DTC P2251:00 [L3 Turbo]

DTC P2251:00 [L3 Turbo]SM2444159

DTC P2251:00 [L3 Turbo]

id0102b7851300

DTC P2251:00	A/F sensor negative current control circuit open
DETECTION CONDITION	• The PCM monitors the A/F sensor terminal 1C voltage. If either of the following conditions are met, the PCM determines that the A/F sensor negative current control circuit is open. MONITORING CONDITIONS ― The A/F sensor element impedance specified or more. ― Circuit voltage oscillation or A/F sensor terminal 1C voltage is below the specified. ― The PCM detects the DTC P0134:00 while the pending code P2251:00 is stored. Diagnostic support note • This is a continuous monitor (A/F sensor, HO2S). • The MIL illuminates if the 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 the PCM detects the above malfunction conditions during the first drive cycle. • FREEZE FRAME DATA (Mode 2)/Snapshot data is available. • DTCs are stored in the PCM memory.
POSSIBLE CAUSE	• A/F sensor heater cannot be controlled • A/F sensor connector or terminals malfunction • PCM connector or terminals malfunction • Open circuit in wiring harness between A/F sensor terminal 1B and PCM terminal 2AC • A/F sensor malfunction • PCM malfunction

Diagnostic procedure

STEP	INSPECTION		ACTION
1	IDENTIFY TRIGGER DTC FOR FREEZE FRAME DATA (MODE 2) • Perform the Freeze Frame PID Data Access Procedure. (See ON-BOARD DIAGNOSTIC TEST [L3 Turbo].) • Is the DTC P2251:00 on FREEZE FRAME DATA (Mode 2)?	Yes	Go to the next step.
1		No	Go to the troubleshooting procedures for DTC on FREEZE FRAME DATA (Mode 2). (See DTC TABLE [L3 Turbo].)
2	VERIFY FREEZE FRAME DATA (MODE 2)/SNAPSHOT DATA AND DIAGNOSTIC MONITORING TEST RESULTS HAVE BEEN RECORDED • Have the snapshot data and DIAGNOSTIC MONITORING TEST RESULTS (A/F sensor, HO2S related) been recorded?	Yes	Go to the next step.
2		No	Record the FREEZE FRAME DATA (Mode 2)/snapshot data and DIAGNOSTIC MONITORING TEST RESULTS on repair order, then go to the next step.
3	VERIFY RELATED SERVICE 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.
3		No	Go to the next step.
4	VERIFY RELATED PENDING CODE AND STORED DTC • Turn the ignition switch off, then to the ON position (engine off). • Perform the DTC Reading Procedure and Pending Trouble Code Access Procedure. (See ON-BOARD DIAGNOSTIC TEST [L3 Turbo].) • Is the DTC P0031:00 or P0032:00 also present?	Yes	Go to the applicable DTC inspection. (See DTC P0031:00 [L3 Turbo].) (See DTC P0032:00 [L3 Turbo].)
4		No	Go to the next step.
5	INSPECT A/F SENSOR CONNECTOR CONDITION • Turn the ignition switch 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 connector and/or terminals, then go to Step 8.
5		No	Go to the next step.
6	INSPECT PCM CONNECTOR CONDITION • 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 connector and/or terminals, then go to Step 8.
6		No	Go to the next step.
7	INSPECT A/F SENSOR NEGATIVE CURRENT CONTROL CIRCUIT FOR OPEN CIRCUIT • A/F sensor and PCM connectors are disconnected. • Inspect for continuity between A/F sensor terminal 1B (wiring harness-side) and PCM terminal 2AC (wiring harness-side). • Is there continuity?	Yes	Replace the A/F sensor, then go to the next step. (See AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION [L3 Turbo].)
7		No	Repair or replace the wiring harness for a possible open circuit, then go to the next step.
8	VERIFY DTC TROUBLESHOOTING COMPLETED • Make sure to reconnect all disconnected connectors. • Clear the DTC from the PCM memory using the M-MDS. (See AFTER REPAIR PROCEDURE [L3 Turbo].) • Perform the KOEO or KOER self test. (See KOEO/KOER SELF TEST [L3 Turbo].) • Is the PENDING CODE for this DTC present?	Yes	Replace the PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION [L3 Turbo].)
8		No	Go to the next step.
9	VERIFY AFTER REPAIR PROCEDURE • Perform the “AFTER REPAIR PROCEDURE”. (See AFTER REPAIR PROCEDURE [L3 Turbo].) • Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [L3 Turbo].)
9		No	DTC troubleshooting completed.