Troubleshooting
DTC P0134 OXYGEN SENSOR CIRCUIT NO ACTIVITY DETECTED (BANK 1 SENSOR 1)CIRCUIT DESCRIPTION
To obtain a high purification rate of the CO, HC and NOx components of the exhaust gas, a three-way catalytic converter is used. For the most efficient use of the three-way catalytic converter, the air-fuel ratio must be precisely controlled so that it is always close to the stoichiometric air-fuel ratio.
The air fuel ratio sensor has the characteristic that it provides output voltage* being approximately proportional to the existing air-fuel ratio. The air fuel ratio sensor output voltage* is used to provide feedback for the ECM to control the air-fuel ratio.
By the air fuel ratio sensor output, the ECM can determine the deviation amount from the stoichiometric air-fuel ratio and control the proper injection time immediately. If the air fuel ratio sensor is does not function, ECM is unable to perform the accurate air-fuel ratio control.
The air fuel ratio sensor is equipped with a heater which heats the zirconia element. The heater is controlled by the ECM. When the intake air volume is low (the temperature of the exhaust gas is low), the current flows to the heater to heat the sensor for the accurate oxygen concentration detection.
*: The voltage value changes at the inside of the ECM only.
DTC Detecting Condition:
HINT: This DTC is recorded when air fuel ratio sensor heater is in a malfunction, although the caption is oxygen sensor.
HINT:
- After confirming DTC P0134 and P0154, use the OBD II scan tool or hand-held tester to check voltage output of the air fuel ratio sensor (bank 1,2 sensor 1) from the "DIAGNOSIS/ENHANCED OBD II/DATA LIST/ALL DATA".
- The ECM controls the voltage of the AFR+, AFL+, AFR- and AFL- terminals of the ECM to the fixed voltage. Therefore, it is impossible to check the air fuel ratio sensor output voltage without the OBD II scan tool or hand-held tester.
- OBD II scan tool (excluding hand-held tester) displays the one fifth of the air fuel ratio sensor output voltage which is displayed on the hand-held tester.
CONFIRMATION DRIVING PATTERN
1. Connect the hand-held tester to the DLC3. (*1)
2. Switch the hand-held tester from the normal mode to the check mode.(*1)
3. Start the engine and warm it up with all the accessory switches OFF.(*2)
4. Drive the vehicle at 60 - 120 km/h (38 - 75 mph) and engine speed at 1,400 - 3,200 rpm for 3 - 5 min.(*3)
HINT: If a malfunction exists, the MIL will light up during step. (*3)
NOTE: If the conditions in this test are not strictly followed, detection of the malfunction will not be possible.
If you do not have a hand-held tester, turn the ignition switch OFF after performing steps (*2) and (*3), then perform steps (*2) and (*3) again.
Wiring Diagram:
Step 1:
Step 2:
Step 2 (continued) - 4:
Step 5:
Step 6:
Step 7 - 11:
Step 12 - 17:
Step 18 - 20:
INSPECTION PROCEDURE
HINT:
Hand-held tester only:
The narrowing down the trouble area is possible by performing ACTIVE TEST of the following "A/F CONTROL" (oxygen sensor or another can be distinguished).
a. Perform ACTIVE TEST by hand-held tester (A/F CONTROL).
HINT: "A/F CONTROL" is an ACTIVE TEST which changes the injection volume to -12.5 % or +25 %.
1. Connect the hand-held tester to the DLC3 on the vehicle.
2. Turn the ignition switch ON.
3. Warm up the engine with the engine speed at 2,500 rpm for approx. 90 sec.
4. Select the item "DIAGNOSIS/ENHANCED OBD II/ACTIVE TEST/ A/F CONTROL".
5. Perform "A/F CONTROL" when idle condition (press the right or left button).
Result: Air fuel ratio sensor and oxygen sensor reacts in synchronizing with increase and decrease of injection volume (+25 % rich output: 1 V, -12.5 % lean output: 0 V)
NOTE: However, there is a few second delay in the sensor 1 (front air fuel ratio sensor) output. And there is about 20 seconds delay in the sensor 2 (rear oxygen sensor).
The following procedure of A/F CONTROL enable that to check its output (show its graph indication) of air fuel ratio sensor and oxygen sensor.
To display the graph indication. Select and push the "YES or NO" button 2 data "AFS B1S1 and O2S B1S2" or "AFS B2S1 and O2S B2S2" and press button "4" after selecting "ACTIVE TEST /A/F CONTROL/USER DATA".
HINT:
- If DTC P0134 is displayed, check Bank 1 Sensor 1 circuit.
- If DTC P0154 is displayed, check Bank 2 Sensor 1 circuit.
- Bank 1 refers to the bank that includes cylinder No.1.
- Bank 2 refers to the bank that includes cylinder No.2.
- If the vehicle runs out of fuel, the air-fuel ratio is LEAN and DTC P0134 and P0154 are recorded. The MIL then comes on.
- Read freeze frame data using the hand-held tester or the OBD II scan tool, as freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was lean or rich, etc. at the time of the malfunction.
CHECK FOR INTERMITTENT PROBLEMS
Hand-held tester only:
By putting the vehicle's ECM in the check mode, the 1 trip detection logic is possible instead of 2 trip detection logic and sensitivity the to detect open circuits is increased. This makes it easier to detect intermittent problems.
1. Clear the DTC.
2. Set the check mode.
3. Perform a simulation test.
4. Check the connector and terminal.
5. Handle the connector.