DTC P2271


DTC P2271	Rear HO2S signal stuck rich
DETECTION CONDITION	• The PCM monitors the input voltage from the rear HO2S when the following conditions are met. If the input voltage is less than 0.4 V for 40 s, the PCM determines that the rear HO2S signal remains rich. MONITORING CONDITION – ECT: more than 70 °C {158 °F} – Engine speed: more than 1,500 rpm – MAF amount: more than 10 g/s {1.32 lb/min} – Short term fuel trim: -20-20 % – Long term fuel trim: -15-15 % – Target A/F feedback system status: feedback control Diagnostic support note • This is an intermittent monitor (HO2S). • The MIL illuminates if the PCM detects the above malfunction 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 condition during the first drive cycle. • FREEZE FRAME DATA is available. • The DTC is stored in the PCM memory.
POSSIBLE CAUSE	• Front HO2S malfunction • Rear HO2S malfunction • Front HO2S heater malfunction • Rear HO2S heater malfunction • Fuel pump control malfunction • Fuel pressure malfunction • Fuel injector malfunction • Leakage exhaust gas • Purge solenoid valve malfunction • Purge solenoid valve hoses improper connection • AIR system malfunction • Insufficient compression – Engine oil malfunction – Rised oil pressure – Metering oil pump malfunction – Metering oil pump control malfunction – Engine malfunction • PCM malfunction


STEP	INSPECTION		ACTION
1	VERIFY FREEZE FRAME DATA HAS BEEN RECORDED • Has FREEZE FRAME DATA been recorded?	Yes	Go to the next step.
1		No	Record the FREEZE FRAME DATA on the repair order, then go to the next step.
2	VERIFY RELATED REPAIR INFORMATION AVAILABILITY • Verify related service repair information availability. • Is any related repair information available?	Yes	Perform repair or diagnosis according to the available repair information. • If the vehicle is not repaired, go to the next step.
2		No	Go to the next step.
3	VERIFY RELATED PENDING CODE OR STORED DTC • Turn the ignition switch off, then to the ON position (Engine off). • Verify the related PENDING CODE or stored DTCs. • Are other DTCs present?	Yes	Go to the appropriate DTC inspection. (See DTC TABLE.)
3		No	Go to the next step.
4	IDENTIFY TRIGGER DTC FOR FREEZE FRAME DATA • Is DTC P2271 on FREEZE FRAME DATA?	Yes	Go to the next step.
4		No	Go to the FREEZE FRAME DATA DTC inspection. (See DTC TABLE.)
5	VERIFY CURRENT INPUT SIGNAL STATUS OF REAR HO2S • Connect the WDS or equivalent to the DLC-2. • Start the engine and warm it up completely. • Access the O2S12 PID. • Read the O2S12 PID under following accelerator pedal condition (in PARK or NEUTRAL). – More than 0.55 V when accelerator pedal is suddenly depressed (rich condition). – Less than 0.55 V just after release of accelerator pedal (lean condition) • Is the PID normal?	Yes	Go to the next step.
5		No	Visually inspect for the the gas leakage between TWC and rear HO2S. • If there is no leakage, replace the rear HO2S. (See REAR HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION.) Then go to Step 21.
6	INSPECT PURGE SOLENOID VALVE • Inspect the purge solenoid valve. (See PURGE SOLENOID VALVE INSPECTION.) • Is there any malfunction?	Yes	Replace the purge solenoid valve, then go to Step 21. (See INTAKE-AIR SYSTEM HOSE ROUTING DIAGRAM.)
6		No	Go to the next step.
7	INSPECT AIR SYSTEM OPERATION • Perform the "AIR System Inspection". (See Secondary Air Injection (AIR) System Inspection.) • Does AIR system operate properly?	Yes	Go to the next step.
7		No	Repair or replace malfunctioning part according to the inspection results. Then go to Step 21
8	INSPECT FUEL LINE PRESSURE • Perform the "FUEL LINE PRESSURE INSPECTION". (See FUEL LINE PRESSURE INSPECTION.) • Is there any malfunction?	Yes	Go to the next step.
8		No	Go to Step 10.
9	INSPECT FUEL SYSTEM FOR FUEL LEAKAGE • Visually inspect fuel leakage in the fuel system. • Is there fuel leakage?	Yes	Repair or replace the malfunctioning part, then go to Step 21.
9		No	Replace the fuel pump unit, then go to Step 21. (See FUEL PUMP UNIT REMOVAL/INSTALLATION.)
10	INSPECT IGNITION COIL OPERATION AND HIGH-TENSION LEAD WITH TIMING LIGHT • Inspect the blinking condition on each high-tension lead using timing light at idle. • Do all the high-tension leads show blinking condition?	Yes	Go to Step 14.
10		No	Go to the next step.
11	INSPECT HIGH-TENSION LEAD OF NO BLINKING HIGH-TENSION LEAD • Inspect the high-tension leads. (See HIGH-TENSION LEAD INSPECTION.) • Is there any malfunction?	Yes	Replace the malfunctioning high-tension lead, then go to Step 24. (See HIGH-TENSION LEAD REMOVAL/INSTALLATION.)
11		No	Go to the next step.
12	INSPECT IGNITION COIL POWER CIRCUIT FOR OPEN CIRCUIT OR SHORT TO GND • Turn the ignition switch to the ON position (Engine off). • Measure the voltage between ignition coil terminal C (wiring harness-side) and body GND. • Is the voltage B+?	Yes	Go to the next step.
12		No	Repair or replace the wiring harness for a possible open circuit or short to GND, then go to Step 21.
13	INSPECT IGNITION COIL • Inspect the ignition coil. (See IGNITION COIL INSPECTION.) • Is there any malfunction?	Yes	Replace the ignition coil, then go to Step 21. (See IGNITION COIL REMOVAL/INSTALLATION.)
13		No	Go to the next step.
14	INSPECT ENGINE COMPRESSION • Inspect the engine compression. (See COMPRESSION INSPECTION.) • Is there any malfunction?	Yes	Go to the next step.
14		No	Go to Step 19.
15	INSPECT METERING OIL PUMP • Inspect the metering oil pump. (See METERING OIL PUMP INSPECTION.) • Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results. Overhaul or replace the engine. Then go to Step 21.
15		No	Go to the next step.
16	INSPECT ENGINE OIL CONDITION • Inspect the engine oil condition. • Is the engine oil condition normal?	Yes	Go to the next step.
16		No	Replace the engine oil. Inspect the ECT sensor and related harnesses. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION.) Overhaul or replace the engine. Then go to Step 21.
17	INSPECT OIL PRESSURE • Inspect the oil pressure. (See OIL PRESSURE INSPECTION.) • Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results. Overhaul or replace the engine. Then go to Step 21.
17		No	Go to the next step.
18	INSPECT OIL PASSAGE • Inspect the oil pipe between metering oil pump and metering oil nozzle. • Is there any malfunction?	Yes	Inspect and repair for leakage and/or clogged in oil passage at engine. Overhaul or replace the engine. Then go to Step 21.
18		No	Overhaul or replace the engine. Then go to Step 21.
19	INSPECT FUEL INJECTOR • Inspect the fuel injector. (See FUEL INJECTOR INSPECTION.) • Is there any malfunction?	Yes	Replace the fuel injector, then go to Step 21. (See FUEL INJECTOR REMOVAL/INSTALLATION.)
19		No	Go to the next step.
20	INSPECT ENGINE COOLANT PASSAGE FOR ENGINE COOLANT LEAKAGE • Perform the "ENGINE COOLANT LEAKAGE INSPECTION". (See ENGINE COOLANT LEAKAGE INSPECTION.) • Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results. Then go to the next step.
20		No	Go to the next step.
21	VERIFY TROUBLESHOOTING OF DTC P2271 COMPLETED • Make sure to reconnect all disconnected connectors. • Clear the DTC from the PCM memory using the WDS or equivalent. • Perform the DRIVE MODE 1 and 3. (See OBD DRIVE MODE.) • Is the PENDING CODE same as DTC present?	Yes	Replace the PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION.)
21		No	Go to the next step.
22	VERIFY AFTER REPAIR PROCEDURE • Perform the "AFTER REPAIR PROCEDURE". (See AFTER REPAIR PROCEDURE.) • Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE.)
22		No	DTC troubleshooting completed.