Code No. P0153: Left Bank Oxygen Sensor (front) Circuit Slow Response
OPERATION
- The sensor signal is inputted to the engine-ECU (terminal
No. 38) from the left bank oxygen sensor (front) output terminal (terminal No. 4).
- The left bank oxygen sensor (front) (terminal No. 2) is earthed with engine-ECU
(terminal No. 39).
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 JUDGMENT
Check Conditions
- Engine coolant temperature is higher than 50°C.
- Engine speed is 1,250 - 3,500 r/min.
- Volumetric efficiency is 25 - 65 %.
- Under the closed loop air/fuel control.
- The accelerator pedal is open.
- Short-term fuel trim is -25 to +25 %.
- More than 2 seconds have elapsed after the abovementioned conditions have been met.
- The engine-ECU monitors for this condition for 5 cycles of 12 seconds each during
the drive cycle.
- The average of the left bank oxygen sensor (front) rich/lean switching frequency
is less than 11 times per 12 seconds.
PROBABLE CAUSES
- Failed left bank oxygen sensor (front)
- Loose connector contact
- Failed engine-ECU
DIAGNOSIS PROCEDURE |
STEP 1. M.U.T.-III data list |
|
Q.
Is the check result normal?
|
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection
Service Points - How to Cope with Intermittent Malfunctions ). |
|
Go to Step 2 . |
|
STEP 2. Check left bank oxygen sensor (front) itself. |
Q.
Is the check result normal?
|
Go to Step 3 . |
|
Replace the left bank oxygen sensor (front). |
|
STEP 3. Connector check: B-40 left bank oxygen sensor (front) connector and B-29 engine-ECU connector |
Q.
Are the check results normal?
|
Go to Step 4 . |
|
Repair or replace the connector. |
|
STEP 4. M.U.T.-III data list |
|
Q.
Is the check result normal?
|
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection
Service Points - How to Cope with Intermittent Malfunctions ). |
|
Replace the engine-ECU. |
|