DTC P2270

BHE010202200W05

DTC P2270

Rear HO2S signal stuck lean

DETECTION CONDITION

• The PCM monitors the input voltage from the rear HO2S when the following conditions are met. If the input voltage is more than 0.9 V for 40 s, the PCM determines that the rear HO2S signal remains lean.
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

• Leakage exhaust gas
• Rear HO2S malfunction
• Purge solenoid valve malfunction
• Fuel injector malfunction
• Leakage engine coolant
• PCM malfunction

Diagnostic procedure

STEP

INSPECTION

ACTION

1

VERIFY FREEZE FRAME DATA HAS BEEN RECORDED

• Has FREEZE FRAME DATA been recorded?
Yes
Go to the next step.
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.
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.)
No
Go to the next step.
4

IDENTIFY TRIGGER DTC FOR FREEZE FRAME DATA

• Is DTC P2270 on FREEZE FRAME DATA?
Yes
Go to the next step.
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 conditions (in PARK or NEUTRAL).
– More than 0.55 V when suddenly depress accelerator pedal (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.
No
Visually inspect for the the exhaust gas leakage between TWC and rear HO2S.
• If there is no leakage, replace the rear HO2S.
Then go to Step 10.
6

INSPECT FUEL LINE PRESSURE

• Perform the "FUEL LINE PRESSURE INSPECTION".
• Is there any malfunction?
Yes
Go to the next step.
No
Go to Step 10.
7

INSPECT PURGE SOLENOID VALVE

• Inspect the purge solenoid valve.
• Is there any malfunction?
Yes
Replace the purge solenoid valve, then go to Step 10.
No
Go to the next step.
8

INSPECT FUEL INJECTOR

• Inspect the fuel injector.
• Is there any malfunction?
Yes
Replace the fuel injector, then go to Step 10.
No
Go to the next step.
9

INSPECT ENGINE COOLANT PASSAGE FOR ENGINE COOLANT LEAKAGE

• Perform the "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.
No
Go to the next step.
10

VERIFY TROUBLESHOOTING OF DTC P2270 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.
• Is the PENDING CODE same as DTC present?
Yes
Replace the PCM, then go to the next step.
No
Go to the next step.
11

VERIFY AFTER REPAIR PROCEDURE

• Perform the "AFTER REPAIR PROCEDURE".
• Are any DTCs present?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE.)
No
DTC troubleshooting completed.