DTC P0134 [ZY, Z6]


DTC P0134	Front HO2S circuit no activity detected
DETECTION CONDITION	• The PCM monitors the input voltage from the front HO2S when the following conditions are met. If the input voltage from sensor never exceeds 0.55 V for 120 s or more, the PCM determines that sensor circuit is not activated. MONITORING CONDITIONS - HO2S, HO2S heater and TWC repair verification drive mode - Following conditions are met: • Engine speed is 1,500 rpm or more. • Engine coolant temperature is 70 °C {158 °F} or more. • Within feed-back range Diagnostic support note • This is a continuous monitor (HO2S). • 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. • PENDING CODE is available if the PCM detects the above malfunction condition during the first drive cycle. • FREEZE FRAME DATA is available. • The DTC is stored in the PCM memory.
POSSIBLE CAUSE	• Front HO2S deterioration • Front HO2S heater malfunction • Leakage in exhaust system • Open circuit in wiring harness between front HO2S terminal A and PCM terminal 2AI • Short to GND in wiring harness between front HO2S terminal A and PCM terminal 2AI • Insufficient compression • Engine malfunction


STEP	INSPECTION		ACTION
1	VERIFY FREEZE FRAME DATA HAS BEEN RECORDED • Has FREEZE FRAME DATA been recorded?	Yes	Go to the next step.
1		No	Record the FREEZE FRAME DATA on the repair order, then go to the next step.
2	VERIFY RELATED REPAIR INFORMATION AVAILABILITY • Verify related service repair information availability. • Is any related repair information available?	Yes	Perform repair or diagnosis according to the available repair information. • If the vehicle is not repaired, go to the next step.
2		No	Go to the next step.
3	VERIFY RELATED PENDING AND STORED DTC Note • If fuel monitor DTC, DTC P0132 is retrieved, ignore it until P0134 is fixed. • Turn the ignition switch off, then to the ON position (Engine off). • Verify pending and stored DTCs using the WDS or equivalent. • Is other DTC present?	Yes	Go to appropriate DTC troubleshooting procedures. (See DTC TABLE [ZY, Z6].)
3		No	Go to the next step.
4	VERIFY CURRENT INPUT SIGNAL STATUS • Warm up the engine. • Access O2S11 PID using the WDS or equivalent. • Verify PID while racing engine (in NEUTRAL (MTX) or PARK (ATX)). • Is PID normal? - More than 0.55 V when suddenly depressing the accelerator pedal (rich condition) - Less than 0.55 V just after releasing the accelerator pedal (lean condition)	Yes	Go to step 7.
4		No	Go to the next step.
5	INSPECT INSTALLATION OF FRONT HO2S • Inspect if the front HO2S is loosely installed. • Is sensor installed securely?	Yes	Go to the next step.
5		No	Install sensor securely, then go to Step 9. (See FRONT HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION [ZY, Z6].)
6	INSPECT GAS LEAKAGE FROM EXHAUST SYSTEM • Visually inspect if there is any gas leakage between the exhaust manifold and the front HO2S. • Is there gas leakage?	Yes	Repair or replace any malfunctioning exhaust part, then go to Step 9.
6		No	• Inspect the following wiring harnesses for open circuit or short to GND in wiring harness. - Front HO2S terminal A (wiring harness-side) to PCM terminal 2AI (wiring harness-side) • Repair or replace 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 and turn it slowly. • Remove the radiator cap. • Implement procedure to bleed air from engine coolant, then idle the engine. • Is there any small bubble, which makes engine coolant white at filling opening? Note • Large bubbles are normal since they are remaining air coming out from engine coolant passage.	Yes	Air gets in from poor sealing on head gasket or other areas between combustion chamber and engine coolant passage. Repair or replace the malfunctioning part, then go to Step 9.
7		No	Go to the next step.
8	INSPECT ENGINE COMPRESSION • Inspect engine compression. (See COMPRESSION INSPECTION [ZY, Z6].) • Is it normal?	Yes	Go to the next step.
8		No	Perform engine overhaul for repairs, then go to the next step.
9	VERIFY TROUBLESHOOTING OF DTC P0134 COMPLETED • Make sure to reconnect all disconnected connectors. • Clear the DTC from the PCM memory using the WDS or equivalent. • Perform the "HO2S heater, HO2S, and TWC Repair Verification Drive Mode". (See OBD DRIVE MODE [ZY, Z6].) • Is the PENDING CODE for this DTC present?	Yes	Replace the PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION [ZY, Z6].)
9		No	Go to the next step.
10	VERIFY AFTER REPAIR PROCEDURE • Perform the "AFTER REPAIR PROCEDURE". (See AFTER REPAIR PROCEDURE [ZY, Z6].) • Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [ZY, Z6].)
10		No	DTC troubleshooting completed.