C1278 — STEERING Wheel Angle 1and 2 Signal Faulted

C1278 — STEERING Wheel Angle 1and 2 Signal Faulted. A fault in the sensor and actuator circuits. The car is usually drivable while you plan the repair. Typical causes: open or shorted wiring in the circuit, corroded, loose or damaged connector, blown fuse feeding the circuit.

chassis (brakes/steering/suspension)

Is it safe to drive?

Short-term driving is OK In most cases the car remains drivable, possibly with reduced performance or a disabled auxiliary system. If symptoms include stalling, no-start or brake/steering warnings, treat it as urgent.

How to diagnose with an OBD scanner

Read the code and freeze frame Connect an OBD2 scanner, confirm C1278 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
Check for companion codes and TSBs Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many C0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
Inspect wiring and connectors Visually inspect the wiring harness and connectors related to the STEERING wheel angle 1and 2 signal faulted for damage, corrosion, chafing or poor contact.
Subsystem check Measure reference voltage, ground and signal continuity at the component connector.
Subsystem check Wiggle-test the harness while watching the signal in live data — dropouts reveal broken wires.
Verify the repair Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm C1278 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for C1278 (parts and labor, USD, independent shop rates): Repair wiring or connectors: $80–$250; Control module repair: $300–$1,000; Replace the faulty sensor or actuator: $150–$500. Overall, fixing C1278 usually costs between $80 and $1,000. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.

Common questions

What are the symptoms of C1278?

Drivers most often notice: the affected system operates intermittently or not at all, increased fuel consumption in some cases, possible limp mode depending on the affected component, Check Engine Light on.

Will C1278 clear itself?

Sometimes C1278 clears after a few drive cycles if the fault was intermittent — for example a loose connector or a tank of bad fuel. The underlying cause usually remains, so the code tends to return. Clear it once; if it comes back, diagnose rather than erase it repeatedly.

Is it safe to drive with C1278?

In most cases the car remains drivable, possibly with reduced performance or a disabled auxiliary system. If symptoms include stalling, no-start or brake/steering warnings, treat it as urgent.

How much does it cost to fix C1278?

Repair wiring or connectors — $80–$250; Control module repair — $300–$1,000; Replace the faulty sensor or actuator — $150–$500. Exact cost depends on the root cause, your vehicle and local labor rates — a proper diagnosis is the cheapest first step.

How do I diagnose C1278 myself?

Start with a scan: confirm C1278, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the sensor and actuator circuits, and verify the suspect component against live data before buying parts.

When your vehicle's computer decides something is wrong with the steering wheel angle sensing system, it speaks up by storing trouble code C1278. This specific code indicates that the steering wheel angle sensor is sending a faulted signal — essentially, the data coming from the sensor doesn't match what the control module expects to see. The chassis control system, which oversees brakes, steering, and suspension functions, constantly validates these readings while you drive. When the signal falls outside acceptable parameters for too long across multiple drive cycles, the module logs C1278 and illuminates the warning light on your dashboard.

The steering wheel angle sensor plays a supporting role in several vehicle systems, including stability control, traction control, and sometimes electric power steering. It measures the rotational position of the steering wheel and reports that information back to various control units. When the signal becomes corrupted, inconsistent, or disappears entirely, those dependent systems may still function in a limited capacity, or they may activate protective limp-home modes. The stored freeze frame data alongside C1278 is valuable — it captures the exact vehicle conditions (engine speed, load, temperature, vehicle speed) when the fault first appeared, giving you a starting point for tracking down what went wrong.

Symptoms of C1278

The stability control or traction control system may behave erratically or disable themselves entirely
The steering angle sensor-related functions operate inconsistently or stop responding
You may notice slightly higher fuel consumption due to compensatory changes in how the engine and transmission respond
The instrument cluster displays a warning light related to stability, ABS, or steering systems
Some vehicles enter a reduced-power or limp mode, limiting acceleration and top speed
The electric power steering feel may change, becoming heavier or less responsive than normal
In rare cases, the start/stop system or other auxiliary features stop working

Common Causes of C1278

Corrosion, looseness, or physical damage at the steering angle sensor connector
A weak or interrupted ground connection serving the sensor or its control circuit
Broken, chafed, or shorted wiring within the sensor circuit
Internal failure within the steering angle sensor itself
A fault in the control module that processes the steering angle signal
Water intrusion into the sensor housing, especially in vehicles exposed to heavy rain or car washes
Mechanical binding or damage to the steering column where the sensor is mounted

How to Diagnose C1278

Start by connecting a quality OBD2 scanner and retrieve all stored codes, paying special attention to C1278. Save the freeze frame data associated with this code — it tells you what the engine and vehicle were doing when the fault occurred, which often points you toward the root cause.
Check for any technical service bulletins (TSBs) specific to your vehicle make, model, and year. Search using your VIN on the manufacturer website or NHTSA database — many steering angle sensor issues have documented factory fixes or software updates that solve the problem without any physical repair.
Perform a thorough visual inspection of the wiring harness and connectors related to the steering angle sensor. Look for damaged insulation, corroded pins, loose connections, or evidence of water entry. The sensor is typically mounted on or near the steering column.
With the connector unplugged, use a multimeter to check for proper reference voltage at the sensor, verify solid ground continuity, and confirm signal wire integrity. Compare your readings to the manufacturer's specifications for your vehicle.
Reconnect everything and perform a wiggle test on the harness while monitoring the steering angle data in live scanner view. Any dropouts, spikes, or sudden jumps indicate an intermittent wire break or poor connection that needs repair.
After clearing the code, drive the vehicle through a complete drive cycle that reproduces the conditions recorded in the freeze frame data. If C1278 does not return, the issue may have been temporary. If it comes back, you have confirmed an active fault requiring repair.

Repair Options and Costs

Addressing C1278 typically involves one of three approaches, starting with the least expensive:

Wiring and connector repair: Fix damaged wires, replace corroded terminals, or seal a leaking connector. This is usually the culprit and costs $80–$250 for parts and labor.
Steering angle sensor replacement: If the sensor itself has failed internally, expect to pay $150–$500 for a new or remanufactured unit plus installation labor.
Control module repair or replacement: When the chassis control module is at fault, repair costs typically run $300–$1,000 depending on whether the module can be rebuilt or must be replaced outright.

Total repair costs for C1278 generally fall between $80 and $1,000 depending on which component is actually at fault. An accurate diagnosis before purchasing parts always saves money — the most expensive repair scenario is rarely where you should start.

Can You Drive with C1278?

Most vehicles remain drivable when C1278 is active, though you may experience reduced system functionality or slightly diminished performance. However, if the fault causes stalling, prevents the engine from starting, or triggers warnings about brake or steering systems, treat it as urgent and have it diagnosed promptly. Safety systems like electronic stability control may be disabled until the fault is cleared.