DTC P0135 (No.14): Heated Oxygen Sensor (HO2S) Heater Circuit Malfunction
Wiring Diagram
1. Heated oxygen sensor (HO2S) heater 2. ECM
DTC Detecting Condition and Trouble Area
DTC detecting condition Trouble area
DTC will set when A or B condition is met.
Low voltage at terminal “E115-7” when engine is running at high load.
High voltage at terminal “E115-7” when engine is running under condition other than above.
HO2S heater circuit open or shorted to ground
ECM malfunction
DTC Confirmation Procedure
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.
1) Turn ignition switch OFF.
2) Clear DTC with ignition switch ON, start engine and keep it at idle for 1 min.
3) Start vehicle and depress accelerator pedal fully for 5 sec. or longer.
4) Stop vehicle.
5) Select “DTC” mode on scan tool and check DTC.
DTC Troubleshooting
Step Action YES NO
Was “Engine and Emission Control System Check” performed?
Go to Step 2.
Check heater for operation
1) Check voltage at terminal “E115-7”.
2) Warm up engine to normal operating temperature.
3) Stop engine.
4) Turn ignition switch ON and check voltage at terminal “E115-7”. Voltage should be over 10 V.
5) Using oscilloscope, check heater signal referring to “Reference waveform No.14” in Inspection of ECM and Its Circuits:M13A without VVT .
Is duty pulse outputted as reference waveform No.14 at “E115-7” of ECM terminal?
Intermittent trouble check for intermittent referring to Intermittent and Poor Connection Inspection .
Go to Step 3.
Check heater of sensor
1) Disconnect HO2S coupler with ignition switch OFF.
2) Check for proper connection to HO2S at “BLK/WHT” and “PNK/BLK” wire terminals.
3) If OK, then check heater resistance.
Is it 5 – 6.4 Ω at 20 °C, 68 °F?
“PNK/BLK” wire open or shorted to ground or poor connection at “E115-7”.
If wire and connection are OK, substitute a known-good ECM and recheck.
Replace HO2S.