AutoCodes – Saab – P1921 Saab

P1921 Saab Code - CAN Data Bus ECM

Quick Answer

P1921 Saab indicates CAN Data Bus ECM. Common causes include Faulty Engine Control Module (ECM), Engine Control Module (ECM) harness is open or shorted, Engine Control Module (ECM) circuit poor electrical connection. 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: P1921 Saab indicates CAN Data Bus ECM.
Common causes: Common causes include Faulty Engine Control Module (ECM), Engine Control Module (ECM) harness is open or shorted, Engine Control Module (ECM) circuit poor electrical connection.
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 2,143

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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Table of contents Created and updated by William Orellana on Sep 28, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1921 Saab Description

OBDII Code P1921 Saab - CAN Data Bus ECM - AutoCodes.com — P1921 Saab Code - CAN Data Bus ECM

What does this mean?

What are the Possible Causes of the DTC P1921 Saab?

Faulty Engine Control Module (ECM)
Engine Control Module (ECM) harness is open or shorted
Engine Control Module (ECM) circuit poor electrical connection

How to Fix the DTC P1921 Saab?

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 is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P1921 Saab 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 P1921 Saab Code

1. What are the common symptoms of OBDII code P1921 (Saab) related to the CAN Data Bus ECM?

The common symptoms include check engine light illumination, issues with the vehicle's drivability, and potential communication issues with various control modules.

2. What are the potential causes of OBDII code P1921 (Saab) indicating a problem with the CAN Data Bus ECM?

Possible causes include faulty wiring or connectors in the CAN bus system, a defective ECM (Engine Control Module), or issues with other control modules on the network.

3. How can I diagnose the OBDII code P1921 (Saab) related to the CAN Data Bus ECM?

Diagnosis typically involves using a diagnostic scanner to retrieve the trouble codes, checking the integrity of the CAN bus wiring, inspecting connectors for corrosion or damage, and testing the ECM and other control modules for proper communication.

4. Are there any repair tips for fixing OBDII code P1921 (Saab) associated with the CAN Data Bus ECM?

Repair tips include addressing any wiring or connector issues, ensuring proper grounding, checking for water ingress in connectors, and performing software updates if necessary.

5. Can OBDII code P1921 (Saab) related to the CAN Data Bus ECM be fixed by resetting the ECM?

While clearing the code may temporarily turn off the check engine light, it is essential to diagnose and address the underlying issue causing the fault code to prevent it from reoccurring.

6. What are the risks of ignoring OBDII code P1921 (Saab) linked to the CAN Data Bus ECM?

Ignoring the code can lead to poor vehicle performance, potential safety hazards due to communication errors between control modules, and may result in more severe issues over time.

7. Is it safe to continue driving with OBDII code P1921 (Saab) indicating a problem with the CAN Data Bus ECM?

It is not recommended to drive the vehicle with unresolved CAN bus communication issues, as it can affect various systems and potentially lead to more significant problems.

8. Can a DIY enthusiast repair OBDII code P1921 (Saab) related to the CAN Data Bus ECM?

While some basic troubleshooting steps can be performed by a DIY enthusiast, diagnosing and repairing CAN bus communication issues often require specialized tools and expertise, making professional assistance advisable.

9. How much does it typically cost to repair OBDII code P1921 (Saab) associated with the CAN Data Bus ECM?

The cost of repair can vary depending on the exact cause of the issue. It may range from a simple fix like repairing a wiring issue to more complex repairs involving control module replacement, with costs potentially ranging from a few hundred to over a thousand dollars.

10. Can extreme weather conditions contribute to triggering OBDII code P1921 (Saab) due to CAN Data Bus ECM issues?

Yes, extreme weather conditions such as excessive heat or moisture can impact the CAN bus system, potentially leading to communication errors and triggering fault codes like P1921.