Wide Range Air/Fuel Ratio Sensors vs. Scan Tool
Note. PIDs $24 to $2B shall be used for linear or wide-ratio Oxygen Sensors when equivalence ratio and voltage are displayed:
PIDs $34 to $3B shall be used for linear or wide-ratio Oxygen Sensors when equivalence ratio and current are displayed:
Quotes from 2005 CAMRY SOLARA REPAIR MANUAL (RM1128U).
The Air-Fuel Ratio Sensor provides (photo)
output voltage (the voltage value changes on the inside of the ECM only) approximately equal to the existing air-fuel
ratio. The A/F sensor output voltage is used to provide feedback for the ECM to control the air-fuel ratio.With the
A/F sensor output, the ECM can determine deviation from the stoichiometric air-fuel ratio and control proper injection
time. If the A/F sensor is malfunctioning, the ECM is unable to accurately control air-fuel
If the heated oxygen sensor output voltage is 0.15 V or more but the A/F sensor voltage output is more than 3.8 V (very LEAN) for 10 seconds, DTC P2195 or DTC P2197 is set.
DATA LIST/ACTIVE TEST->:
PID "AFS B1 S1" / Minimum: 0 V, Maximum: 7.999 V / Idling 2.8 to 3.8 V / Performing INJ VOL or A/F CONTROL function of ACTIVE TEST enable the technician to check voltage output of each sensor.
ACTIVE TEST A/F CONTROL operation.
(5) Perform the A/F CONTROL operation with the engine idling. Result:
A/F sensor reacts in accordance with increase and decrease of injection volume:
Heated oxygen sensor reacts in accordance with increase and decrease of injection volume:
READ VALUE OF HAND-HELD TESTER OR OBD II SCAN TOOL (OUTPUT VOLTAGE OF A/F SENSOR)
Check the A/F sensor voltage output under the following conditions:
(2) Run the engine at approximately 2,500 rpm. Do not suddenly change the rpm.
(3) Raise the engine speed to 4,000 rpm and quickly release the accelerator pedal so that the throttle is fully closed.
Standard: Conditions (1) and (2). Voltage change of 3.3 V (0.66 V)* (between approximately 3.1 to 3.5 V) as shown in the Image.
Condition (3). A/F sensor voltage increases to 3.8 V (0.76 V)* or more when fuel is cut during engine deceleration as shown.
* Voltage when using the OBD II scan tool.
Diagnostic Toyota Solara a'05 with 3MZ-FE Engine: 4T1FA38P45U051510, 4T1CA38P75U059345, and Camry a 02 with 1MZ-FE Engine.
2. By version 3.6. with Toyota Enhanced Powertrain I can look (measure) in Menu "Live Data Graphs" Signal "Current of Air/fuel Ratio Sensor" in "mA".
Note: This Solara is fault-free, not broken, well works: 13.980 mileage, no DTC, good drivability and fuel consumption (16mpg), and like as new.
The strange Data... Take a look Voltage on A/F Ratio sensor.
4. Completely not correct data in menu "O2 Sensors".
Note. Toyota has use new "Planar" A/F Sensor. A second generation it Sensor was developed to meet more stringent emission regulations. This A/F Sensor reaches operating temperature faster that the previous (aka Cup Element) A/F sensor. This allows the ECM to go into closed loop vuel control faster when the engine is cold reducing cold start emission.
Like previous O2 and AF Sensors, the planar AFS has ambient air on one side of the ZrO2 and exhaust gases on the other side.
The planar AFS has the same detecting range and signal characteristics as the previous cup element. But heater element has higher resistance! This AFS is not interchangeable with the older, cup element AFS. Heater Resistance (at 68 degr.F)=1.8-3.4 Ohm. The heater is imbedded into aluminum oxide. When the heater is ON, the aluminum oxide conducts heat directly to the zirconium dioxide layer bring the AFS to operating temperature quickly.
The heater monitor continuously detects over current or under current condition and set DTC in one trip. The never planar AFS can be identified by its shorted body (13 mm).
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