P0201 on 2014-2016 Mazda 6 Skyactiv-G 2.5L: Injector Circuit Fault Causes and Fixes

What's Unique About the 2014-2016 Mazda 6

While P0201 typically points to a bad injector or wiring, this is often not the case for the 2014-2016 Mazda 6 and its platform mates (Mazda 3, CX-5). Mazda issued a Technical Service Bulletin (TSB 01-017/16, later updated to 01-004/17) for an issue where an internal failure in DENSO-made PCMs causes this code to appear, specifically paired with code P0204. Mistaking this for a simple injector problem is a common and costly misdiagnosis. If you see both codes, the PCM is the primary suspect.

Symptoms You May Notice

• Check Engine Light is on
• Rough, unstable idle
• Engine runs rough and hesitates during acceleration
• Reduced engine power
• Noticeable engine misfire
• Increased fuel consumption

Most Likely Causes

1. Internal Powertrain Control Module (PCM) Failure 🔴 High Probability → Shop Engine Control Module (ECM) A known defect with the injector driver circuit inside DENSO-produced PCMs installed in this vehicle generation, as documented in Mazda TSB 01-004/17. The bulletin applies to Japan-built models with a VIN lower than JM1GJ**484154 (produced before May 23, 2016).
   How to confirm: Check for accompanying codes. If P0201 is stored along with P0204, this is the most likely cause. A technician must visually inspect the PCM's label to confirm it is a DENSO unit, as Mitsubishi also supplied PCMs which are not affected by this TSB.
   Typical fix: Replace the Powertrain Control Module (PCM). The new unit must be programmed to the vehicle by a dealer or qualified shop with Mazda-specific software.
   Est. part cost: $600-$1300
2. Faulty Cylinder 1 Fuel Injector 🟡 Medium Probability → Shop Fuel Injector Skyactiv-G direct injection engines can be susceptible to carbon buildup, and injectors can fail electrically over time.
   How to confirm: This is more likely if P0201 appears alone. Swap the cylinder 1 fuel injector with the injector from another cylinder (e.g., cylinder 2). Clear the codes and run the engine. If the code changes to P0202 (Injector Circuit/Open - Cylinder 2), the injector is faulty. You can also test the injector's resistance with a multimeter; it should be between 1.74 and 2.04 ohms at 20°C (68°F). A reading of 0 ohms (short) or OL (open) indicates a bad injector. 🎬 Watch: How to diagnose and fix a P0201 code
   Typical fix: Replace the faulty fuel injector. It is sometimes recommended to replace all four for balanced performance.
   Est. part cost: $70-$150
3. Wiring Harness or Connector Issue ⚪ Low Probability
   How to confirm: Visually inspect the wiring harness and connector for the cylinder 1 fuel injector for any signs of damage, corrosion, or loose pins. Perform a continuity test on the power and signal wires between the PCM connector and the injector connector to check for an open or short circuit.
   Typical fix: Repair or replace the damaged section of the wiring harness or the connector.
   Est. part cost: $10-$50

Diagnosis Steps

1. Scan for Codes: Use an OBD-II scanner to confirm P0201 and check for any other codes. Note if P0204 is present.
2. Check for TSB: If P0201 and P0204 are present together, stop. The most likely cause is the PCM failure described in TSB 01-004/17. Verify if your vehicle's VIN (must be lower than JM1GJ**484154) and PCM manufacturer (must be DENSO) match the TSB criteria. If so, proceed with PCM replacement.
3. Inspect Wiring (if P0201 is alone): If only P0201 is present, turn off the vehicle and inspect the wiring and connector at the cylinder 1 fuel injector for any visible damage, corrosion, or loose connections.
4. Test the Injector: If the wiring looks good, test the injector. The easiest way is to swap the cylinder 1 injector with the cylinder 2 injector. Clear the codes, start the engine, and see if the fault code changes to P0202. If it does, the injector is bad. Alternatively, measure the injector's resistance with a multimeter. It should be 1.74–2.04 ohms.
5. Test the Circuit: If the injector swap does not move the code, the problem is likely in the wiring. Perform a continuity test on the two wires running to the injector to check for an open or short circuit between the injector connector and the PCM.
6. Suspect PCM (if all else fails): If the injector and wiring are confirmed to be good, and P0201 is the only code, the PCM's internal driver for that cylinder may have failed, even without the accompanying P0204 code.

Parts You'll Likely Need

• Powertrain Control Module (PCM) (OEM #PE22-18-881 (example, part varies by VIN, check with dealer)) — This is the most common cause if P0201 is paired with P0204, due to a known manufacturer defect detailed in a TSB.
  Trusted brands: Mazda (OEM)
  OEM price range: $800-$1300
  Aftermarket price range: $600-$900 (Remanufactured)
• Fuel Injector (OEM #PY01-13-250) — This is the likely culprit if P0201 appears by itself, after ruling out wiring issues.
  Trusted brands: Mazda (OEM), Bosch, Hitachi
  OEM price range: $150-$250
  Aftermarket price range: $70-$150

Related Codes That Often Appear With This One

• P0204 — This is the strongest indicator of the known PCM failure. The internal fault in the DENSO PCM often affects the injector driver circuits for cylinders 1 and 4 simultaneously.
• P0301 — This code means 'Cylinder 1 Misfire Detected'. Since P0201 indicates a fault in the fuel injector circuit, cylinder 1 is not receiving the correct amount of fuel, which directly causes a misfire. This code is usually stored at the same time.
• P0304 — If P0204 is also present due to the common PCM fault, a cylinder 4 misfire code is also very likely to be stored.

Technical Service Bulletins (TSBs) & Recalls

• 01-004/17 (supersedes 01-017/16): 'ENGINE RUNS ROUGH AND CHECK ENGINE LIGHT ON WITH DTCS P0201 AND P0204 OR P0202 AND P0203'. This TSB identifies an internal PCM failure in DENSO units as the cause and affects certain 2014-2016 Mazda 6, 2014-2016 Mazda 3, and 2013-2016 CX-5 vehicles.
• TSB Bulletin #01-004-17-3317a: Notes that some vehicles may experience a rough running engine and the check engine light on with DTCs P0201 and P0204 or P0202 and P0203, often with misfire-related DTCs (P0301-P0304) stored simultaneously.

Platform-Specific Known Issues

• A significant number of 2014-2016 Mazda 6 models (and related Mazda3/CX-5s) with DENSO-made PCMs are prone to an internal PCM failure that specifically causes injector circuit codes P0201 and P0204 to appear together. This is documented in Mazda TSB 01-017/16 and its successor, 01-004/17.
• Manufacturer TSB Bulletin #01-004-17 confirms this multi-model issue where the engine runs rough and the check engine light illuminates specifically with DTCs P0201 and P0204.

Mechanic-Grade Diagnostic Values

• Fuel Injector Coil Resistance — expected: 1.74–2.04 ohms at 20°C (68°F). Failure: A reading of 0 ohms (short circuit) or OL/infinity (open circuit) on a multimeter.
• Injector Pulse Width (IPW) at idle — expected: 1-5 milliseconds (ms). Failure: A value of 0 ms for cylinder 1 while other cylinders show normal readings points to a circuit or PCM driver failure.
• Injector Harness - Short to Power Test — expected: 0 V. Failure: Any voltage reading indicates a short to power in the wiring harness between the injector and the PCM.
• Injector Harness - Short to Ground Test — expected: No continuity to body ground. Failure: Continuity indicates a short to ground in the wiring harness.

Hidden / Shadow Codes Worth Checking

• P0201:00: The ':00' suffix is a Failure Type Code (FTC) used by Mazda. It specifies the nature of the fault. In this case, it typically signifies that the PCM did not receive the expected injection verification signal, consistent with an open circuit. (see via This is typically visible on OEM dealer scan tools like Mazda IDS/MDARS or some high-end professional scanners.)

Scan Tool Commands That Help

• Mazda MDARS: PCM Reprogramming — This is a required step after installing a new PCM. The software downloads the correct calibration for the vehicle's VIN and programs the new module. Failure to do this will result in a no-start condition.
• FORScan / High-End Scanners: Injector Power Balance / Active Test — This bidirectional test allows a technician to individually disable each fuel injector while the engine is running. If disabling cylinder 1 causes no change in engine RPM, it confirms that cylinder was not contributing to begin with, validating the P0201 fault.
• Mazda IDS/MDARS: KOER Self Test (Key On, Engine Running) — Used after a repair (like fixing a wire or replacing an injector) to quickly verify that the fault does not immediately return under operating conditions.

Wiring & Ground Locations

• PCM Terminals 1DP and 1DO — At the main Powertrain Control Module connector.. These are the specific pins for the cylinder 1 fuel injector circuit on the Skyactiv-G engine. A technician must test for continuity, shorts to ground, or shorts to power between these pins and the corresponding pins at the fuel injector connector to definitively rule out a wiring fault.
• Main Engine/Transmission Grounds — Various points, including the top of the transmission case and from the passenger motor mount to the chassis.. While not directly part of the injector circuit, a poor or corroded main engine ground can create electrical noise and voltage drops that can confuse the PCM, potentially leading to false injector circuit codes.

Real Owner Repair Stories

• YouTube channel 'World Mechanics' (Not specified, but a vehicle with P0204 (same fault, different cylinder)) — Check Engine Light, rough running.
  ❌ Tried (didn't work) Initial diagnosis pointed towards a bad injector.
  ✅ What actually fixed it The metal spring clip on the fuel injector's electrical connector was missing or had lost tension, causing a poor connection. Replacing the clip and ensuring the connector was fully seated resolved the intermittent open circuit.

OEM Part Supersession History

• Various, e.g., PE22-18-881 → Later revisions, e.g., PE22-18-881A, etc. — Often to correct internal flaws (like the one causing the TSB issue) or improve performance/reliability.
  Heads up: It is critical to use the latest available part number for the specific vehicle VIN when replacing the PCM. Using an older or incorrect part number may re-introduce the original fault or cause other compatibility issues.

Model Year Variations Within This Range

• 2014 - May 23, 2016: Vehicles built before May 23, 2016, with Japan-built VINs lower than JM1GJ**484154 are susceptible to the DENSO PCM failure described in TSB 01-004/17. Vehicles built after this date have PCMs where the internal failure has been eliminated.

Diagnostic Flowchart

Other Known Issues on This Vehicle

Issues unrelated to this code that are worth knowing about as an owner of this generation:

• Infotainment Screen Delamination ('Ghost Touch') and Cracking 🟠 Medium — Widespread issue across many Mazda models of this era. Often occurs due to heat and thermal stress. (Ref: Multiple service alerts (e.g., SA-001/23a, SA-027-24) instruct dealers to use a screen repair kit instead of replacing the entire unit.)
• Intake Valve Carbon Buildup 🟡 Low — A common characteristic of all Gasoline Direct Injection (GDI) engines, including the Skyactiv-G. Mazda's design mitigates it, but it can still cause misfires or rough idle at higher mileage (over 100k miles).
• Failing Rear Brake Calipers 🟠 Medium — A noted common problem where calipers may seize or fail, leading to premature brake wear.
• Rattling Front Door Speakers 🟡 Low — Affects vehicles produced before December 12, 2015. Caused by corrosion on the speaker frame. (Ref: TSB 09-012/17)
• Failing Wheel Bearings 🟠 Medium — A frequently reported issue leading to a growling or whining noise that increases with vehicle speed. (Ref: Service Alert SA-006-22)

Used vs. New Parts: Buying Guide for This Vehicle

When a used part is the smart pick: A used fuel injector from a low-mileage donor vehicle can be a cost-effective repair if the original injector is confirmed to be electrically faulty (open or shorted). A used wiring harness pigtail is also a viable option if only the connector is damaged.

Donor-vehicle mileage cap: roughly under 80000 miles for the part to have meaningful remaining life.

What to inspect on the donor part:

• For injectors, check that the electrical pins are clean and straight.
• For wiring, ensure the connector's locking tab is intact and the wires are not brittle or cracked.
• Avoid parts from vehicles with signs of major engine fire, flood, or front-end collision damage.

OEM-only on this vehicle (don't cheap out):

• Powertrain Control Module (PCM)

Aftermarket brands forum-validated for this vehicle:

• Bosch
• Hitachi

Brands owners have reported issues with on this vehicle:

• No-name, unbranded injectors from online marketplaces are a significant gamble and often have poor quality control.

Real Owner Stories

Aggregated from forums and TSBs cited above. Mileages and costs reflect what owners reported in those sources.

Related OBD-II Codes

• P0204 — Often appears simultaneously with P0201 on this vehicle due to a shared failure of the internal driver circuit in DENSO-produced PCMs.
• P0202 — Another injector circuit code mentioned in TSB 01-004/17; it may appear paired with P0203 if the PCM driver fails for those specific cylinders.
• P0203 — Paired companion code to P0202, identifying the same internal PCM failure mode described in the vehicle-specific TSB.
• P0301 — A cylinder 1 misfire code that frequently accompanies P0201 because the engine cannot properly combust fuel when the injector circuit is open or shorted.
• P0304 — A misfire code that may appear if the P0201/P0204 PCM failure occurs, or due to related issues like a faulty Air-Fuel Ratio sensor.

Frequently Asked Questions