P0134
DTC P0134: Heated Oxygen Sensor Circuit No Activity DetectedHeated Oxygen Sensor Circuit No Activity Detected (sensor 1) Circuit
- Refer to, DTC P0130 Heated Oxygen Sensor (front) Circuit.
- Refer to, DTC P0201, P0202, P0203, P0204 - Injector Circuit.
CIRCUIT OPERATION
- Refer to, DTC P0130 Heated Oxygen Sensor (front) Circuit.
- Refer to, DTC P0201, P0202, P0203, P0204 - Injector Circuit.
TECHNICAL DESCRIPTION
- The ECM effects air/fuel ratio feedback control in accordance with the signals from the heater oxygen sensor (front).
- If the heated oxygen sensor (front) has deteriorated, corrections will be made by the heated oxygen sensor (rear).
- DTC P0134 becomes stored in memory if a failure is detected in the above air/fuel ratio feedback control system.
DESCRIPTIONS OF MONITOR METHODS
- Heated oxygen sensor (front) output voltage does not cross 0.5 volt within specified period.
MONITOR EXECUTION
- Continuous
MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)
Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
- Misfire monitor
Sensor (The sensor below is determined to be normal)
- Volume airflow sensor
- Engine coolant temperature sensor
- Intake air temperature sensor
- Barometric pressure sensor
- Throttle position sensor
DTC SET CONDITIONS
Logic Flow Chart:
Logic Flow Chart
Check Conditions
- 20 seconds or more have passed since the engine starting sequence was completed.
- Engine coolant temperature is higher than 7 degrees C (44.6 degrees F).
- Engine speed is higher than 1,200 r/min.
- Volumetric efficiency is higher than 30 percent.
- Throttle position sensor output voltage is lower than 4 volts.
- Except while fuel is being shut off.
- Monitoring time: 30 seconds.
Judgment Criterion
- Heated oxygen sensor (front) output voltage does not get across 0.5 volt within about 30 seconds.
OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 11. OBD-II Drive Cycle Pattern Lists
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
- Heated oxygen sensor (front) deteriorated.
- Harness damage in heated oxygen sensor (front) output line.
- Heated oxygen sensor (rear) deteriorated.
NOTE:
- When the heated oxygen sensor (front) begins to deteriorate, the heated oxygen sensor output voltage will deviate from the voltage when the sensor was new (normally 0.5 volt at stoichiometric ratio). This deviation will be corrected by the heated oxygen sensor (rear).
- If the heated oxygen sensor (rear) responds poorly because it has deteriorated, it will improperly correct the heated oxygen sensor (front). Thus, even when closed loop control is being effected, the fluctuation of the heated oxygen sensor (front) output voltage decreases, without intersecting with 0.5 volt. As a result, there is a possibility of DTC P0134 becoming registered.
- Open circuit in injector.
- Harness damage in injector circuit.
- Connector damage.
- ECM failed.
- Exhaust leak.
- Air drawn in from gaps in gasket, seal, etc.
- Incorrect fuel pressure.
DIAGNOSIS
Required Special Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991911: Main Harness B
- MD998464: Test Harness
STEP 1. Using scan tool MB991958, check data list item 59: Heated Oxygen Sensor (rear).
CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
1. Connect scan tool MB991958 to the data link connector.
2. Start the engine and run at idle.
3. Set scan tool MB991958 to the data reading mode for item 59, Heated Oxygen Sensor (rear).
- Warm up the engine. When the engine is revved, the output voltage should repeat 0 volt and 0.6 to 1.0 volt alternately.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES: Go to Step 2.
NO: Refer to, DTC P0136 - Heated Oxygen Sensor Circuit (sensor 2), DTC P0137 - Heated Oxygen Sensor Circuit Low Voltage (sensor 2) , DTC P0138 - Heated Oxygen Sensor Circuit High Voltage (sensor 2) , DTC P0139 - Heated Oxygen Sensor Circuit Slow Response (sensor 2).
STEP 2. Check for exhaust leaks.
Q: Are there any abnormalities?
YES: Repair it. Then go to Step 12.
NO: Go to Step 3.
STEP 3. Check for intake system vacuum leaks.
Q: Are there any abnormalities?
YES: Repair it. Then go to Step 12.
NO: Go to Step 4.
STEP 4. Check harness connector B-113 at the heated oxygen sensor (front) for damage.
Q: Is the harness connector in good condition?
YES: Go to Step 5.
NO: Repair or replace it. Then go to Step 12.
STEP 5. Check the heated oxygen sensor (front).
1. Disconnect the heated oxygen sensor (front) connector B-113 and connect test harness special tool, MD998464, to the connector on the heated oxygen sensor (front) side.
2. Warm up the engine until engine coolant temperature reaches 80 degrees C (176 degrees F) or higher.
3. Perform a racing for 5 minutes or more with the engine speed of 4,500 r/min.
4. Connect a digital voltage meter between terminal No.2 (black clip) and terminal No.4 (white clip).
5. While repeatedly revving the engine, measure the heated oxygen sensor (front) output voltage.
Standard value: 0.6 - 1.0 volt
CAUTION:
- Be very careful when connecting the jumper wires; incorrect connection can damage the heated oxygen sensor.
- Be careful the heater is broken when voltage of beyond 8 volts is applied to the heated oxygen sensor heater.
NOTE: If the sufficiently high temperature [of approximate 400 degrees C (752 degrees F) or more] is not reached although the heated oxygen sensor is normal, the output voltage would be possibly low although the rich air/fuel ratio. Therefore, if the output voltage is low, use a jumper wire to connect the terminal No.1 (red clip) and the terminal No.3 (blue clip) of the heated oxygen sensor with the positive terminal and the negative terminal of 8 volts power supply respectively, then check again.
Q: Is the measured voltage between 0.6 and 1.0 volt?
YES: Go to Step 6.
NO: Replace the heated oxygen sensor (front). Then go to Step 12.
STEP 6. Check harness connectors B-17, B-18, B- 20, B- 22 at injector for damage.
Q: Is the harness connector in good condition?
YES: Go to Step 7.
NO: Repair or replace it. Then go to Step 12.
STEP 7. Check the injector.
1. Disconnect each injector connector.
2. Measure the resistance between injector side connector terminal No.1 and No.2.
Standard value: 2 - 3 Ohms [at 20 degrees C (68 degrees F)]
Q: Is the measured resistance between 2 and 3 Ohms [at 20 degrees C (68 degrees F)]?
YES: Go to Step 8.
NO: Replace the injector. Then go to Step 12.
STEP 8. Check harness connectors C-115, C-121 at ECM for damage.
Q: Is the harness connector in good condition?
YES: Go to Step 9.
NO: Repair or replace it. Then go to Step 12.
STEP 9. Check for harness damage between heated oxygen sensor (front) connector B-113 (terminal No.4) and ECM connector C-117 (terminal No.71).
Q: Is the harness wire in good condition?
YES: Go to Step 10.
NO: Repair it. Then go to Step 12.
STEP 10. Check for harness damage between injector connectors B-17, B-18, B-20, B-22 and ECM connector C-121.
a. Check the harness wire between injector connector B-22 (terminal No.2) and ECM connector C-121 (terminal No.1) at No.1 cylinder.
b. Check the harness wire between injector connector B-20 (terminal No.2) and ECM connector C-121 (terminal No.9) at No.2 cylinder.
c. Check the harness wire between injector connector B-18 (terminal No.2) and ECM connector C-121 (terminal No. 24) at No.3 cylinder.
d. Check the harness wire between injector connector B-17 (terminal No.2) and ECM connector C-121 (terminal No.2) at No.4 cylinder.
Q: Is the harness wire in good condition?
YES: Go to Step 11.
NO: Repair it. Then go to Step 12.
STEP 11. Check the fuel pressure.
Refer to On-Vehicle Service - Fuel Pressure Test Testing and Inspection.
Q: Is the fuel pressure normal?
YES: Replace the ECM. Then go to Step 12.
NO: Repair it. Then go to Step 12.
STEP 12. Test the OBD-II drive cycle.
1. Carry out a test drive with the drive cycle pattern. Refer to, Diagnostic Function - OBD-II Drive Cycle - Pattern 11. OBD-II Drive Cycle Pattern Lists
2. Check the diagnostic trouble code (DTC).
Q: Is DTC P0134 set?
YES: Retry the troubleshooting.
NO: The inspection is complete.