DTC P2271:00, P2273:00 [MZI-3.7]

id0102d2319800

DTC P2271:00

DTC P2273:00

P2271:00: HO2S (RH) signal stuck rich

P2273:00: HO2S (LH) signal stuck rich
DETECTION CONDITION
•  The downstream HO2S is forced rich and monitored by the PCM. The test fails if the PCM does not detect the output of the HO2S in a calibrated amount of time.
POSSIBLE CAUSE
Electrical System:
•  P2271:00: Short to ground between HO2S (RH) terminal B and PCM terminal 3Z
•  P2273:00: Short to ground between HO2S (LH) terminal B and PCM terminal 3AB
•  HO2S signal circuit short to other HO2S harness
•  P2271:00: Short to power supply between HO2S (RH) terminal B and PCM terminal 3Z
•  P2273:00: Short to power supply between HO2S (LH) terminal B and PCM terminal 3AB
•  HO2S malfunction
•  PCM malfunction
Intake Air System:
•  Air leaks
•  Vacuum leaks
•  PCV system malfunction
•  Incorrectly seated engine oil dipstick, tube or oil filler cap
Base Engine:
•  Exhaust leaks (flange, gaskets)

Diagnostic procedure

STEP

INSPECTION

ACTION
1
IDENTIFY TRIGGER DTC FOR FREEZE FRAME DATA
•  Is DTC P2271:00 or P2273:00 on FREEZE FRAME DATA?
Yes
Go to the next step.
No
Go to the troubleshooting for the DTC on the FREEZE FRAME DATA.
(See DTC TABLE [MZI-3.7].)
2
VERIFY FREEZE FRAME DATA HAS BEEN RECORDED
•  Has FREEZE FRAME DATA been recorded?
Yes
Go to the next step.
No
Record FREEZE FRAME DATA on the 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.
No
Perform the PCM reprogramming procedure.
(See PCM CONFIGURATION [MZI-3.7].)
Go to the next step.
4
VERIFY RELATED PENDING CODE OR STORED DTCs
•  Turn the ignition switch off then to the ON position (Engine off).
•  Verify the related PENDING CODE or stored DTCs using the M-MDS.
Yes
Go to the appropriate DTC troubleshooting.
(See DTC TABLE [MZI-3.7].)
No
Go to the next step.
5
INSPECT FOR KOER DTCS
•  Turn the ignition switch to the ON position (Engine off).
•  Clear the DTCs.
•  Start the engine.
•  Run the engine at approximately 2,000 RPM. Maintain the engine speed for 3 min.
•  Retrieve the continuous memory DTCs.
•  Is DTC P2271:00 or P2273:00 present?
Yes
Go to the next step.
No
Unable to duplicate or identify the concern at this time.
6
CHECK IF HO2S SIGNAL LEVEL IS TOO HIGH
Note
•  Fuel calculations can be affected by unmetered air leaks.
•  Turn the ignition switch off.
•  Carefully inspect the following areas for potential air leaks:
―  Hoses connecting to the MAF sensor assembly
―  Hoses connecting to the throttle body
―  Intake manifold gasket leaks
―  PCV system
―  Vacuum lines are disconnected
―  Improperly seated engine oil dipstick, tube or oil fill cap
―  Exhaust leaks at flanges and gaskets
•  Is a concern present?
Yes
Repair or replace malfunctioning part, then go to Step 11.
No
Go to the next step.
7
INSPECT FOR SHORT CIRCUIT BETWEEN CIRCUITS IN HO2S WIRING HARNESS
•  Turn the ignition switch off.
•  Disconnect the PCM and suspect HO2S connectors.
•  Measure the resistance between following PCM wiring harness-side connector terminal and battery negative terminal.
For DTC P2271:00:
―  Terminal 3Z
For DTC P2273:00:
―  Terminal 3AB
•  Are the resistances greater than 10 kilohms?
Yes
Go to the next step.
No
Repair for a short circuit, then go to Step 11.
8
INSPECT FOR SHORT CIRCUIT BETWEEN CIRCUITS IN HO2S WIRING HARNESS
•  PCM and suspect HO2S connectors are disconnected.
•  Measure the resistance between the following on the PCM wiring harness-side connector.
For DTC P2271:00:
―  Terminal 3Z and terminal 2G
―  Terminal 3Z and terminal 3N
For DTC P2273:00:
―  Terminal 3AB and terminal 2G
―  Terminal 3AB and terminal 3AM
•  Are the resistances greater than 10 kilohms?
Yes
Go to the next step.
No
Repair for a short circuit, then go to Step 11
9
INSPECT HO2S CIRCUIT FOR SHORT CIRCUIT POWER SUPPLY IN WIRING HARNESS
•  Disconnect the PCM and suspect HO2S connectors.
•  Measure the resistance at the following terminals (wiring harness-side).
For DTC P2271:00:
―  PCM terminal 3Z—HO2S (RH) terminal C
For DTC P2273:00:
―  PCM terminal 3AB—HO2S (LH) terminal C
•  Are the resistances greater than 10 kilohms?
Yes
Go to the next step.
No
Repair for a short circuit, then go to Step 11.
10
CHECK HO2S CIRCUIT VOLTAGE FOR SHORT CIRCUIT TO POWER SUPPLY IN HO2S
•  Turn the ignition switch off.
•  Reconnect PCM connector.
•  Disconnect the suspect HO2S connector.
•  Connect a 5A fuse jumper wire between terminal B and C on the suspect HO2S wiring harness-side connector.
•  Start the engine and run it at idle.
•  Access and monitor the following PCM the HO2S Signal PID using the M-MDS.
For DTC P2271:00:
―  O2S12
For DTC P2273:00:
―  O2S22
•  Is the voltage greater than 1.5 V?
Yes
Replace the suspect HO2S.
(See HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION [MZI-3.7].)
Then go to the next step.
No
Go to the next step.
(The system is operating normally at this time. The concern may have been caused by a loose or corroded connector.)
11
VERIFY TROUBLESHOOTING OF DTC P2271:00, P2273:00 HAS BEEN COMPLETED
•  Verify that all disconnected connectors are reconnected.
•  Turn the ignition switch to the ON position (Engine off).
•  Clear the DTC from the PCM memory using the M-MDS.
•  Perform no load racing at the engine speed of 2,500—3,500 rpm for 60s or more, then idle the engine for 60s or more.
•  Perform the KOER self-test.
•  Is the PENDING CODE for this DTC present?
Yes
Repeat the inspection from Step 1.
•  If the malfunction recurs, replace the PCM.
Go to the next step.
No
Go to the next step.
12
VERIFY AFTER REPAIR PROCEDURE
•  Perform the “AFTER REPAIR PROCEDURE”.
•  Are any DTCs present?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE [MZI-3.7].)
No
Troubleshooting completed.