2012 Mazda 3 L4-2.5LFACTORY OEM SERVICE PROCEDURE

Pinout Values and Diagnostic Parameters





PID/DATA monitor table (reference)

Factory service manual diagram




Factory service manual diagram




Factory service manual diagram




Factory service manual diagram




Factory service manual diagram




Factory service manual diagram




Factory service manual diagram




Factory service manual diagram




*1
Calculated value; differs from terminal voltage
*2
MTX
*3
With cruise control switch

- Following PIDs are for the ATX models. If inspects for following PIDs, PID/Data Monitor Inspection [FS5A-EL]

Without Using the M-MDS

CAUTION:
- The PCM terminal voltages vary with change in measuring conditions and vehicle conditions. Always carry out a total inspection of the input systems, output systems, and PCM to determine the cause of trouble. Otherwise, a wrong diagnosis will be made.

1. Measure the voltage at each terminal.

- If any incorrect voltage is detected, inspect the related system(s), wiring harnesses and connector(s) referring to the Action column in the terminal voltage table.

Terminal voltage table (Reference)

Factory service manual diagram




Factory service manual diagram




Factory service manual diagram




Factory service manual diagram




Factory service manual diagram




Factory service manual diagram




Factory service manual diagram




Factory service manual diagram




Factory service manual diagram




*1
With cruise control system
*2
Without advanced keyless entry and push button start system
*3
With advanced keyless entry and push button start system
*4
MTX

Inspection Using An Oscilloscope (Reference)

Cooling fan control

Factory service manual diagram




PCM terminals
- 1R(+)-body ground(-)

Oscilloscope setting
- 5 V/DIV (Y), 20 ms/DIV (X), DC range

Vehicle condition
- Idle after warm up

APP sensor No.2 signal

Accelerator pedal released

Factory service manual diagram




Accelerator pedal depressed

Factory service manual diagram





PCM terminals
- 1X(+)-body ground(-)

Oscilloscope setting
- 2.5 V/DIV (Y), 2 ms/DIV (X), DC range

Vehicle condition
- Switch the ignition to ON.

Purge control

Factory service manual diagram




PCM terminals
- 1BA(+)-body ground(-)

Oscilloscope setting
- 10 V/DIV (Y), 20 ms/DIV (X), DC range

Vehicle condition
- Idle after warm up

A/F sensor heater control

Factory service manual diagram




PCM terminals
- 2A(+)-body ground(-)

Oscilloscope setting
- 5 V/DIV (Y), 200 ms/DIV (X), DC range

Vehicle condition
- Idle (immediately after starting the engine)

HO2S heater control

Factory service manual diagram




PCM terminals
- 2B(+)-body ground(-)

Oscilloscope setting
- 5 V/DIV (Y), 1 s/DIV (X), DC range

Vehicle condition
- Idle (immediately after starting the engine)

OCV control signal

Factory service manual diagram




PCM terminals
- 2E(+)-body ground(-)

Oscilloscope setting
- 2 V/DIV (Y), 0.8 ms/DIV (X), DC range

Vehicle condition
- Idle after warm up

CMP signal

Factory service manual diagram




PCM terminals
- 2S(+)-body ground(-)

Oscilloscope setting
- 1 V/DIV (Y), 25 ms/DIV (X), DC range

Vehicle condition
- Idle after warm up

CKP signal

Factory service manual diagram




PCM terminals
- 2W(+)-body ground(-)

Oscilloscope setting
- 1 V/DIV (Y), 5 ms/DIV (X), DC range

Vehicle condition
- Idle after warm up

IGT1, IGT2, IGT3, IGT4 control

Factory service manual diagram




PCM terminals
- IGT1(ignition coil No.1): 2G(+)-body ground(-)
- IGT2(ignition coil No.2): 2K(+)-body ground(-)
- IGT3(ignition coil No.3): 2L(+)-body ground(-)
- IGT4(ignition coil No.4): 2H(+)-body ground(-)

Oscilloscope setting
- 1 V/DIV (Y), 50 ms/DIV (X), DC range

Vehicle condition
- Idle after warm up

Generator field coil control

Factory service manual diagram




PCM terminals
- 2AA(+)-body ground(-)

Oscilloscope setting
- 0.5 V/DIV (Y), 2 ms/DIV (X), DC range

Vehicle condition
- Idle after warm up

Generator output voltage

Factory service manual diagram




PCM terminals
- 2AF(+)-body ground(-)

Oscilloscope setting
- 2 V/DIV (Y), 2 ms/DIV (X), DC range

Vehicle condition
- Idle after warm up

Fuel injection (#1, #2, #3, #4) control

Factory service manual diagram




PCM terminals
- Fuel Injection No.1: 2BB(+)-body ground(-)
- Fuel Injection No.2: 2BC(+)-body ground(-)
- Fuel Injection No.3: 2BD(+)-body ground(-)
- Fuel Injection No.4: 2AZ(+)-body ground(-)

Oscilloscope setting
- 10 V/DIV (Y), 25 ms/DIV (X), DC range

Vehicle condition
- Idle after warm up

Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.

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