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Home >> Mazda >> 2021 >> 3 Base >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> On-Board Diagnostic - Engine Control System (VINS 7, L, M) (1 Of 4) >> DTC P0140-00: Ho2S Circuit No Activity Detected >> Troubleshooting Diagnostic Procedure >> Intention of troubleshooting procedure

Intention of troubleshooting procedure

TROUBLESHOOTING DIAGNOSTIC PROCEDURE

Step Inspection Results Action
1 PURPOSE: INSPECT HO2S CONNECTOR FOR MALFUNCTION
  • Inspect the applicable connector and terminal. (See CONNECTOR INSPECTION .)
  • Are the connector and terminal normal?
Yes Go to the next step.
No Repair or replace the malfunctioning location and perform the repair completion verification.
2 PURPOSE: INSPECT PCM CONNECTOR FOR MALFUNCTION
  • Inspect the applicable connector and terminal. (See CONNECTOR INSPECTION .)
  • Are the connector and terminal normal?
Yes Go to the next step.
No Repair or replace the malfunctioning location and perform the repair completion verification.
3 PURPOSE: INSPECT HO2S SIGNAL CIRCUIT FOR SHORT TO GROUND
  • Inspect the applicable circuit for a short to ground. (See CIRCUIT INSPECTION .)
  • Is the circuit normal?
Yes Go to the next step.
No Repair or replace the malfunctioning location and perform the repair completion verification.
4 PURPOSE: INSPECT HO2S SIGNAL CIRCUIT FOR OPEN CIRCUIT
  • Inspect the applicable circuit for open circuit. (See CIRCUIT INSPECTION .)
  • Is the circuit normal?
Yes Go to the next step.
No Repair or replace the malfunctioning location and perform the repair completion verification.
5 PURPOSE: VERIFY IF HO2S IS INSTALLED CORRECTLY
Yes Go to the next step.
No Correctly install the HO2S and perform the repair completion verification.
(See HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION [(VIN M) (US)] .)
(See HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION [(VIN 7 & VIN L) (US)] .)
6 PURPOSE: INSPECT HO2S FOR MALFUNCTION
Yes Go to the next step.
No Repair or replace the malfunctioning location and perform the repair completion verification.
(See HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION [(VIN M) (US)] .)
(See HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION [(VIN 7 & VIN L) (US)] .)
7 PURPOSE: VERIFY IF MALFUNCTION RELATED TO EMISSION SYSTEM AFFECTS HO2S SIGNAL
  • Verify the exhaust gas leakage from the exhaust system. (between A/F sensor and HO2S)
  • Is there any malfunction?
Yes Repair or replace the malfunctioning location and perform the repair completion verification.
No Go to the next step.
8 PURPOSE: VERIFY IF MALFUNCTION RELATED TO ENGINE COMPRESSION AFFECTS DIAGNOSTIC RESULTS
Yes Go to the next step.
No Replace or overhaul the engine and perform the repair completion verification.
9 PURPOSE: INSPECT HO2S HEATER FOR MALFUNCTION
Yes Go to the next step.
No Repair or replace the malfunctioning location and perform the repair completion verification.
(See HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION [(VIN M) (US)] .)
(See HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION [(VIN 7 & VIN L) (US)] .)
Repair completion verification 1 PURPOSE: VERIFY THAT VEHICLE IS REPAIRED
  • Install/connect the part removed/disconnected during the troubleshooting procedure.
  • Clear the DTC recorded in the memory. (See CLEARING DTC .)
  • Replicate the vehicle conditions at the time the DTC was detected using the following procedure.
  • Perform the DTC inspection for the PCM. (See DTC INSPECTION .)
  • Is the same Pending DTC present?
Yes Refer to the controller area network (CAN) malfunction diagnosis flow to inspect for a CAN communication error.
(See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW (US) .)
If the CAN communication is normal, perform the diagnosis from Step 1.
  • If the malfunction recurs, replace the PCM, then go to the next step.

(See PCM REMOVAL/INSTALLATION [(VIN M) (US)] .) (See PCM REMOVAL/INSTALLATION [(VIN 7 & VIN L) (US)] .)
No Go to the next step.
Repair completion verification 2 PURPOSE: VERIFY IF OTHER DTCs DISPLAYED
  • Perform the DTC inspection. (See DTC INSPECTION .)
  • Are any other DTCs displayed?
Yes Repair the malfunctioning location according to the applicable DTC troubleshooting.
No DTC troubleshooting completed.