AutoCodes – Nissan – P1421 2009 Nissan Altima Sedan

P1421 2009 Nissan Altima Sedan Code - Cold Start Control

Quick Answer

The Engine Control Module (ECM) controls ignition timing and engine idle speed when the engine is started with pre-warming up condition. Common causes include Lack of intake air volume (block air filter), Fuel injection system (Clogged fuel injector or bad fuel pump), Faulty Engine Control Module (ECM). Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P1421 2009 Nissan Altima Sedan indicates Cold Start Control.
Common causes: Common causes include Lack of intake air volume (block air filter), Fuel injection system (Clogged fuel injector or bad fuel pump), Faulty Engine Control Module (ECM).
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 6,991

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Oct 07, 2022

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P1421 2009 Nissan Altima Sedan Description

The Engine Control Module (ECM) controls ignition timing and engine idle speed when the engine is started with pre-warming up condition. This control promotes the activation of three-way catalyst by heating the catalyst and reduces emissions. The Diagnostic Trouble Code (DTC) will be set when the ECM does not control ignition timing and engine speed properly when the engine is started with prewarming up condition.

OBDII Code P1421 2009 Nissan Altima Sedan - Cold Start Control - AutoCodes.com — P1421 2009 Nissan Altima Sedan Code - Cold Start Control

What does this mean?

What are the Possible Causes of the DTC P1421 2009 Nissan Altima Sedan?

Lack of intake air volume (block air filter)
Fuel injection system (Clogged fuel injector or bad fuel pump)
Faulty Engine Control Module (ECM)

How to Fix the DTC P1421 2009 Nissan Altima Sedan?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

You can try to perform idle air volume relearn before doing anything else.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P1421 2009 Nissan Altima Sedan code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P1421 2009 Nissan Altima Sedan Code

1. What does OBDII code P1421 on a 2009 Nissan Altima Sedan indicate?

- OBDII code P1421 on a 2009 Nissan Altima Sedan relates to the Cold Start Control system, specifically pointing to an issue with the cold start air control.

2. What are common symptoms associated with OBDII code P1421 on a 2009 Nissan Altima Sedan?

- Common symptoms of P1421 may include difficulty starting the engine when cold, rough idling during cold starts, and potential stalling.

3. What are the possible causes of OBDII code P1421 on a 2009 Nissan Altima Sedan?

- The P1421 code can be triggered by a faulty cold start control valve, a vacuum leak in the intake system, or issues with the electrical circuit related to the cold start control.

4. How can I diagnose the cause of OBDII code P1421 on my 2009 Nissan Altima Sedan?

- Diagnosing P1421 involves checking the cold start control valve for proper operation, inspecting the intake system for vacuum leaks, and testing the electrical connections associated with the cold start control.

5. Can I still drive my 2009 Nissan Altima Sedan with the OBDII code P1421 present?

- It is not recommended to drive your vehicle extensively with the P1421 code active, as it can lead to potential performance issues, reduced fuel efficiency, and possible engine stalling.

6. How serious is the OBDII code P1421 on a 2009 Nissan Altima Sedan?

- While the P1421 code may not result in immediate engine failure, it is important to address the underlying issue promptly to prevent further damage and ensure optimal vehicle performance.

7. Are there any DIY repair tips for fixing OBDII code P1421 on a 2009 Nissan Altima Sedan?

- DIY repair tips for P1421 include checking and cleaning the cold start control valve, inspecting and repairing any vacuum leaks, and ensuring all electrical connections are secure.

8. Can a malfunctioning cold start control valve trigger the OBDII code P1421 on a 2009 Nissan Altima Sedan?

- Yes, a malfunctioning cold start control valve is a common culprit for triggering the P1421 code on a 2009 Nissan Altima Sedan due to its vital role in the cold start process.

9. How much does it typically cost to repair OBDII code P1421 on a 2009 Nissan Altima Sedan?

- The cost of repairing P1421 can vary depending on the exact cause of the issue, but it may range from $150 to $400, including parts and labor.

10. Is it necessary to reset the OBDII code P1421 after repairing the issue on a 2009 Nissan Altima Sedan?

- Yes, it is recommended to reset the OBDII code P1421 after resolving the underlying problem to clear the error code and ensure proper functioning of the vehicle's diagnostic system.