Troubleshooting
DTC P2196 OXYGEN (A/F) SENSOR SIGNAL STUCK RICH (BANK 1 SENSOR 1)HINT: Although each DTC title says "oxygen sensor", these DTCs are related to the A/F sensor.
CIRCUIT DESCRIPTION
DTC Detecting Condition:
The air-fuel ratio (A/F) sensor provides output voltage* which is almost 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 the air-fuel ratio.
The A/F sensor is equipped with a heater which heats the zirconia element. The heater is also controlled by the ECM. When the intake air volume is low (the temperature of the exhaust gas is low), current flows to the heater to heat the sensor to facilitate detection of accurate oxygen concentration. The A/F sensor is a planar type. Compared to a conventional type, the sensor and heater portions are narrower. Because the heat of the heater is conducted through the alumina to zirconia (of the sensor portion), sensor activation is accelerated.
To obtain a high purification rate of carbon monoxides (CO), hydrocarbons (HC) and nitrogen oxides (NOx) components of the exhaust gas, a three-way catalytic converter is used. The converter is most efficient when the air-fuel ratio is maintained near the stoichiometric air-fuel ratio.
*: The voltage value changes inside the ECM only.
HINT:
- Sensor 1 refers to the sensor closest to the engine assembly.
- After confirming DTC P2195 and P2196, use the OBD II scan tool or the hand-held tester to confirm voltage output of A/F sensor (AFS B1 S1) from the "DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY."
- The A/F sensor's output voltage and the short-term fuel trim value can be read using the OBD II scan tool or the hand-held tester.
- The ECM controls the voltage of the A1A+, and A1A- terminals of the ECM to a fixed voltage. Therefore, it is impossible to confirm the A/F sensor output voltage without the OBD II scan tool or the hand-held tester.
- The OBD II scan tool (excluding hand-held tester) displays the one fifth of the A/F sensor output voltage which is displayed on the hand-held tester.
MONITOR DESCRIPTION
Monitor Strategy:
Typical Enabling Conditions:
Typical Malfunction Thresholds:
Under the air-fuel ratio feedback control, if the voltage output of the A/F sensor indicates RICH or LEAN for a certain period of time or more, the ECM concludes that there is a fault in the A/F sensor system. The ECM will turn on the MIL and a DTC is set.
If the A/F sensor voltage output is less than 2.8 V (indicates very RICH) 10 seconds even though voltage output of the heated oxygen sensor output voltage is less than 0.85 V, the ECM sets DTC P2196 Also, 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 (indicates very LEAN) for 10 seconds, DTC P2195 or is set.
Wiring Diagram:
CONFIRMATION DRIVING PATTERN
Confirmation Driving Patern:
a. Connect the hand-held tester to the DLC3.
b. Switch the ECM from normal mode to check mode using the hand-held tester.
c. Put the engine in inspection mode.
d. Start the engine and warm it up with all the accessory switches OFF.
e. Deactivate the inspection mode and drive the vehicle at 44 to 75 mph (70 to 120 km/h) for 5 to 10 minutes (the engine must be run during monitoring).
HINT: If malfunction exists, the MIL will be illuminated during step (d).
NOTE:
- If the conditions in this test are not strictly followed, no malfunction will be detected. If you do not have the hand-held tester, turn the power switch OFF after performing steps (d) and (e), then perform steps (d) and (e) again.
- Do not drive the vehicle without deactivating inspection mode, otherwise damaging the transaxle may result.
Step 1 - 2:
Step 2 (Continued):
Step 2 (Continued) - 4:
Step 5:
Step 6 - 10:
Step 11 - 14:
Step 15 - 18:
INSPECTION PROCEDURE
HINT: Malfunctioning areas can be found by performing the ACTIVE TEST / A/F CONTROL operation. The A/F CONTROL operation can determine if the A/F sensor, heated oxygen sensor or other potential trouble area are malfunctioning or not.
a. Perform the ACTIVE TEST A/F CONTROL operation.
HINT: The A/F CONTROL operation lowers the injection volume 12.5% or increases the injection volume 25%.
1. Connect the hand-held tester to the DLC3 on the vehicle.
2. Turn the power switch ON (IG).
3. Put the engine in inspection mode.
4. Warm up the engine by running the engine at 2,500 rpm with the accelerator pedal depressed more than 60 % for approximately 90 seconds.
5. Select the item: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/F CONTROL.
6. Perform the A/F CONTROL operation with the engine in an idle condition (press the right or left button).
Result:
A/F sensor reacts in accordance with increase and decrease of injection volume:
+25 % -> rich output: Less than 3.0 V
-12.5 % -> lean output: More than 3.35 V
Heated oxygen sensor reacts in accordance with increase and decrease of injection volume:
+25 % -> rich output: More than 0.55 V
-12.5 % -> lean output: Less than 0.4 V
NOTE: The A/F sensor output has a few seconds of delay and the heated oxygen sensor output has about 20 seconds of delay at maximum.
The A/F CONTROL procedure enables the technician to check and graph the voltage output of both A/F sensor and heated oxygen sensor.
To display the graph, enter ACTIVE TEST / A/F CONTROL / USER DATA, select "AFS B1S1 and O2S B1S2" by pressing the "YES" button followed by the "ENTER" button and then the "F4" button.
- Read freeze frame data using the hand-held tester or the OBD II scan tool. Freeze frame data records the engine condition when malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.
- A high A/F sensor voltage could be caused by a RICH air-fuel mixture. Check the conditions that would cause the engine to run with the RICH air-fuel mixture.
- A low A/F sensor voltage could be caused by a LEAN air-fuel mixture. Check the conditions that would cause the engine to run with the LEAN air-fuel mixture.
CHECK FOR INTERMITTENT PROBLEMS
HINT: Inspect the vehicle's ECM using check mode. Intermittent problems are easier to detect when the ECM is in test mode with a hand-held tester. In check mode, the ECM uses 1 trip detection logic, which has a higher sensitivity to malfunctions than normal mode (default) using 2 trip detection logic.
a. Clear the DTCs.
b. Switch the hand-held tester from normal mode to check mode.
c. Perform a simulation test.
d. Check the connector(s) and terminal(s).
e. Wiggle the harness(s) and connector(s).