A weak or failing 12-volt battery, causing low voltage to the active steering module.; Corroded, loose, or damaged wiring or connectors at the active steering module or its power/ground points.; A blown fuse or faulty relay that supplies power to the active steering module.; A faulty active steering module, though this is less common than wiring or power issues.; Communication network faults, such as a shorted or open data bus wire, affecting module messages.; Poor ground connection for the active steering module or the network it uses.; Aftermarket accessories or improper electrical repairs that interfere with the communication bus.

DTC codes / C07xx · Brakes, steering and suspension / C0700

C0700Active Steering Module Communication

Q: What does code C0700 mean?

Active Steering Module Communication. C0700 indicates that the active steering module, which controls the power steering assist, has lost communication with the rest of the vehicle's network. The computer detected a failure to receive expected messages from the module, often due to a wiring or power issue rather than a failed module itself.

C0700 indicates that the active steering module, which controls the power steering assist, has lost communication with the rest of the vehicle's network. The computer detected a failure to receive expected messages from the module, often due to a wiring or power issue rather than a failed module itself.

SystemChassis

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaBrakes, steering and suspension

Symptoms you may notice

The power steering warning light or a stability control warning light illuminates on the dashboard.
The steering may feel heavier or require more effort, especially at low speeds.
The steering assist may become intermittent or suddenly reduce while driving.
Often no symptoms besides the warning light, with steering feel unchanged.
Other dashboard warnings may appear if the module shares a network with other systems.
In some cases, the vehicle may enter a reduced-power mode or limit other functions.

Common causes, most likely first

A weak or failing 12-volt battery, causing low voltage to the active steering module.
Corroded, loose, or damaged wiring or connectors at the active steering module or its power/ground points.
A blown fuse or faulty relay that supplies power to the active steering module.
A faulty active steering module, though this is less common than wiring or power issues.
Communication network faults, such as a shorted or open data bus wire, affecting module messages.
Poor ground connection for the active steering module or the network it uses.
Aftermarket accessories or improper electrical repairs that interfere with the communication bus.

How to diagnose and fix it

Check the battery voltage and state of charge; recharge or replace the battery if it is weak.
Inspect and test the fuses and relays that supply power to the active steering module.
Visually inspect the wiring and connectors at the active steering module for corrosion, damage, or looseness.
Perform a voltage drop test on the power and ground circuits to the module to confirm they can carry current.
Use a scan tool to check for communication on the data bus and to see if other modules can communicate with the active steering module.
If communication is still absent, check the data bus wiring for shorts or opens between the module and the network.
If all external checks pass, replace and reprogram the active steering module as the last step.

Before you replace the steering module

A weak battery is a leading cause of this code because the active steering module may shut down or fail to communicate when voltage drops during cranking.
Corroded ground connections, especially those shared with other modules, often cause communication codes without any obvious steering symptoms.
The code does not always mean the module is faulty; many times, the problem is a simple blown fuse or a loose connector that can be fixed at low cost.
Aftermarket electrical accessories, such as phone chargers or alarm systems, can interfere with the communication bus and trigger this code.
Some vehicles require the active steering module to be initialized or calibrated after replacement, so a new module may still set the code if not properly programmed.

Can I keep driving with C0700?

If the steering feels normal, you can drive cautiously to a repair shop, but avoid high speeds and heavy steering loads. If the steering assist is reduced or intermittent, stop driving and have the vehicle towed to prevent loss of control.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.