AutoCodes – Nissan – P1421 2008 Nissan Altima Sedan

P1421 2008 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 2008 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.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 5,275

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
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code P1421 2008 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 2008 Nissan Altima Sedan - Cold Start Control - AutoCodes.com — P1421 2008 Nissan Altima Sedan Code - Cold Start Control

What does this mean?

What are the Possible Causes of the DTC P1421 2008 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 2008 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 2008 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.

Need more information about the P1421 2008 Nissan Altima Sedan code?

Need more information on how to fix the P1421 2008 Nissan Altima Sedan code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P1421 2008 Nissan Altima Sedan code diagnosed by a professional: Find a repair shop in your area

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 2008 Nissan Altima Sedan Code

1. What does OBDII code P1421 on a 2008 Nissan Altima Sedan indicate?

- OBDII code P1421 in a 2008 Nissan Altima Sedan relates to the Cold Start Control system.

2. What are the common symptoms of OBDII code P1421 in a 2008 Nissan Altima Sedan?

- Common symptoms include rough idling, decreased fuel efficiency, and difficulty starting the engine when cold.

3. What are the possible causes of OBDII code P1421 in a 2008 Nissan Altima Sedan?

- Potential causes include a faulty cold start control valve, wiring issues, vacuum leaks, or a malfunctioning engine control module (ECM).

4. How can I diagnose the issue causing OBDII code P1421 in my 2008 Nissan Altima Sedan?

- Diagnostic steps may involve checking the cold start control valve, inspecting related wiring for damage, testing for vacuum leaks, and scanning the ECM for fault codes.

5. Can I continue driving my 2008 Nissan Altima Sedan with OBDII code P1421?

- It is not recommended to ignore OBDII code P1421, as it can lead to further engine performance issues if left unresolved.

6. How can I repair OBDII code P1421 in my 2008 Nissan Altima Sedan?

- Repair options may include replacing the cold start control valve, repairing wiring connections, fixing vacuum leaks, or reprogramming the ECM.

7. Is it possible to clear OBDII code P1421 in a 2008 Nissan Altima Sedan without fixing the underlying issue?

- Clearing the code without addressing the root cause may temporarily turn off the check engine light, but the problem will likely resurface.

8. Are there any maintenance tips to prevent OBDII code P1421 in a 2008 Nissan Altima Sedan?

- Regularly servicing the cold start control system, checking for vacuum leaks, and maintaining proper engine performance can help prevent this issue.

9. Can a DIY enthusiast fix OBDII code P1421 in a 2008 Nissan Altima Sedan?

- Depending on the cause, some DIY repairs like replacing the cold start control valve or checking for wiring issues may be possible for experienced individuals.

10. How long does it typically take to repair OBDII code P1421 in a 2008 Nissan Altima Sedan?

- The repair time can vary based on the specific cause and complexity of the issue, ranging from a quick fix to more extensive troubleshooting and part replacement.