DTC P0134 [LF, L3]


DTC P0134	Front HO2S circuit no activity detected
DETECTION CONDITION	• The PCM monitors the input voltage from front the HO2S when the following conditions are met. If the input voltage from the sensor never exceeds 0.55 V for 83.2 s, the PCM determines that the sensor circuit is not activated. MONITORING CONDITIONS - HO2S, HO2S heater and TWC repair verification drive mode - The following conditions are met: • The engine speed is above 1,500 rpm. • The engine coolant temperature is above 80 °C {176 °F}. Diagnostic support note • This is a continuous monitor (CCM). • The MIL illuminates if the PCM detects the above malfunction condition in two consecutive drive cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM. • The PENDING CODE is available if the PCM detects the above malfunction condition during first drive cycle. • The FREEZE FRAME DATA is available. • The DTC is stored in the PCM memory.
POSSIBLE CAUSE	• Front HO2S deterioration • Front HO2S heater malfunction • Leakage in the exhaust system • Open or short to ground circuit between front HO2S terminal A and the PCM terminal 1AB • Insufficient compression • Engine malfunction


STEP	INSPECTION		ACTION
1	PERFORM DTC CONFIRMATION PROCEDURE • Perform the DTC CONFIRMATION PROCEDURE. (See DTC CONFIRMATION PROCEDURE [LF, L3].) • Is the same DTC present?	Yes	Go to the next step.
1		No	Intermittent concern exists. Go to the INTERMITTENT CONCERN TROUBLESHOOTING procedure. (See INTERMITTENT CONCERN TROUBLESHOOTING [LF, L3].)
2	VERIFY RELATED PENDING AND STORED DTCs Note • If a fuel monitor DTC, DTC P0131or P0132 is retrieved, ignore it until P0134 is fixed. • Turn the ignition switch to the OFF position, then ON (Engine off). • Verify pending and stored DTCs using the WDS or equivalent. • Are any other DTCs present?	Yes	Go to the applicable DTC troubleshooting procedures.
2		No	Go to the next step.
3	IDENTIFY TRIGGER DTC FOR FREEZE FRAME DATA • Is DTC P0134 displayed in the FREEZE FRAME DATA?	Yes	Go to the next step.
3		No	Go to the troubleshooting procedures for the DTC in FREEZE FRAME DATA. (See DTC TABLE [LF, L3].)
4	VERIFY CURRENT INPUT SIGNAL STATUS • Warm up the engine. • Access the O2S11 PID using the WDS or equivalent. • Verify the PID while racing the engine (in NEUTRAL (MTX) or PARK (ATX)). • Is the PID reading normal? - More than 0.55 V when the accelerator pedal is suddenly depressed (rich condition). - Less than 0.55 V just after accelerator pedal is released (lean condition)	Yes	Go to step 7.
4		No	Go to the next step.
5	INSPECT INSTALLATION OF FRONT HO2S • Check if front HO2S is loosely installed. • Is the sensor installed securely?	Yes	Go to the next step.
5		No	Install the sensor securely, then go to Step 9.
6	INSPECT FOR GAS LEAKAGE FROM EXHAUST SYSTEM • Visually check if any gas leakage is found between the exhaust manifold and the front HO2S. • Is there gas leakage?	Yes	Repair or replace any malfunctioning exhaust parts, then go to Step 9.
6		No	• Inspect the following harnesses for an open or short to ground circuit, Repair or replace the wiring harness if necessary. - Front HO2S terminal A (harness-side) to the PCM terminal 1AB (harness-side) • Repair or replace the wiring harness if necessary. • If all items above are normal, replace the malfunctioning sensor. then go to Step 9.
7	INSPECT SEALING OF ENGINE COOLANT PASSAGE Warning • Removing the radiator cap when the radiator is hot is dangerous. Scalding coolant and steam may shoot out and cause serious injury. • When removing the radiator cap, wrap a thick cloth around it and turn it slowly. • Remove the radiator cap. • Implement the procedure to bleed air from the engine coolant, then run the engine at idle. • Are there small bubbles that make the engine coolant white at the filling opening? Note • Large bubbles are normal since they are due to remaining air coming out from the engine coolant passage.	Yes	Air penetrates due to poor sealing of the head gasket or other areas between the combustion chamber and the engine coolant passage. Repair or replace the malfunctioning parts, then go to Step 9.
7		No	Go to the next step.
8	INSPECT ENGINE COMPRESSION • Inspect the engine compression. (See COMPRESSION INSPECTION [LF, L3].) • Is it normal?	Yes	Go to the next step.
8		No	Implement the engine overhaul for repairs, then go to the next step.
9	VERIFY TROUBLESHOOTING OF DTC P0134 COMPLETED • Make sure to reconnect all disconnected connectors. • Turn the ignition switch to the ON position (Engine off). • Clear the DTC from the memory using the WDS or equivalent. • Perform KOER self-test. (See KOEO/KOER SELF-TEST [LF, L3].) • Is the same DTC present?	Yes	Replace the PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION [LF, L3].)
9		No	Go to the next step.
10	VERIFY AFTER REPAIR PROCEDURE • Perform the "After Repair Procedure". (See AFTER REPAIR PROCEDURE [LF, L3].) • Are any DTCs present?	Yes	Go to the applicable DTC troubleshooting. (See DTC TABLE [LF, L3].)
10		No	Troubleshooting completed.