OBD-II trouble code
U042F: Invalid Data Received From Camshaft Position Control Module
A module is receiving messages from the camshaft position control module, but the data inside them is implausible or out of range. The link is alive — the content is wrong. Can affect variable valve timing and driveability.
Quick facts
- System
- Network
- Category
- Network Communication
- Severity
- Medium severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $100 – $1,200
- DIY difficulty
- Shop recommended
What does U042F mean?
The camshaft position control module handles variable valve timing (VVT) — it reads camshaft position sensors, compares cam timing to crankshaft position, and commands the cam phasers or actuators that advance and retard valve timing to balance power, economy, and emissions across the rev range. On vehicles that break this out as its own controller, it broadcasts cam position and VVT status to the ECM and other modules over the network. U042F sets when a receiving module is still hearing from the camshaft position control module, but the data in its messages is invalid: a value is out of range, implausible, or contradicts what the crankshaft signal and other modules see. The connection is alive; the content can't be trusted. That is the key difference from a lost-communication code, which means the module has gone completely silent.
Because the fault is bad data rather than a dead bus, the causes cluster around whatever makes the module broadcast wrong information. The most common source is the VVT hardware and its sensors: a failing camshaft position sensor, a stuck or sludge-clogged VVT/oil-control solenoid, low or dirty engine oil starving the phasers, or a worn phaser can all push the module into reporting implausible cam timing. Low system voltage is a classic trigger, since module logic gets unreliable as voltage sags. The module's own software can be at fault if it is outdated, corrupted, or was never properly programmed after a replacement, and corroded connectors or chafed wiring near the engine can corrupt otherwise-good messages in transit.
Symptoms often reach into driveability because valve timing directly affects how the engine runs. You may see a check engine light, rough idle, hesitation or reduced power, poorer fuel economy, and sometimes a rattle at start-up if a phaser is involved — and in many cases companion VVT or camshaft codes (the P0010-P0014 / P0016-P0019 family) are stored alongside U042F and point straight at the mechanical fault. The car usually stays driveable because the engine falls back to a safe default timing strategy, but performance and economy can suffer, so it is worth addressing promptly. Because U042F is frequently a secondary code, read the full list — a companion VVT or cam/crank correlation code often names the real root cause.
Common causes
- Failing camshaft position sensor feeding implausible timing data
- Stuck, dirty, or sludge-clogged VVT / oil-control solenoid
- Low, dirty, or degraded engine oil starving the cam phasers
- Worn or faulty camshaft phaser / VVT actuator
- Low system voltage or a weak battery/charging system
- Outdated, corrupted, or mismatched camshaft position control module software
- Corroded connectors or chafed wiring near the engine corrupting messages
- Camshaft position control module internal fault
Symptoms
- Check engine light, often with companion VVT or cam/crank correlation codes
- Rough or unstable idle
- Hesitation, stumble, or reduced engine power
- Reduced fuel economy
- Rattle or noise at start-up when a phaser is involved
- Vehicle driveable in a default valve-timing fallback with reduced performance
Diagnostic steps
- 1.Read ALL stored codes first — U042F is often secondary to a VVT or cam/crank correlation code (P0010-P0019 family) that names the mechanical fault.
- 2.Check engine oil level and condition; low or dirty oil is a leading cause of VVT faults.
- 3.Check battery and charging system voltage; low voltage is a common cause of implausible module data.
- 4.Use live data to compare commanded versus actual camshaft timing and watch the cam position signal.
- 5.Test the VVT/oil-control solenoid resistance and operation, and inspect for sludge.
- 6.Inspect the camshaft position sensor and its wiring/connector for damage and corrosion.
- 7.Verify the module has the correct, current calibration, then address any companion codes before condemning the module.
Repair cost
$100 – $1,200
Cost depends on what is producing the bad data. A camshaft position sensor is often $120-$350 installed. A VVT / oil-control solenoid is commonly $150-$450 installed. An oil and filter change to restore VVT operation is modest, $60-$150. A worn camshaft phaser is the expensive mechanical case, frequently $600-$1,200+ with labor. A module reflash is $100-$300, and camshaft position control module replacement with programming runs $400-$900 — but that should only follow thorough diagnosis, since U042F is frequently a secondary code.
Estimate your repair
Run the numbers for your vehicle
Open the Repair Cost Estimator with module communication / can bus diagnosis preselected. Adjust labor rate and vehicle category to fit your situation.
DIY vs shop
Leave this one to a qualified shop. It typically involves emissions-critical components, refrigerant handling, or other work that requires manufacturer-grade tooling, training, or certification. DIY attempts often produce a more expensive problem than the original code.