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
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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
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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. (See KOEO/KOER SELF TEST [MZI-3.7].) • Is the PENDING CODE for this DTC present? | Yes | Repeat the inspection from Step 1. • If the malfunction recurs, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZI-3.7].) Go to the next step.
No | Go to the next step.
12 | VERIFY AFTER REPAIR PROCEDURE • Perform the “AFTER REPAIR PROCEDURE”. (See AFTER REPAIR PROCEDURE [MZI-3.7].) • Are any DTCs present? | Yes | Go to the applicable DTC inspection. (See DTC TABLE [MZI-3.7].)
No | Troubleshooting completed.