P2254

DTC P2254 OXYGEN SENSOR REFERENCE GROUND CIRCUIT/OPEN (FOR A/F SENSOR)(BANK 2 SENSOR 1)

CIRCUIT DESCRIPTION

DTC Detecting Condition:

HINT:
This DTC is recorded when A/F sensor is in a malfunction, although the caption is oxygen sensor. 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 A/F sensor has the characteristic that it provides output voltage* being 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 out of order, ECM is unable to perform the 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 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.

HINT:
- This DTC is recorded when A/F sensor is in a malfunction, although the caption is oxygen sensor.
- DTC P2237, P2238, P2239, P2251, P2252 and P2253 means malfunction related to bank 1 A/F sensor circuit.
- DTC P2240, P2241, P2242, P2254, P2255 and P2256 means malfunction related to bank 2 A/F sensor circuit.
- Bank 1 refers to the bank that includes cylinder No.1.
- Bank 2 refers to the bank that includes cylinder No.2.

Wiring Diagram:

Step 1 - 2:

Step 3:

INSPECTION PROCEDURE

HINT:
- If DTC P2237, P2238, P2239, P2251, P2252 or P2253 is displayed, check bank 1 sensor 1 circuit.
- If DTC P2240, P2241, P2242, P2254, P2255 or P2256 is displayed, check bank 2 sensor 1 circuit.
- 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.