P1403 — VVT Solenoid B Circuit High Input

What is the most common cause of P1403?

The most common causes are: faulty camshaft position sensor, damaged sensor wiring or reluctor ring, worn cam phaser.

How much does it cost to fix P1403?

Replace the camshaft position sensor — $120–$350; Replace the VVT oil control valve — $200–$500; Timing chain/belt repair — $800–$2,500. Exact cost depends on the root cause, your vehicle and local labor rates — a proper diagnosis is the cheapest first step.

Will P1403 clear itself?

Sometimes P1403 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.

How do I diagnose P1403 myself?

Start with a scan: confirm P1403, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the VVT solenoid b, and verify the suspect component against live data before buying parts.

Is it safe to drive with P1403?

Drive with caution. The engine may run poorly or enter a failsafe mode; if timing has jumped, continued driving risks severe valve damage on interference engines. Diagnose before any long trip.

The stored fault code P1403 points to an electrical problem within the variable valve timing system, specifically affecting the B circuit. When the powertrain control module detects an abnormally high voltage signal on this circuit—readings that sit dangerously close to full battery voltage—it logs P1403 and triggers the check engine light. This is not a mechanical failure in the traditional sense; rather, it is the electrical symptom of something going wrong in the wiring, ground path, or the solenoid component itself.

Variable valve timing works by using oil pressure to adjust the relationship between the camshaft and crankshaft, which optimizes valve timing for different engine speeds and loads. The VVT solenoid acts as a control valve, directing pressurized oil to either advance or retard the camshaft phaser. For this system to function, the control module must be able to send and receive proper electrical signals through the solenoid circuit. When that circuit reads high instead of the expected pulsing signal, the module cannot command proper timing adjustments, and the engine falls back to a default calibration that sacrifices performance and efficiency.

The control module continuously monitors this circuit during normal operation. If the abnormal voltage persists long enough across multiple drive cycles, the module confirms the fault is genuine and not a momentary electrical glitch, then permanently stores P1403 along with a freeze frame snapshot of engine conditions at the moment of detection. That snapshot—showing RPM, load, temperature, and vehicle speed—becomes the starting point for any serious diagnosis.

Common Symptoms of P1403

The Check Engine Light will illuminate as the most obvious indicator that P1403 has been stored. Beyond the warning lamp, drivers typically notice a measurable loss of engine power, particularly under acceleration. The idle may become rough or unstable, and low-end torque suffers noticeably during normal driving maneuvers. Cold starts often become problematic, with the engine either refusing to fire immediately or requiring extended cranking before catching. In the most severe cases, the engine may not start at all, especially if the VVT malfunction causes timing to fall completely out of phase. Fuel economy often drops as the engine compensates poorly for the lost variable timing capability.

Common Causes of P1403

The most frequent culprit behind P1403 is a signal wire that has shorted directly to battery positive voltage, bypassing the control module's intended signal path. A failed VVT solenoid B can also pull the circuit high internally, giving the module a false reading even when wiring is intact. An open or corroded ground return for the solenoid prevents proper circuit completion, which can sometimes manifest as high-side voltage readings depending on how the module samples the circuit. Faulty wiring harness insulation, especially in areas exposed to engine heat or road debris, creates intermittent or permanent shorts. A defective camshaft position sensor may send corrupted data that the module misinterprets as a VVT circuit fault. VVT oil control valves can become stuck or clogged with sludge, causing the hydraulic response to lag or fail, which the electrical monitoring system sometimes translates into circuit complaints. Worn timing chain components or a jumped timing belt can mechanically disrupt cam position signals enough to trigger related fault codes alongside P1403.

How to Diagnose P1403

Begin by connecting an OBD2 scanner and confirming that P1403 is the primary stored code, then record all available freeze frame data before clearing anything—this information reveals exactly what conditions existed when the module first detected the fault. Review any other stored codes for patterns; codes related to camshaft position, engine timing, or oil pressure often point toward the root cause rather than the circuit symptom. Check for any manufacturer technical service bulletins specific to your vehicle's make, model, and model year, as software updates or known fixes may apply. Perform a thorough visual inspection of the wiring harness and connectors associated with the VVT solenoid B circuit, looking for chafed insulation, melted connectors, corrosion buildup, or loose terminals. With the VVT solenoid B disconnected, use a multimeter to measure voltage at the harness connector; a high reading with the component unplugged confirms a short to power in the wiring itself, while a normal reading that drops to near-zero indicates the solenoid has failed internally. Always verify engine oil level and condition, since VVT systems depend entirely on clean, pressurized oil, and dirty or low oil will cause performance faults even when electrical readings appear correct. Finally, clear the code and operate the vehicle through a complete drive cycle that recreates the freeze frame conditions, then recheck for the return of P1403 to confirm whether the repair was successful.

Repair Options and Costs

Camshaft position sensor replacement typically runs between $120 and $350 for parts and labor at an independent shop. VVT oil control valve replacement, which is a common fix for this code, generally costs $200 to $500 depending on vehicle application. Timing chain or timing belt repairs, which become necessary when mechanical timing has jumped or the phaser has seized, range from $800 to $2,500 due to the significant labor involved in accessing timing components.

How Much Does Fixing P1403 Cost?

The total repair bill for P1403 varies considerably depending on which underlying component actually failed. Replacing a faulty camshaft position sensor costs $120 to $350. Installing a new VVT oil control valve typically runs $200 to $500. Full timing chain or belt repair, which may be required if timing has jumped or the phaser is mechanically damaged, ranges from $800 to $2,500. In most cases, the overall cost falls somewhere between $120 and $500 for the simpler electrical or solenoid repairs, with the higher end reserved for mechanical timing work. An accurate diagnosis before purchasing parts is essential—the most expensive repair is rarely the first one to investigate, and many P1403 codes resolve with simple solenoid or sensor replacements.

Can You Drive with P1403?

This code warrants caution. While the engine may continue operating in a reduced-power failsafe mode, the underlying timing disruption can cause rough running, poor acceleration, and increased fuel consumption. If the fault has allowed timing to jump significantly, continued operation on interference engines risks contact between valves and pistons, resulting in catastrophic internal damage. Address the diagnosis before taking any long trips, and prioritize repairs if any loss of power or abnormal engine behavior is noticed during normal driving.

Related OBD2 Codes

• P1400: Glow Plug Monitor Fault (Bank #1)
• P1401: Glow Plug Monitor Fault (Bank #2)
• P1402: System Voltage Out Of Self Test Range
• P1404: Glow Plug Circuit High Side
• P1405: DPFE Circuit Low Input
• P1406: DPFE Circuit High Input