P0346 on 2013 Scion FR-S: Camshaft Sensor 'A' (Bank 2) Causes and Fixes

What's Unique About the 2013-2013 Scion FR-S

The 2013 Scion FR-S is particularly known for this issue due to a Technical Service Bulletin (TSB S-SB-0013-14) issued for early production models. This TSB, which also applies to its twin, the Subaru BRZ (under TSB 11-130-13R), states that vehicles produced before VIN JF1ZAA1#D#721474 may set camshaft sensor codes because the clearance between the sensor and the camshaft timing gear is out of specification. This means the problem is often a known manufacturing tolerance issue, not just a random part failure, and may be fixed by installing a 0.2 mm shim rather than replacing the sensor itself.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Symptoms You May Notice

• Check Engine Light is on
• Engine stalling, especially at idle or when coming to a stop
• Rough idle, sometimes with severe shaking
• Extended cranking or difficulty starting the engine
• Engine hesitation or stumbling during acceleration
• Reduced engine power and sluggish performance
• Decreased fuel economy
• Traction control/slip light may also illuminate along with the Check Engine Light

Most Likely Causes

1. Faulty Intake Camshaft Position Sensor (Bank 2) 🔴 High Probability → Shop Engine Camshaft Position Sensor A manufacturer TSB (S-SB-0013-14) specifically calls out that the sensor clearance can be out of specification on 2013 models, leading to signal errors. Over time, heat and vibration can also cause the sensor's internal electronics to fail. Oil leaking onto the sensor connector can also cause a short.
   How to confirm: Swap the driver's side intake sensor (Bank 2) with the passenger's side intake sensor (Bank 1), as they are identical parts. Clear the codes and drive the vehicle. If the code changes to P0341 (the equivalent code for Bank 1), the sensor is confirmed to be faulty. This is a widely documented diagnostic step on owner forums.
   Typical fix: Replace the faulty camshaft position sensor. The sensor is held by a single 10mm bolt. In cases covered by the TSB for early 2013 models, a 0.2 mm shim (Part Number SU003-02910) may need to be installed between the sensor and the timing cover to correct the air gap.
   Est. part cost: $65 - $125
2. Damaged Wiring or Connector 🟡 Medium Probability The engine bay is compact, and wiring can become brittle over time from heat cycles. The connector clip is plastic and can break easily during removal, leading to a poor connection.
   How to confirm: Visually inspect the wiring harness and connector for the Bank 2 intake camshaft position sensor. Check for signs of chafing, melting, corrosion, or oil contamination. Wiggle the connector with the engine running to see if it causes a stall. Use a multimeter to check for proper voltage (typically a 5V reference and ground) and signal at the connector.
   Typical fix: Repair the damaged section of the wiring harness or replace the connector pigtail. If the connector clip is broken, it may need to be secured with a zip tie as a temporary measure, but replacement is recommended.
   Est. part cost: $10 - $50

Rare But Worth Checking

• Timing Chain or VVT Phaser Issue: → Shop Engine Timing Chain While less common than a sensor failure, a stretched timing chain or a malfunctioning VVT (Variable Valve Timing) phaser can cause the camshaft timing to be out of sync with the crankshaft, triggering this code. This is a more significant mechanical repair and would likely be accompanied by other timing-related codes or engine noises.
• Failing Engine Control Module (ECM): This is extremely rare. The ECM should only be considered as the cause after all other possibilities, including sensors, wiring, and mechanical timing, have been thoroughly ruled out. Early 2013 models also had ECU mapping issues that caused rough idle, but these were typically addressed by a dealer reflash and associated with different codes like P0019.

Diagnosis Steps

1. Read the trouble code using an OBD-II scanner and confirm P0346 is present. Note any other codes.
2. Visually inspect the Bank 2 (driver's side) intake camshaft position sensor and its electrical connector. It is located on the front of the engine on the driver's side cylinder head. Look for obvious damage, corrosion, or oil leaks.
3. For a definitive diagnosis, swap the Bank 2 intake sensor with the Bank 1 (passenger side) intake sensor. They are identical parts and each is held by a single 10mm bolt.
4. Clear the DTCs using the scanner.
5. Start the engine and test drive the vehicle, allowing it to reach operating temperature.
6. Re-scan for codes. If code P0341 (Bank 1 Intake Sensor Performance) now appears, the sensor you moved is faulty and needs to be replaced.
7. If code P0346 returns, the problem is likely in the wiring to the Bank 2 sensor, the sensor clearance (on early 2013 models), or, rarely, the ECM.
8. If the code does not return, the issue may have been an intermittent poor connection that was resolved by reseating the connector.
9. If you have an early 2013 model (pre-VIN ...721474), and P0346 returns after the swap, the next step according to TSB S-SB-0013-14 is to check the sensor-to-gear clearance and potentially install a 0.2mm shim.

Parts You'll Likely Need

• Intake Camshaft Position Sensor (OEM #SU003-00414) — This is the most common failure point for code P0346, especially on 2013 models, as documented by a manufacturer TSB. The four cam sensors on the engine are identical and interchangeable.
  Trusted brands: Denso (OEM supplier), NTK, Standard Motor Products (SMP)
  OEM price range: $100 - $126
  Aftermarket price range: $65 - $95

Related Codes That Often Appear With This One

• P0345 — This is the circuit malfunction code for the same sensor (Bank 2 Intake). P0346 is for range/performance, so they often appear together if the sensor signal is completely lost.
• P0340, P0341 — These are the equivalent codes for the Bank 1 (passenger side) intake camshaft sensor. Seeing them together could indicate a widespread sensor or wiring issue, or that a faulty sensor was swapped from Bank 2 to Bank 1 during diagnosis.
• P0365, P0366, P0390, P0391 — These codes relate to the exhaust camshaft position sensors. The TSB for the 2013 FR-S (S-SB-0013-14) groups all cam sensor codes together, as the sensor clearance issue could affect any of the four sensors.
• P0302, P0304 — These are misfire codes for cylinders on Bank 2 (driver's side). An incorrect camshaft position signal can disrupt timing and cause misfires on the affected bank. The TSB also lists these codes as potential companions.

Technical Service Bulletins (TSBs) & Recalls

• S-SB-0013-14 (Scion): Addresses hard starting, rough idle, and various camshaft sensor or misfire DTCs (including P0346) due to incorrect camshaft position sensor clearance on vehicles built before VIN ...721474.
• 11-130-13R (Subaru): The equivalent TSB for the Subaru BRZ, covering the exact same issue and codes, confirming it's a platform-wide problem for the FA20 engine in that model year.

Platform-Specific Known Issues

• A Technical Service Bulletin (S-SB-0013-14, superseding S-SB-0033-13) was issued for 2013 FR-S models produced before VIN JF1ZAA1#D#721474 for camshaft sensor codes, including P0346. The bulletin notes that the clearance between the sensor and the timing gear may be out of spec, causing signal issues. The fix involves installing a 0.2 mm shim (Part Number SU003-02910) and does not require replacing the sensor unless it has failed separately.
• The 2013 model year was also subject to a valve spring safety recall which could cause similar symptoms like stalling. It is critical to ensure this recall has been performed.

Mechanic-Grade Diagnostic Values

• Camshaft Position Sensor Resistance — expected: 835 - 1,400 Ohms (at 68°F / 20°C). Failure: A reading outside of this range indicates a faulty sensor.
• Sensor Connector Voltage (Key On, Engine Off) — expected: Pin 1 (Power): ~12V (Battery Voltage), Pin 2 (Signal): Varies, Pin 3 (Ground): ~0V. Failure: No voltage on Pin 1 suggests a problem with the EFI MAIN1 relay or its circuit. An incorrect signal voltage can point to a sensor or ECM issue.
• Sensor Air Gap (for early 2013 models pre-VIN ...721474) — expected: 1.3 ± 0.05 mm (1.25 to 1.35 mm). Failure: If the measured gap is outside this range (e.g., 1.12 mm), a shim is required to correct it as per the TSB.

Scan Tool Commands That Help

• Techstream: All Readiness — After a repair, use this function and input DTC P0346 to check the DTC judgment result. It will show NORMAL, ABNORMAL, or INCOMPLETE, confirming if the fix was successful without extensive driving.
• Techstream: Read Freeze Frame Data — When P0346 is first detected, reading the freeze frame data is critical. It captures engine parameters (RPM, coolant temp, vehicle speed) at the exact moment the fault occurred, helping to identify conditions that trigger the code.

Wiring & Ground Locations

• Engine Ground Straps — There are three primary engine grounds: one on each frame rail near the bottom front of the engine, and a critical one from the top rear of the passenger side of the engine/transmission to the transmission tunnel.. The ground strap on the passenger side is often forgotten or improperly reinstalled after clutch or transmission work. A poor ground connection can introduce electrical noise into the system, causing sensor signals to become erratic and triggering performance codes like P0346 even if the sensor and its direct wiring are good.
• ECM (Engine Control Module) — Located at the right end of the dash, accessible from the passenger footwell.. This is the termination point for the camshaft position sensor wiring. When testing for continuity or shorts in the harness, one end of the multimeter will connect to the sensor plug and the other to the corresponding pins at the ECM connector.

Real Owner Repair Stories

• ft86club.com forum user (2013 Scion FR-S) — Car would crank but not start, throwing multiple camshaft position sensor codes including P0345 and P0340, along with crank sensor code P0335.
  ❌ Tried (didn't work) Replacing the camshaft position sensors., Replacing the crankshaft position sensor.
  ✅ What actually fixed it The issue was traced back to a botched valve spring recall service performed by a dealer. The technician had failed to properly reinstall the timing components, causing the cam and crank signals to be out of sync. A different, more competent dealer had to re-time the engine correctly to resolve the codes.

OEM Part Supersession History

• Not specified, but early parts led to TSB. → SU003-00414 (Scion/Toyota) / 22056AA260 (Subaru) — The sensor itself is generally reliable, but the TSB for early 2013 models indicates a system-level tolerance issue, not necessarily a faulty part design that was superseded. SU003-00414 is the standard replacement part for all 2013-2016 models.
  Heads up: The four camshaft position sensors on the FA20 engine are physically identical and interchangeable for diagnostic purposes (e.g., swapping intake to exhaust, or bank-to-bank).

Model Year Variations Within This Range

• Early 2013: Vehicles produced before VIN JF1ZAA1#D#721474 are subject to TSB S-SB-0013-14, which indicates the root cause of P0346 may be an incorrect air gap for the sensor. The fix is to measure the gap and install a shim, rather than replacing the sensor. Later 2013 models and beyond do not have this specific manufacturing tolerance issue.