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Code C1121

Symptoms

• Steering wheel feels heavy or difficult to turn

• Power steering warning light on the dashboard

• Intermittent loss of power steering assistance

Common Causes

• Corrupted EEPROM data

• Faulty Power Steering Control Module

• Electrical issues such as poor connections or damaged wiring

Glossary

EEPROM: Electrically Erasable Programmable Read-Only Memory

OBD-II: On-Board Diagnostics, second generation

Related Codes

• C1120

• C1122

Laymans terms

The car's computer that helps with steering is having trouble remembering important information.

Explanation

The EEPROM (Electrically Erasable Programmable Read-Only Memory) in the Power Steering Control Module is not functioning correctly, which can affect the steering system.

Technical description

The C1121 code indicates a fault in the EEPROM of the Power Steering Control Module. This memory is crucial for storing data that the module uses to control the power steering system. A failure here can lead to improper steering assistance.

Diagnosis steps

• Check for other related codes and address them first.

• Inspect wiring and connectors to the Power Steering Control Module.

• Test the Power Steering Control Module for proper functionality.

Repair procedures

• Reprogram or replace the Power Steering Control Module.

• Repair or replace damaged wiring or connectors.

• Clear the code and test drive the vehicle to ensure the issue is resolved.

Tools required

• OBD-II scanner

• Multimeter

• Diagnostic software for module reprogramming

Estimated repair cost

$300 - $800

Difficulty level

Moderate

Commonly affected vehicles

• Ford Focus

• Nissan Altima

• Chevrolet Malibu

Preventive measures

• Regularly check and maintain the vehicle's electrical systems.

• Avoid exposing the vehicle's electronics to excessive moisture.

• Ensure all software updates are applied promptly.

Error code type

Control Module Issue

User experience recommendations

• If the steering feels heavy, avoid driving at high speeds.

• Get the vehicle checked by a professional mechanic as soon as possible.

Warranty information

Check if the vehicle's power steering system is covered under warranty, especially if the vehicle is relatively new.

Historical data

This code has been reported in various models, often related to electrical issues within the steering control system.

Urgency level

High – Steering issues can affect vehicle control and safety.

Legal and safety notice

Driving with impaired steering can lead to accidents. Address this issue promptly to ensure vehicle safety.

Testing conditions

• Vehicle at operating temperature

• Steering system engaged

Component location

The Power Steering Control Module is typically located near the steering column or within the engine compartment.

FAQs

Q: Can I drive with a C1121 code?
A: It's not recommended to drive with this code as it can affect steering performance and safety.

Q: How do I reset the C1121 code?
A: Fix the underlying issue first, then use an OBD-II scanner to clear the code.

Last updated: Jun 8, 2026 • Source: internal database
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