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DTC P2251 [L8, LF, L3]

id0102a1813400

DTC P2251 | A/F sensor negative current control circuit open
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DETECTION CONDITION | • The PCM monitors A/F sensor negative current control circuit voltage. If the voltage is not changed against the PCM control value while the engine running, the PCM determines that the A/F sensor negative current control circuit is open. Diagnostic support note • This is a continuous monitor. (A/F sensor , HO2S) • MIL illuminates if PCM detects the above malfunctioning condition in two consecutive drive cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM. • PENDING CODE is available if PCM detects the above malfunction conditions during first drive cycle. • FREEZE FRAME DATA is available. • DTC is stored in the PCM memory
POSSIBLE CAUSE | • A/F sensor malfunction • Connector or terminal malfunction • Open circuit between PCM terminal 2AC and A/F sensor terminal 1B • A/F sensor heater can not be controlled • PCM malfunction

Diagnostic procedure

STEP | INSPECTION | ACTION
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1 | VERIFY FREEZE FRAME DATA AND DIAGNOSTIC MONITORING TEST RESULTS HAS BEEN RECORDED • Has FREEZE FRAME DATA been recorded? | Yes | Go to the next step.
No | Record the FREEZE FRAME on the repair order, then go to the next step.
2 | VERIFY RELATED REPAIR INFORMATION AVAILABILITY • Verify related Service Information availability. • Is any related Service Information available? | Yes | Perform repair or diagnosis according to the available Service information. If the vehicle is not repaired, go to the next step.
No | Go to the next step.
3 | VERIFY RELATED PENDING CODE OR STORED DTC • Turn the ignition switch off, then ON position (Engine off). • Verify the related PENDING CODE or stored DTCs using the WDS or equivalent. • Is the DTC P0030, P0031 or P0032 also present? | Yes | Go to appropriate DTC troubleshooting procedure. (See DTC TABLE [L8, LF, L3].)
No | Go to the next step.
4 | IDENTIFY TRIGGER DTC FOR FREEZE FRAME DATA • Is the DTC P2251 on FREEZE FRAME DATA? | Yes | Go to the next step.
No | Go to troubleshooting for DTC on FREEZE FRAME DATA. (See DTC TABLE [L8, LF, L3].)
5 | INSPECT A/F SENSOR CONNECTOR FOR POOR CONNECTION • Turn the ignition switch to off. • Disconnect the A/F sensor connector. • Inspect for poor connection (such as damaged/pulled-out pins, and corrosion). • Is there any malfunction? | Yes | Repair or replace the terminal, then go to Step 8.
No | Go to the next step.
6 | INSPECT PCM CONNECTOR FOR POOR CONNECTION • Turn the ignition switch to off. • Disconnect the PCM connector. • Inspect for poor connection (such as damaged/pulled-out pins, and corrosion). • Is there any malfunction? | Yes | Repair or replace the terminal, then go to Step 8.
No | Go to the next step.
7 | INSPECT A/F SENSOR NEGATIVE CURRENT CONTROL CIRCUIT FOR OPEN CIRCUIT • A/F sensor and PCM connectors disconnected. • Verify the continuity between PCM terminal 2AC and 1B at wiring harness-side connectors. • Is there continuity? | Yes | Replace the A/F sensor, then go to the next step.
No | Repair or replace for an open circuit, then go to the next step.
8 | VERIFY TROUBLESHOOTING OF DTC P2251 COMPLETED • Make sure to reconnect all disconnected connectors • Clear the DTC from the PCM memory using the WDS or equivalent. • Perform the KOEO or KOER self-test. (See KOEO/KOER SELF TEST [L8, LF, L3].) • Is the DTC P2251 present? | Yes | Replace the PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION [L8, LF, L3].)
No | Go to the next step.
9 | VERIFY AFTER REPAIR PROCEDURE • Perform the "After Repair Procedure". (See AFTER REPAIR PROCEDURE [L8, LF, L3].) • Are any DTCs present? | Yes | Go to the applicable DTC inspection. (See DTC TABLE [L8, LF, L3].)
No | Troubleshooting completed.