U0412 indicates a control module received steering angle sensor–identified data that failed format or plausibility checks on the vehicle network. This is a network-level message fault, not confirmation of a bad sensor or module, and the exact interpretation can vary by make, model, and year. You should test electrical circuits and Controller Area Network (CAN) communication to confirm whether the fault stems from wiring/connectors, a sensor plausibility issue, power/ground problems, or a module input-stage or processing discrepancy.
What Does U0412 Mean?
This article follows SAE J2012 formatting conventions; SAE J2012 defines DTC structure and some standardized descriptions and the SAE J2012-DA digital annex contains published descriptor text. U0412 is a U-series network message classification that indicates invalid or implausible data identified as steering angle sensor information was received by a control module.
The code is shown here without a Failure Type Byte (FTB). If a hyphen suffix (FTB) were present it would identify a subtype or additional failure detail recorded by the OEM. Because many body and chassis networks differ by manufacturer, there is no single universal component-level definition for U0412 — interpretation and affected modules can vary by make/model/year. Confirm by measuring wiring, power/ground, and CAN message validity before assuming a specific part failure.
Quick Reference
- System: network message invalid involving steering angle sensor data
- Code format shown without an FTB; an FTB would denote a subtype if present
- Interpretation varies by make/model/year — not a guaranteed failed sensor
- Primary checks: wiring/connectors, sensor plausibility, power and ground, CAN message integrity
- Use scope or CAN logging and basic electrical tests to confirm root cause
Real-World Example / Field Notes
In the shop you’ll often see U0412 set after events that disturb network signals: battery disconnects, water intrusion at steering column connectors, or physical damage to the harness. A common pattern is intermittent U0412 that clears and returns during steering motion; this often points to chafed wiring or a poor connector making intermittent contact. Another frequent observation is persistent U0412 after replacing a steering angle sensor without verifying message plausibility at the receiving module — on some vehicles the sensor’s message ID or format must match the module’s expectations.
On vehicles with CAN diagnostics available, technicians commonly capture frames with a CAN logger and compare the steering angle message payload to a known-good sample or live reference. A failing sensor is one possible cause, but field notes emphasize checking connector corrosion, bent pins, and power/ground stability first. Low battery voltage or parasitic loads can create corrupted packets and false invalid-data events, so verify battery condition and charging system stability during testing.
Symptoms commonly reflect invalid or implausible steering angle data appearing on a Controller Area Network (CAN) or in the driver displays and stability systems. You should treat U0412 as a networked-data or message-validation fault and verify with electrical and message-level testing rather than guessing parts. Interpretation can vary by make/model/year; confirm with basic power/ground, connector, wiring continuity, and CAN/Local Interconnect Network (LIN) message traces before concluding the root cause.
Symptoms of U0412
- Warning Lamp Illumination of stability/traction/airbag/ABS warning lamps or a general vehicle fault indicator.
- Steering Assist Reduced or altered steering feel from power steering assist systems, intermittent or persistent.
- Driver Display Incorrect or fluctuating steering angle readout on the dash or instrument cluster.
- Fault Memory Persistent U0412 stored in the module memory and possibly freeze-frame or snapshot data.
- Adaptive Systems Malfunction of adaptive cruise, lane-keep, or stability control features that rely on steering angle data.
- Intermittent Faults that appear when turning, over bumps, or after a battery disconnect/voltage event.
Common Causes of U0412
Most Common Causes
- Invalid or corrupted steering angle message on the CAN bus caused by a faulty steering angle sensor or its wiring; verify with message-level traces before replacing the sensor.
- Poor power or ground at the steering angle sensor or local module leading to erroneous data; confirm with voltage and ground tests at the connector.
- Intermittent connector/contact faults or corrosion in harness plugs that cause message dropouts or data errors; inspect and wiggle-test while monitoring live data.
- CAN bus physical-layer issues (open/short/poor termination) producing corrupted frames; test with an oscilloscope or known-good scan tool showing valid CAN voltages and differential signals.
Less Common Causes
- Local module input-stage fault where the sensor data is received but not processed correctly — consider only after all external inputs test good.
- Software/configuration mismatch or calibration/learning lost after service (varies by manufacturer); confirm with OEM-level diagnostics and message plausibility checks first.
- Electromagnetic interference or aftermarket device introducing spurious signals on the bus; isolate aftermarket loads and re-test.
Diagnosis: Step-by-Step Guide
Tools: diagnostic scan tool with CAN data and freeze-frame capability, multimeter, backprobe pins or breakout box, oscilloscope (for CAN differential trace), wiring diagrams, continuity/short tester, pick/wiggle tools, connector cleaner and dielectric grease, portable power supply or jumper leads.
- Retrieve the DTC and freeze-frame with a full-function scan tool to capture vehicle state, prior to clearing codes; record mileage, ignition state, and sensor values.
- Check network health: confirm CAN battery/ignition voltages and observe CAN high/low differential with an oscilloscope or a capable scan tool; look for correct idle voltages and clean square/rounded waveforms.
- Monitor live steering angle message and related parameters on the scan tool while operating the steering slowly; look for implausible jumps, missing messages, or out-of-range values.
- Verify power and ground at the steering angle sensor connector and at the local module — measure with ignition on and while exercising the steering; log any voltage drop or intermittent loss.
- Conduct a connector and harness inspection: flex and wiggle the harness and connectors while watching live data for changes; inspect for corrosion, bent pins, or water ingress.
- Perform wiring continuity and short-to-power/ground checks between the sensor/module and the relevant module connector using a wiring diagram; repair any opens or shorts found and re-test.
- If CAN frames are corrupted or missing, isolate bus segments: disconnect modules or remove terminators per repair manual to locate the faulty node or segment using message presence testing.
- After repairs to wiring/connectors, clear codes and reproduce the original test conditions to confirm the fault does not return; verify that live data is plausible and stable across power cycles.
- If all wiring, power, ground, and bus tests pass and the message still contains invalid data from a single node, consider an input-stage or internal processing issue in that node — document all tests before replacing the module.
- When a module replacement is required, confirm post-repair that the replacement communicates correctly on the CAN, performs any required self-tests, and that the original U0412 does not recur.
Professional tip: always prove the fault by measuring message integrity and sensor plausibility first — swapping modules without verifying power, ground, and network health often wastes time and money. Use an oscilloscope to capture transient or intermittent CAN errors that a basic scanner may miss.
Possible Fixes & Repair Costs
Low: $50–$150 — Typically a connector clean, corroded pin repair, or fuse replacement. Justified when visual inspection shows corrosion, bent pins, or a blown fuse and continuity checks confirm an open feed or return. These are low-labor, test-driven fixes after you verify power/ground and CAN termination resistance.
Typical: $150–$600 — Common repairs like harness splice repairs, replacement of a single sensor commonly associated with the message, or repair of a damaged CAN/LIN segment. Justified when voltage, resistance, or signal-level tests show intermittent or out-of-spec wiring, or a single sensor’s live data stream is implausible compared with other network messages.
High: $600–$2,000+ — Module replacement or complex wiring harness replacement and labor, or diagnosis requiring dealer-level equipment. Only justified after all external inputs test good: power, ground, wiring continuity, connector integrity, and message absence or malformed CAN frames. In that case the module may have a possible internal processing or input-stage issue and replacement/programming may be required.
Factors affecting cost include access labor, number of modules or wiring runs involved, and whether dealer tools are required for programming. Always confirm repairs with replayed tests: restore the circuit, operate the system, and verify the U0412 message clears and the message content becomes plausible on a scan tool before closing the job.
Can I Still Drive With U0412?
You can usually drive, but it depends on what system used the missing or implausible message. U0412 indicates a network message was not received or was implausible; it does not by itself identify an immediate mechanical failure. However, associated safety systems (ABS, Electronic Stability Control) may enter a degraded mode if they rely on that message. Check for illuminated warnings and confirm sensor plausibility and CAN health with a scan tool before extended driving.
What Happens If You Ignore U0412?
Ignoring U0412 can leave a control function degraded or disabled without you knowing until a critical moment. You may lose redundancy in safety systems, experience unexpected behavior, or have intermittent faults that become harder to trace. Diagnose promptly with wiring and network tests to avoid cascading faults and higher repair costs.
Related Codes
- U0419 – Invalid Data Received From Steering Effort Control Module
- U0418 – Invalid Data Received From Brake System Control Module
- U0417 – Invalid Data Received From Park Brake Control Module
- U0416 – Invalid Data Received From Vehicle Dynamics Control Module
- U0414 – Invalid Data Received From Four-Wheel Drive Clutch Control Module
- U0413 – Invalid Data Received From Battery Energy Control Module B
- U0411 – Invalid Data Received From Drive Motor Control Module
- U0409 – Invalid Data Received From Alternative Fuel Control Module
- U0408 – Invalid Data Received From Throttle Actuator Control Module
- U0407 – Invalid Data Received From Glow Plug Control Module
Key Takeaways
U0412 is a network message plausibility fault defined by SAE J2012; it flags an implausible or missing message rather than a specific failed part. Interpretation varies by make/model, so confirm with electrical and CAN/LIN testing. Prioritize inspecting connectors, power/ground, and message content on a scan tool. Replace wiring or modules only after external inputs and network integrity are proven good. Use test measurements and plausibility checks to guide a targeted, cost-effective repair.
Vehicles Commonly Affected by U0412
U0412 is frequently reported on vehicles from manufacturers with distributed networked control architectures, including European, Asian, and North American brands. It is commonly seen on models with multiple control modules and advanced driver assistance systems because they exchange many messages across CAN or LIN. Network complexity, module count, and long wiring harnesses increase the chance of message implausibility being logged.
FAQ
Can I clear U0412 and see if it returns?
Yes, you can clear the code with a scan tool, but this is only a temporary step. Clearing helps determine if the fault is intermittent. After clearing, drive under conditions that normally reproduce the fault and monitor live data and Mode 06 or freeze-frame where available. If U0412 returns, capture time, conditions, and live CAN message snapshots to guide targeted testing of wiring and node behavior.
Is special equipment required to diagnose U0412?
Basic diagnosis needs a quality scan tool that shows live CAN/LIN messages and module status, a digital multimeter, and preferably an oscilloscope for signal-level checks. Advanced cases may require manufacturer-level diagnostics or CAN bus analyzers to capture malformed frames. Start with power/ground checks and live data plausibility; escalate to higher-level tools only if network frames look abnormal after those checks.
Can a bad ground cause U0412?
Yes. Faulty grounds can corrupt sensor signals or module operation and cause messages to be missing or implausible on the network. Test any suspect ground with voltage drop and continuity tests while the system is powered and operating. If grounding improves and messages become plausible, a ground repair is justified rather than replacing downstream modules or sensors.
How long should a proper diagnosis take?
Diagnosis time varies but a focused, test-driven approach often takes 1–4 hours. Quick cases (visible connector corrosion, a blown fuse) can be resolved in under an hour. Intermittent or network-level faults that require logging, oscilloscope captures, or module bench testing will take longer. Allocate time for verifying power, ground, wiring continuity, and capturing live CAN data before concluding root cause.
Will replacing a sensor fix U0412?
Only if testing shows that the sensor’s output is out-of-spec or absent while wiring and power/ground are good. Replace a sensor when voltage, resistance, or live-data comparisons prove the sensor is implausible versus other known-good inputs. If sensor and wiring test normal, do not replace it; continue testing the network and control module inputs, since the issue may be a wiring, connector, or possible internal processing or input-stage issue in a module.