P1421 – OBD-II DTC

OBD-II DTC P1421 – Port Air Circuit Malfunction/ (AIR) System Bank 2

DTC P1421 meaning

DTC P1421 refers to a malfunction in the Port Air Circuit of the Air Injection (AIR) System for Bank 2 of the engine. The AIR system is designed to reduce emissions by injecting air into the exhaust stream during cold starts, helping to burn off excess hydrocarbons. When the OBD-II system detects an issue with the air injection circuit for Bank 2, it triggers this diagnostic trouble code (DTC).

DTC P1421 symptoms

Common symptoms associated with DTC P1421 may include:

• Illuminated check engine light
• Increased emissions
• Rough engine idle
• Decreased fuel efficiency
• Possible failure during emissions testing

DTC P1421 causes

Several factors can lead to the triggering of DTC P1421, including:

• Faulty air injection pump
• Blocked or damaged air injection hoses
• Malfunctioning check valves
• Electrical issues such as short circuits or open circuits in the wiring
• Faulty engine control module (ECM)

DTC P1421 seriousness

The seriousness of DTC P1421 can vary. While it may not cause immediate drivability issues, it can lead to increased emissions and potential failure in emissions testing. Ignoring this code may result in further damage to the AIR system or other engine components over time.

How to diagnose DTC P1421

To diagnose DTC P1421, follow these steps:

1. Use an OBD-II scanner to confirm the presence of DTC P1421.
2. Inspect the air injection system components, including the pump, hoses, and check valves for visible damage or blockages.
3. Check the electrical connections and wiring for signs of wear, corrosion, or disconnection.
4. Test the air injection pump operation by applying direct power to it and observing if it runs.
5. Use a multimeter to check for proper voltage and ground at the pump connector.
6. Consult the vehicle’s service manual for specific testing procedures related to the AIR system.

How to fix DTC P1421 step-by-step instructions

To fix DTC P1421, follow these steps:

1. Repair or replace any damaged or blocked air injection hoses.
2. Replace a faulty air injection pump if it does not operate correctly.
3. Replace malfunctioning check valves to ensure proper airflow.
4. Repair any electrical issues found during diagnosis, such as frayed wires or poor connections.
5. Clear the DTC using an OBD-II scanner and test drive the vehicle to see if the code returns.

How to erase DTC P1421

To erase DTC P1421, follow these steps:

1. Connect an OBD-II scanner to the vehicle’s diagnostic port.
2. Turn on the ignition without starting the engine.
3. Navigate to the DTC menu on the scanner and select the option to erase or clear codes.
4. Confirm the action and wait for the scanner to indicate that the codes have been cleared.
5. Disconnect the scanner and start the engine to ensure the check engine light does not reappear.

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