P0136
DTC P0136 HO2S CIRCUIT (BANK 1/SENSOR 2)Component Location:
GENERAL DESCRIPTION
The rear heated oxygen sensor is mounted on the rear side of the Catalytic Converter (warm-up catalytic converter) or in the rear exhaust pipe, which is able to detect catalyst efficiency. The rear heated oxygen sensor (HO2S) produces a voltage between 0 V and 1 V. This rear heated oxygen sensor is used to estimate the oxygen Storage capability. If a catalyst has good conversion properties, the oxygen fluctuations are smoothed by the oxygen storage capacity of the catalyst. If the conversion provided by the catalyst is low due to aging, poisoning or misfiring, then the oxygen fluctuations are similar to signals from the front oxygen sensor.
DTC DESCRIPTION
ECM sets DTC P0136 if the ECM detects that the rear HO2S signal circuit is open.
DTC Detecting Condition:
Schematic Diagram:
Signal Waveform And Data Part 1:
Signal Waveform And Data Part 2:
MONITOR DTC STATUS
1. Connect scan tool and select "Diagnostic Trouble Codes (DTCs)" mode.
2. Press F4 (DTAL) to select DTC information from the DTCs menu.
3. Confirm that "DTC Readiness Flag" indicates "Complete". If not, drive the vehicle within conditions noted in the freeze frame data or enable conditions.
4. Read "DTC Status" parameter.
5. Is parameter displayed "History (Not Present) fault"?
NOTE
- History (Not Present) fault : DTC occurred but has been cleared.
- Present fault : DTC is occurring at present time.
YES - Fault is intermittent caused by poor contact in the sensor's and/or ECM's connector or was repaired and ECM memory was not cleared. Thoroughly check connectors for loose or poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure
NO - Go to next step as below
GROUND CIRCUIT INSPECTION
1. Ignition "OFF".
2. Disconnect HO2S connectors.
3. Measure resistance between terminals 2 of the sensor harness connector and chassis ground.
Specification : Approx. 0 ohm
4. Is resistance within the specification?
YES - Go to "Signal circuit inspection" procedure
NO - Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure
NOTE: HO2S must have a clean air reference to function properly The air is obtained by way of the sensor wire(s). Do not attempt to repair the wire(s), connector, or the terminals.
SIGNAL CIRCUIT INSPECTION
1. Ignition "ON" & Engine "OFF".
2. Measure voltage between terminal 1 of the sensor harness connector and chassis ground.
Specification : Approx. 0.4 - 0.5 V
3. Is voltage within the specification?
YES - Go to next step as below
NO - Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure HO2S must have a clean air reference to function properly The air is obtained by way of the sensor wire(s). Do not attempt to repair the wire(s), connector, or the terminals.
TERMINAL AND CONNECTOR INSPECTION
1. Many malfunctions in the electrical system are caused by poor harness(es) and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
3. Has a problem been found?
YES - Repair as necessary and go to "Verification of Vehicle Repair" procedure
NO - Go to next step as below
COMPONENT INSPECTION
1. With ignition "OFF", reconnect the HO2S connector.
2. Warm up the engine to normal operating temperature and let it idle.
3. Connect Scantool and monitor the O2 SNSR V0L.- B1/S2 parameter on the Scantool data list.
Specification : Above 0.6 V at idle
4. Is sensor data near the specified value?
YES - Check for Door connection between ECM and component: backed out terminal, improper mating, broken locks or poor terminal to wire connection. Repair as necessary and go to "Verification of Vehicle Repair" procedure
NO - Check HO2S for contamination, deterioration, or damage. Substitute with a known-good HO2S and check for proper operation. If the problem is corrected, replace HO2S and then go to "Verification of Vehicle Repair" procedure
VERIFICATION OF VEHICLE REPAIR
After a repair, it is essential to verify that the fault has been corrected.
1. Connect scan tool and select "Diagnostic Trouble Codes (DTCs)" mode
2. Press F4 (DTAL) and confirm that "DTC Readiness Flag" indicates "Complete". If not, drive the vehicle within conditions noted in the freeze frame data or enable conditions.
3. Read "DTC Status" parameter.
4. Is parameter displayed "History (Not Present) fault"?
YES - System performing to specification at this time. Clear the DTC
NO - Go to the applicable troubleshooting procedure.