Troubleshooting
DTC P2197 Oxygen (A/F) Sensor Signal Stuck Lean (Bank 2 Sensor 1)CIRCUIT DESCRIPTION
DTC Detecting Condition:
To obtain a high purification rate for the CO, HC and NOx components of the exhaust gas, a three-way catalytic converter is used. But 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 A/F sensor has the characteristic that provides output voltage* approximately proportional 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.
By the A/F sensor output, the ECM can determine the deviation amount from the stoichiometric air-fuel ratio and control the proper injection time immediately. If the A/F sensor is malfunctioning, ECM is unable to perform accurate air-fuel ratio control.
The A/F 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 temp. of the exhaust gas is low), current flows to the heater to heat the sensor for accurate oxygen concentration detection.
*: The voltage value changes at the inside of the ECM only.
HINT:
- After confirming DTC P2195, P2197, P2198, P2237 or P2240, use the OBD II scan tool or hand-held tester to confirm the voltage output of the A/F sensor (AFS B1S1/02S B1 S1) from "CURRENT DATA".
- The A/F sensor's output voltage and the short-term fuel value can be read using the OBD II scan tool or hand-held tester.
- The ECM controls the voltage of AFR/AFL(+) and AFR/AFL(-) terminals of ECM to the fixed voltage. Therefore, it is impossible to confirm the A/F 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 A/F sensor output voltage which is displayed on the hand-held tester.
Wiring Diagram:
CONFIRMATION DRIVING PATTERN
1. Connect the hand-held tester to the DLC3.
2. Switch the hand-held tester from normal mode to check mode.
3. Start the engine and warm it up for 2 minutes or more with all accessory switches OFF.
4. Drive the vehicle at 60 - 120 km/h (38 - 75 mph) and engine speed at 1,600 - 3,200 rpm for 3 - 5 minutes
HINT: If a malfunction exists, the MIL will light up during step 4..
NOTE: If the conditions in this test are not strictly followed, detection of the malfunction will impossible.
If you do not have a hand-held tester, turn the ignition switch OFF after performing steps (3) and (4), then perform steps (3) and (4) again.
Step 1 - 2:
Step 3:
Step 3 (continued) - 4:
Step 5 - 9:
Step 10 - 14:
Step 15 - 19:
INSPECTION PROCEDURE
HINT:
- If DTC P2195, P2196 or P2237 is displayed, check Bank 1 Sensor 1 circuit.
- If DTC P2197, P2198 or P2240 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.
- Sensor 1 refers to the sensor closest to the engine body.
- Read freeze frame data using hand-held tester or OBD II scan tool, as freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, it is useful to determine 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, 1 trip detection logic is possible instead of 2 trip detection logic and sensitivity 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.