1A
DTC P0131 / P0132: O2 Sensor (HO2S) Circuit Low Voltage / High Voltage (Sensor-1)
Wiring Diagram
1. Shield wire 4. “IG” fuse 7. To HO2S-2 heater 10. Relay box
2. Ignition switch 5. HO2S-1 8. ECM 11. “IGN1” fuse
3. Circuit fuse box 6. Heater 9. To other sensor      
DTC Detecting Condition and Trouble Area
DTC detecting condition Trouble area
DTC P0131:
Maximum HO2S voltage is less than 0.6 V
(2 driving cycle detection logic)
DTC P0132:
Minimum HO2S voltage is 0.3 V or more
(*2 driving cycle detection logic, monitoring once/1 driving)
• HO2S-1 circuit
• HO2S-1
• Fuel system
• ECM
• Fuel shortage
• Exhaust system
• Air intake system
DTC Confirmation Procedure
WARNING:
• When performing a road test, select a place where there is no traffic or possibility of a traffic accident and be very careful during testing to avoid occurrence of an accident.
• Road test should be carried out with 2 persons, a driver and a tester, on a level road.
NOTE:
Check to make sure that the following conditions are satisfied when using this “DTC Confirmation Procedure”.
• Intake air temperature at engine start: –10 °C (14 °F) to 80 °C (176 °F)
• Intake air temperature: –10 °C (14 °F) to 70 °C (158 °F)
• Engine coolant temperature: 70 °C (158 °F) to 150 °C (302 °F)
• Altitude (barometric pressure): 2400 m, 8000 ft or less (560 mmHg, 72 kPa or more)
1) With ignition switch turned OFF, connect scan tool.
2) Turn ON ignition switch and clear DTC using scan tool.
3) Start engine and warm up to normal operating temperature.
4) Drive vehicle at 40 mph (60 km/h) or higher. (engine speed: 2500 – 3000 r/min.)
5) Keep above vehicle speed for 6 min. or more. (Throttle valve opening is kept constant in this step.)
6) Release accelerator pedal and with engine brake applied, keep vehicle coasting (with fuel cut for 3 sec. or more) and then stop vehicle.
7) Check DTC and pending DTC.
DTC Troubleshooting
Step Action YES NO
1
Was “Engine and Emission Control System Check” performed?
Go to Step 2.
Go to Engine and Emission Control System Check:M13A with VVT .
2
Is there DTC(s) other than HO2S-1?
Go to applicable DTC diag. flow.
Go to Step 3.
3
HO2S-1 signal check
1) Connect scan tool to DLC with ignition switch turned OFF.
2) Warm up engine to normal operating temperature and keep it at 2000 r/min. for 60 sec.
3) Repeat racing engine (Repeat depressing accelerator pedal 5 to 6 times continuously and take foot off from pedal to enrich and enlean A/F mixture).
Does HO2S-1 output voltage deflect between below 0.3 V and over 0.6 V repeatedly?
Intermittent trouble. Check for intermittent referring to Intermittent and Poor Connection Inspection . If they are OK, go to Step 9.
Go to Step 4.
4
HO2S-1 ground check
1) Disconnect connector from HO2S-1 with ignition switch turned OFF.
2) Check for proper connection to HO2S-1 connector at “PNK/BLK”, “RED”, “BLK/ WHT” and “BLK/BLU” wire terminals.
3) If connections are OK, measure resistance between “BLK/BLU” wire terminal of HO2S-1 connector and engine ground.
Is resistance less than 5 Ω?
Go to Step 5.
“BLK/BLU” wire open or high resistance circuit. Poor “E119-28” terminal connection.
Faulty ECM ground. If they are OK, substitute a known-good ECM and recheck.
5
Wire circuit check
1) Turn OFF ignition switch.
2) Measure resistance between “RED” wire terminal of HO2S-1 connector and “E119-11” wire terminal of ECM connector.
Is resistance less than 5 Ω?
Go to Step 6.
“RED” wire high resistance circuit or open circuit. Poor “E119-11” terminal connection.
Faulty ECM ground. If they are OK, substitute a known-good ECM and recheck.
6
Wire circuit check
1) Disconnect connectors from ECM with ignition switch turn OFF.
2) Measure resistance between “RED” wire terminal of HO2S-1 connector and body ground.
Is resistance infinity?
Go to Step 7.
“RED” wire shorted to ground circuit.
7
HO2S-1 signal circuit check
1) Measure voltage between “RED” wire terminal of HO2S-1 connector and vehicle body ground.
Is voltage 0 V?
Go to Step 8.
“RED” wire shorted to other circuits.
8
HO2S-1 heater circuit check
1) Check HO2S-1 heater circuit referring to DTC P0031 / P0032: HO2S Heater Control Circuit Low / High (Sensor-1):M13A with VVT .
Is circuit in good condition?
Go to Step 9.
Repair or replace it.
9
Exhaust system check
1) Check exhaust system for exhaust gas leakage.
Is it OK?
Go to Step 4 in DTC P0171 / P0172: Fuel System Too Lean / Rich:M13A with VVT .
If it is in good condition, go to Step 10.
Repair exhaust system for leakage.
10
Air intake system check
1) Check air intake system for clog or leak.
Is it OK?
Check HO2S-1 referring to Heated Oxygen Sensor (HO2S-1 and HO2S-2) Heater On-Vehicle Inspection:M13A .
If it is in good condition, substitute a known-good ECM and recheck.
Repair or replace.
NOTE:
Upon completion of inspection and repair work, perform “DTC Confirmation Procedure” and confirm that the trouble has been corrected.