Code No. P0152: Left Bank Oxygen Sensor (front) Circuit High Voltage

OPERATION

• The sensor signal is inputted to the engine-ECU connector terminal O2FL from the left bank oxygen sensor (front) output terminal.
  
• The left bank oxygen sensor (front) is earthed with engine-ECU connector terminal O2VE.
  
• The engine-ECU connector terminal O2VE applies an offset voltage of 0.5 V to the left bank oxygen sensor (front).
  

FUNCTION

• The left bank oxygen sensor (front) converts the concentration of oxygen in the exhaust emission into a voltage and inputs the signal to the engine-ECU.
  
• When the air-fuel ratio is richer than the theoretical air-fuel ratio, the left bank oxygen sensor (front) outputs a voltage of about 1 V. When it is leaner than the theoretical air-fuel ratio, it outputs a voltage of about 0 V.
  
• In response to the signal, the engine-ECU controls the fuel injection amount so that the air-fuel ratio can be equivalent to the theoretical air-fuel ratio.
  

TROUBLE JUDGEMENT

• More than 2 seconds have passed since the engine starting sequence was completed.
  
• Left bank oxygen sensor (front) offset voltage is more than 0.4 V and is less than 3.8 V.
  

• Left bank oxygen sensor (front) output voltage is less than 1.2 V for 2 seconds.
  

FAIL-SAFE AND BACKUP FUNCTION

• None
  

PROBABLE CAUSES

• Failed left bank oxygen sensor (front)
  
• Short circuit in left bank oxygen sensor (front) circuit or loose connector contact
  
• Failed engine-ECU
  

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

	Go to Step 2.

	Go to Step 3.

	Repair the connector(s) or wiring harness.

	Go to Step 4.

	Repair the connector(s) or wiring harness.

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

	Replace the engine-ECU.