condition Below 1.0
  • Related wiring harness
2A Throttle control (+) Throttle body (Throttle valve actuator)
  • Throttle valve actuator
  • Related wiring harness
2B Throttle control (-) Throttle body (Throttle valve actuator)
  • Throttle valve actuator
  • Related wiring harness
2C Purge control Purge solenoid valve
  • Purge solenoid valve
  • Related wiring harness
2D - - - - -
2E OCV control OCV
  • OCV
  • Related wiring harness
2F - - - - -
2G EGR valve #2 coil control EGR valve (terminal A) Idle (EGR control not operating) B+
  • EGR valve
  • Related wiring harness
2H EGR valve #4 coil control EGR valve (terminal F) Idle (EGR control not operating) B+
  • EGR valve
  • Related wiring harness
2I - - - - -
2J Variable intake air control Variable intake air solenoid valve Ignition switch is turned to the ON position Below 1.0
  • Variable intake air solenoid valve
  • Related wiring harness
Engine speed: less than 4,750 rpm Below 1.0
Engine speed: 4,750 rpm or more B+
2K EGR valve #1 coil control EGR valve (terminal E) Idle (EGR control not operating) Below 1.0
  • EGR valve
  • Related wiring harness
2L EGR valve #3 coil control EGR valve (terminal B) Idle (EGR control not operating) B+
  • EGR valve
  • Related wiring harness
2M - - - - -
2N - - - - -
2O (4) Vehicle speed VSS
  • VSS
  • Related wiring harness
2P CMP sensor ground CMP sensor Under any condition Below 1.0
  • Related wiring harness
2Q Rear HO2S Rear HO2S Idle after warm-up Alternates between 0 and 1.0
  • Rear HO2S
  • Related wiring harness
2R - - - - -
2S CMP CMP sensor
  • CMP sensor
  • Related wiring harness
2T Power steering pressure PSP switch Idle Steering wheel at straight ahead position B+
  • PSP switch
  • Related wiring harness
While turning steering wheel Below 1.0
2U Knocking (+) KS Ignition switch ON (Use digital type voltmeter, because measurement voltage will be detected less than true voltage when using analog type voltmeter) Approx. 4.3
  • KS
  • Related wiring harness
2V Knocking (-) KS Ignition switch ON (Use digital type voltmeter, because measurement voltage will be detected less than true voltage when using analog type voltmeter) Below 1.0
  • KS
  • Related wiring harness
2W CKP CKP sensor
  • CKP sensor
  • Related wiring harness
2X Ground Shield wire Under any condition Below 1.0
  • Related wiring harness
2Y - - - - -
2Z Front HO2S Front HO2S Idle after warm-up Approx. 2.4
  • Front HO2S
  • Related wiring harness
2AA - - - - -
2AB CKP sensor ground CKP sensor Under any condition Below 1.0
  • Related wiring harness
2AC - - - - -
2AD Front HO2S Front HO2S Idle after warm-up Approx. 2.8
  • Front HO2S
  • Related wiring harness
2AE - - - - -
2AF - - - - -
2AG Manifold absolute pressure MAP sensor Ignition switch is turned to the ON position (at sea level) Approx. 4.1
  • MAP sensor
  • Related wiring harness
Idle Approx. 1.2
2AH ECT ECT sensor Ignition switch is turned to the ON position ECT is 20°C {68°F} Approx. 3.0
  • ECT sensor
  • Related wiring harness
ECT is 80°C {176°F) Approx. 0.9
2AI Generator field coil control Generator (terminal D)
  • Generator
  • Related wiring harness
2AJ Generator output voltage Generator (terminal P)
  • Generator
  • Related wiring harness
2AK Throttle valve opening angle No. 1 Throttle body (TP sensor) Ignition switch is turned to the ON position Accelerator pedal depressed Approx. 4.5
  • TP sensor
  • Related wiring harness
Accelerator pedal released Approx. 1.0
2AL Throttle valve opening angle No. 2 Throttle body (TP sensor) Ignition switch is turned to the ON position Accelerator pedal depressed Approx. 0.5
  • TP sensor
  • Related wiring harness
Accelerator pedal released Approx. 4.0
2AM Constant voltage CMP sensor Ignition switch is turned to the ON position B+
  • Related wiring harness
2AN - - - - -
2AO Constant voltage (Vref) Throttle body (TP sensor) Ignition switch is turned to the ON position Approx. 5.0
  • Related wiring harness
2AP Sensor ground Throttle body (TP sensor) Under any condition Below 1.0
  • Related wiring harness
2AQ Constant voltage CKP sensor Ignition switch is turned to the ON position B+
  • Related wiring harness
2AR - - - - -
2AS - - - - -
2AT IGT4 Ignition coil (No.4 cylinders)
  • Ignition coil No.4
  • Related wiring harness
2AU Constant voltage (Vref) MAP sensor Ignition switch is turned to the ON position Approx. 5.0
  • Related wiring harness
2AV MAP sensor ground MAP sensor Under any condition Below 1.0
  • Related wiring harness
2AW IGT2 Ignition coil (No.2 cylinders)
  • Ignition coil No.2
  • Related wiring harness
2AX IGT3 Ignition coil (No.3 cylinders)
  • Ignition coil No.3
  • Related wiring harness
2AY ECT sensor ground ECT sensor Under any condition Below 1.0
  • Related wiring harness
2AZ Fuel injection (#4) Fuel injector No.4
  • Fuel injector No.4
  • Related wiring harness
2BA IGT1 Ignition coil (No.1 cylinders)
  • Ignition coil No.1
  • Related wiring harness
2BB Fuel injection (#1) Fuel injector No.1
  • Fuel injector No.1
  • Related wiring harness
2BC Fuel injection (#2) Fuel injector No.2
  • Fuel injector No.2
  • Related wiring harness
2BD Fuel injection (#3) Fuel injector No.3
  • Fuel injector No.3
  • Related wiring harness
2BE Rear HO2S heater control Rear HO2S heater Heavy load (Heater control not operating) B+
  • Rear HO2S heater
  • Related wiring harness
2BF - - - - -
2BG Front HO2S heater control Front HO2S heater
  • Front HO2S heater
  • Related wiring harness
2BH Rear HO2S ground Rear HO2S Under any condition Below 1.0
  • Related wiring harness
(1) AT
(2) MT
(3) Turn the test mode on using the WDS simulation function.
(4) MT without ABS/DSC