AutoCodes – Generic – C1551

C1551 Code - Power Supply Voltage Malfunction

Quick Answer

The Power Steering ECU monitors itself for proper operation. Common causes include Power Steering ECU Fuse, Faulty Power Steering ECU, Power Steering ECU harness is open or shorted. 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: C1551 indicates Power Supply Voltage Malfunction.
Common causes: Common causes include Power Steering ECU Fuse, Faulty Power Steering ECU, Power Steering ECU harness is open or shorted.
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 2,351

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Feb 22, 2023

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code C1551 Description

The Power Steering ECU monitors itself for proper operation. The Power Steering ECU sets the OBDII code when it detects an internal malfunction. The Power Steering ECU distinguishes the ignition switch status as ON or OFF through the IG power source circuit. The Diagnostic Trouble Code (DTC) will be set when an IG power source circuit malfunctions inside ECU.

OBDII Code C1551 - Power Supply Voltage Malfunction - AutoCodes.com — C1551 Code - Power Supply Voltage Malfunction

What does this mean?

What are the Possible Causes of the DTC C1551?

Power Steering ECU Fuse
Faulty Power Steering ECU
Power Steering ECU harness is open or shorted
Power Steering ECU circuit poor electrical connection

How to Fix the DTC C1551?

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 C1551 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 C1551 code?

Need more information on how to fix the C1551 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the C1551 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

C1551 Lexus — Power Supply Voltage Malfunction
C1551 Scion — Power Supply Voltage Malfunction
C1551 Toyota — Power Supply Voltage Malfunction

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 C1551 Code

1. What are common symptoms of OBDII code C1551 (Power Supply Voltage Malfunction)?

- Common symptoms include difficulty starting the vehicle, intermittent loss of power, and illuminated warning lights on the dashboard.

2. What are the possible causes of OBDII code C1551?

- The code C1551 can be triggered by issues such as a faulty power supply module, damaged wiring harness, or a failing voltage regulator.

3. How can I diagnose the cause of OBDII code C1551?

- A thorough inspection of the power supply system, including checking the battery, alternator, and related components, is recommended to diagnose the cause of code C1551.

4. Can a DIY enthusiast repair OBDII code C1551?

- Repairing code C1551 may require advanced diagnostic tools and technical knowledge. It is advisable to consult a professional mechanic for accurate diagnosis and repair.

5. Are there any safety precautions to consider when dealing with OBDII code C1551?

- When troubleshooting code C1551, it is important to disconnect the battery and follow proper safety procedures to avoid electrical hazards.

6. How does OBDII code C1551 affect vehicle performance?

- OBDII code C1551 can cause erratic engine performance, reduced fuel efficiency, and potential stalling or loss of power while driving.

7. Can OBDII code C1551 be cleared/reset without fixing the underlying issue?

- Clearing the OBDII code without addressing the root cause may temporarily turn off the warning light, but the issue will likely recur until the problem is fixed.

8. Is it safe to continue driving with OBDII code C1551 present?

- It is not recommended to drive with OBDII code C1551 active, as it can lead to further damage to the vehicle and potentially compromise safety.

9. How much does it typically cost to repair OBDII code C1551?

- The cost of repairing OBDII code C1551 can vary depending on the specific cause of the issue, but it may involve expenses for parts and labor.

10. Can extreme weather conditions contribute to triggering OBDII code C1551?

- Yes, extreme weather conditions such as extreme heat or cold can sometimes exacerbate existing issues related to power supply voltage, leading to the triggering of code C1551.