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Home › Mazda › 2005 › Tribute s, FWD › Repair and Diagnosis › Engine Performance › Symptom Troubleshooting [Engine Control System] › Downstream Heated Oxygen Sensor (Ho2S)

Downstream Heated Oxygen Sensor (Ho2S)

NOTE: The following test procedures are for DTCs P1137, P1138, P1157, P1158, P2270, P2271, P2272 and P2273.
Fig 1: Downstream Heated Oxygen Sensor (HO2S) Detection Condition Possible Cause
G03723682Courtesy of MAZDA MOTORS CORP.
Fig 2: Identifying Heated Oxygen Sensor (HO2S)
G03723683Courtesy of MAZDA MOTORS CORP.
HEATED OXYGEN SENSOR INSPECTION/ACTION CHART

STEP INSPECTION ACTION
1
  • Was PCM Quick Test performed? 
 Yes If Continuous Memory Ignition (P0350-P0354) or Misfire (P0300-P0306) DTCs are received during Continuous Memory Testing, repair them first. Otherwise, go to next step.
No Perform PCM Quick Test. See PCM QUICK TEST  .
2 KOER DTCS P1137, P2270, P1157, P2272, P1138, P2271, P1139, P2273: CHECK FOR KOER DTCS
  • Key ON, Engine Running (KOER).
  • Run engine at approximately 2,000 RPM.
  • Perform KOER Self-Test.
  • Are any of the above listed DTCs present? 
 Yes Key OFF.
Go to next step.
No Key OFF.
Unable to duplicate or identify fault at this time.
3 CHECK FOR RELATED HO2S DTCS
  • Were DTCs P0132 or P0138 present during PCM Quick Test? 
 Yes See HEATED OXYGEN SENSOR (HO2S) OVER VOLTAGE  .
No Go to next step.
4 CHECK SIGNAL CIRCUIT FOR SHORT TO GROUND
  • Disconnect PCM.
  • Install Breakout Box, leave PCM disconnected.
  • Disconnect HO2S in question.
  • Measure resistance of the HO2S SIG circuit between PCM test pin T24 (DTCs P1137, P2270, P1138, P2271) or PCM test pin T25 (DTC P1157, P2272, P1158, P2273) and ground.
  • Is the resistance greater than 10K ohms? 
 Yes Go to next step.
No Repair short circuit.
Go to step 11.
5 CHECK HARNESS FOR INTERNAL SHORT
  • Use the following list to measure resistance between the appropriate PCM test pins:
    • For DTC P1137, P2270, P1138, and P2271, test pin T24 and test pins E41, T47, and B35.
    • For DTC P1157, P2272, P1158, and P2273, test pin T25 and test pins E41, T48, and B35.
  • Are the resistances greater than 10K ohms? 
 Yes For DTCs P1137, P2270, P1138, and P2271, go to next step.
For DTC P1157, P2272, P1158, and P2273, go to step 7.
No Repair short circuit.
Go to step 11.
6 CHECK HO2S-12 CIRCUITS FOR OPEN
  • Use the following list to measure resistance between the appropriate PCM test pin and the HO2S sensor connector, harness side:
    • test pin B35 and HO2S pin 2.
    • test pin T47 and HO2S pin 1
    • test pin E41 and HO2S pin 4
    • test pin T24 and HO2S pin 3.
  • Is each resistance less than 5.0 ohms? 
 Yes Go to step 8.
No Repair open circuit.
Go to step 11.
7 CHECK HO2S-22 CIRCUITS FOR OPEN
  • Use the following list to measure resistance between the appropriate PCM test pin and the HO2S sensor connector, harness side: 
    • test pin B35 and HO2S pin 2.
    • test pin T48 and HO2S pin 1
    • test pin E41 and HO2S pin 4
    • test pin T25 and HO2S pin 3.
  • Is each resistance less than 5.0 ohms? 
 Yes Go to next step.
No Repair open circuit.
Go to step 11.
8 CHECK HO2S CIRCUIT FOR VOLTAGE
  • Remove Breakout Box, connect PCM.
  • Connect any disconnected HO2S sensor(s).
  • Key ON, Engine Running (KOER).
  • Access the appropriate HO2S PID using the WDS or equivalent tester.
  • Is the voltage greater than 1.5 volts? 
 Yes Key OFF.
Go to step 10.
No Go to next step.
9 CHECK HO2S SENSOR
  • Key OFF.
  • Disconnect HO2S sensor connector in question.
  • Install a jumper wire between HO2S connector pin 2 and pin 3, harness side.
  • Key ON, Engine Running (KOER).
  • Access the appropriate HO2S PID using the WDS or equivalent tester.
  • Is the voltage greater than 1.5 volts? 
 Yes Replace the HO2S sensor in question.
See HEATED OXYGEN SENSOR (HO2S) AND CATALYST MONITOR SENSOR - 2.3L , HEATED OXYGEN SENSOR (HO2S) AND CATALYST MONITOR SENSOR - 3.0L (4V) .
Go to step 11.
No Replace PCM.
See POWERTRAIN CONTROL MODULE (PCM) .
Go to step 11.
10 CHECK FOR OVER VOLTAGE IN PCM
  • Key OFF.
  • Disconnect HO2S sensor connector in question.
  • Key ON, Engine Running (KOER).
  • Measure the voltage between the HO2S sensor connector in question, pin 4 and ground.
  • Measure the voltage between the HO2S sensor connector in question, pin 3 and ground.
  • Are the voltages below 1.5 volts? 
 Yes Replace the HO2S sensor in question.
See HEATED OXYGEN SENSOR (HO2S) AND CATALYST MONITOR SENSOR - 2.3L , HEATED OXYGEN SENSOR (HO2S) AND CATALYST MONITOR SENSOR - 3.0L (4V) .
Go to next step.
No Replace PCM.
See POWERTRAIN CONTROL MODULE (PCM) .
Go to next step.
11 VERIFY TROUBLESHOOTING OF DTCs COMPLETED
  • Perform PCM Quick Test. See PCM QUICK TEST  .
  • Is any DTC present? 
 Yes Go to applicable DTC inspection.
No Troubleshooting complete.
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