P0203 on 2011-2023 Chrysler 300 3.6L: Injector Circuit Malfunction Causes and Fixes

What's Unique About the 2011-2023 Chrysler 300

On the 3.6L Pentastar V6 engine used across the Chrysler, Dodge, and Jeep lineup, P0203 is a very common and well-documented problem. The failure rate for the fuel injectors themselves is high, often making it the primary suspect over more complex wiring issues. Cylinder #3 is located on the passenger-side cylinder bank (the middle cylinder), and accessing it requires removing the upper intake manifold, making the job more involved than on some other engines. Because of the labor required to access the injectors, many mechanics and owners recommend replacing all three injectors on the passenger-side bank (cylinders 1, 3, 5) at the same time.

Symptoms You May Notice

• Check Engine Light is on (may be flashing in severe cases)
• Rough or shaky idle
• Engine misfires, often felt as a shudder or hesitation
• Noticeable loss of power and poor acceleration
• Reduced fuel economy
• Engine may stall at low speeds

Most Likely Causes

1. Failed Cylinder 3 Fuel Injector 🔴 High Probability The fuel injectors on the 3.6L Pentastar are a known, widespread failure point. The internal electronic coil windings can fail from repeated heat cycles and vibration, creating an open circuit. This is the most common cause for P0203 by a wide margin. Some technicians theorize the solder joint where the terminal meets the internal windings is a common point of failure.
   How to confirm: Test the injector's resistance with a multimeter; a healthy injector should read approximately 12-14 Ohms. An 'OL' (Open Line) or infinite reading indicates failure. A reading that is significantly different, such as double the normal resistance (~24 Ohms), has also been observed in failed injectors. The most definitive test is to swap the #3 injector with another cylinder on the same bank (e.g., #1 or #5). Clear the codes and see if the fault moves to the new cylinder 🎬 Watch: A guide to testing Pentastar fuel injectors for codes P0201-P0206. (e.g., P0201 or P0205). If it does, the injector is bad.
   Typical fix: Replace the failed fuel injector. It is strongly recommended to replace all three injectors on the passenger-side bank at the same time, as the others may be near the end of their service life. Always replace the upper intake manifold gaskets during this job.
   Est. part cost: $45-$155
2. Wiring Harness or Connector Issue 🟡 Medium Probability The engine harness is exposed to significant heat and vibration, which can lead to brittle wires, chafed insulation, or loose/corroded pins in the connector over time. The plastic locking tab on the connector can also become brittle and break.
   How to confirm: Visually inspect the wiring harness leading to the #3 injector for any signs of melting, chafing, or breaks. Check the electrical connector for corrosion, backed-out pins, or a loose fit. Use a noid light to confirm if a pulse signal is being sent from the PCM; a flashing light means the wiring and PCM are likely good. If no pulse is present, check for 12V power on the power feed wire (often Dark Green/Orange) with the key on.
   Typical fix: Repair the damaged section of the wiring harness or replace the injector connector pigtail.
   Est. part cost: $15-$50

Rare But Worth Checking

• Faulty Powertrain Control Module (PCM): This is the least likely cause. The internal driver circuit for the injector can fail. This should only be considered after the injector and wiring have been thoroughly tested and ruled out.

Diagnosis Steps

1. Connect an OBD-II scanner and confirm that P0203 is present. Note any other codes, such as P0303, which is expected.
2. Locate cylinder #3, which is the middle cylinder on the passenger (right) side of the engine.
3. Visually inspect the wiring harness and electrical connector for cylinder #3. Look for any obvious signs of damage, melting, or corrosion.
4. Disconnect the fuel injector and test its internal resistance using a multimeter set to Ohms. 🎬 See how to check fuel injector resistance with a multimeter. A good injector should measure between 12 and 14 Ohms. A reading of infinity (OL) indicates an open circuit and a failed injector.
5. To definitively confirm a bad injector, swap the cylinder #3 injector with an adjacent one on the same bank (like cylinder #1 or #5). This requires removing the upper intake manifold. Clear the codes, run the engine, and rescan. If the code changes to P0201 or P0205, the injector is confirmed to be faulty.
6. If the P0203 code returns after the swap, the problem lies in the wiring or the PCM. Use a 'noid light' on the cylinder #3 connector to see if the PCM is sending a flashing pulse signal while the engine is running. A steady flashing light indicates the PCM and wiring are sending the signal correctly. No light or a steady-on light points to a wiring or PCM issue.
7. If the noid light test fails, check for 12V on the power supply wire at the connector with the key on. If power is present, check the control wire for continuity back to the PCM to rule out a break in the harness.
8. If the wiring and injector are confirmed good, the fault likely lies with the PCM's injector driver circuit, and the PCM may need to be repaired or replaced.

Parts You'll Likely Need

• Fuel Injector (OEM #5184085AD (supersedes 5184085AC)) — This is the most common failure point for a P0203 code on the 3.6L Pentastar engine due to internal coil failure.
  Trusted brands: Mopar, Bosch (OEM supplier, P/N 0280158233), Standard Motor Products
  OEM price range: $70-$155
  Aftermarket price range: $45-$75
• Upper Intake Manifold Gasket Set (OEM #5184331AC) — The upper intake manifold must be removed to access the fuel injectors on the 3.6L V6. The gaskets are single-use and must be replaced to prevent vacuum leaks after the repair.
  Trusted brands: Mopar, Fel-Pro, Mahle
  OEM price range: $20-$40
  Aftermarket price range: $15-$30

Related Codes That Often Appear With This One

• P0303 — P0303 means 'Cylinder 3 Misfire Detected.' Since P0203 indicates a fault preventing fuel delivery to cylinder 3, the cylinder cannot combust properly, which directly causes a misfire. P0203 is the cause, and P0303 is the effect.

Technical Service Bulletins (TSBs) & Recalls

• TSB 14-003-22 REV. A: While specific to 2022 models, this TSB acknowledges that fuel injector issues are a known area of concern for the manufacturer, lending credibility to injector failure as a root cause for injector circuit codes.

Platform-Specific Known Issues

• Real-world owner experience strongly suggests that if one injector fails on a higher-mileage Pentastar, others are likely to fail soon. Due to the 2-3 hours of labor required to remove the upper intake manifold, it is highly advisable to replace all three injectors on the passenger bank (1, 3, 5) at the same time to avoid repeat repairs.
🎬 Watch: How to diagnose and replace a Chrysler 300 fuel injector.

Mechanic-Grade Diagnostic Values

• Fuel Injector Coil Resistance — expected: 12.0 - 14.0 Ohms at room temperature. A common reading is ~12.5 Ohms.. Failure: A reading of 'OL' (infinite resistance), near 0 Ohms (shorted), or a reading double the normal resistance (~24 Ohms) indicates a failed injector.
• Injector Control Circuit Continuity (PCM to Injector) — expected: Below 5.0 Ohms. Failure: Resistance above 5.0 Ohms indicates excessive resistance or an open in the control wire.
• Injector Power Supply Wire Voltage — expected: Battery Voltage (approx. 12.6V) with Key On, Engine Off.. Failure: 0V indicates a problem with the power supply from the Auto Shutdown (ASD) relay, its fuse, or the TIPM.
• Injector Control Circuit to Ground — expected: Infinite resistance (OL). Failure: Any reading less than infinite indicates a short to ground in the control wire between the PCM and the injector.

Scan Tool Commands That Help

• wiTECH (Chrysler Dealer Tool) or equivalent high-end scanner: Injector Kill Test / Actuator Test — This bidirectional command allows the technician to individually disable the cylinder 3 injector while the engine is running. If disabling the injector causes no change in engine RPM or smoothness, it confirms that cylinder 3 was not contributing, which is expected with a P0203. This helps verify the misfire is isolated to that cylinder before physical disassembly.

Wiring & Ground Locations

• Cylinder 3 Injector Connector — On the fuel rail, middle injector on the passenger (right) side bank, under the upper intake manifold.. This is the primary connection point for testing. It is a USCAR (EV6) style connector. Pin 1 is the control wire (pulsed ground from PCM), and Pin 2 is the power supply (12V+ from ASD relay).
• Auto Shutdown (ASD) Relay — Located in the underhood Power Distribution Center / fuse box (also known as the TIPM).. This relay supplies battery voltage to all six fuel injectors. While a total failure would affect all cylinders, an intermittent or high-resistance fault within the TIPM could theoretically affect a single injector circuit.
• PCM Connectors — The Powertrain Control Module (PCM) is typically located in the engine bay, often near the firewall or inner fender.. The control wire for the cylinder 3 injector runs from the injector connector to a specific pin on one of the main PCM connectors (often C1). A continuity test between these two points is the definitive way to rule out a wiring break.

Real Owner Repair Stories

• Chrysler Forum thread (2006 Chrysler Town & Country 3.6L (related platform)) — Persistent P0203 'Cylinder 3 Injector Circuit Open' code.
  ❌ Tried (didn't work) Replaced the fuel injector for cylinder 3., Replaced the wiring harness to the injector.
  ✅ What actually fixed it The problem was ultimately resolved by replacing the Powertrain Control Module (PCM/ECU), indicating a failed internal injector driver.
• NHTSA ODI #11539650 (Chrysler Pacifica with 3.6L engine) — An owner reported that the vehicle began shaking and the check engine light illuminated. A scan revealed codes P0420, P0303, and P0203, noting that many other owners of the same platform had experienced the same issue.

OEM Part Supersession History

• 5184085AC → 5184085AD — Standard part revision, likely for improved reliability or manufacturing process.
  Heads up: The parts are fully interchangeable. The OEM supplier is Bosch, and their equivalent part number is 0280158233.

Model Year Variations Within This Range

• 2016-2023: Starting in 2016, the 3.6L Pentastar was upgraded (sometimes called 'Pentastar UPG'). While the fundamental injector design and failure mode for P0203 remain the same, the upper intake manifold is more complex due to the addition of an EGR cooler and longer intake runners. This can make the labor to access the injectors slightly more time-consuming compared to the 2011-2015 models.

Diagnostic Flowchart

Other Known Issues on This Vehicle

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

• Cracked Oil Filter Housing & Cooler Assembly 🔴 High — Extremely common across all model years. The plastic housing becomes brittle from heat cycles and cracks, causing significant oil and/or coolant leaks. (Ref: No recall has been issued, despite widespread failure. Aftermarket aluminum housings are a popular and recommended upgrade.)
• Rocker Arm Bearing Failure ('Pentastar Tick') 🔴 High — Common across many model years, often appearing after 60,000 miles. Needle bearings in the rocker arms fail, causing a distinct ticking sound, metal debris in the oil, and eventual camshaft damage if ignored. (Ref: No specific recall, but the subject of class-action lawsuits.)
• Left Cylinder Head Defect 🔴 High — Specific to early 2011-2013 models. A manufacturing defect caused premature wear of valve guides/seats on the left bank (cylinders 2, 4, 6), leading to misfires (P0302, P0304, P0306) and requiring head replacement. (Ref: TSB 09-002-14 Rev. B; Chrysler issued an extended warranty (X56) for 10 years/150,000 miles, which has now expired for most vehicles.)

Used vs. New Parts: Buying Guide for This Vehicle

When a used part is the smart pick: For this repair, using a used fuel injector from a junkyard is NOT recommended. The failure rate of these injectors is high due to internal electrical faults from heat and vibration. A used injector has unknown remaining life and carries a high risk of failing shortly after installation, forcing you to repeat the significant labor of removing the intake manifold.

What to inspect on the donor part:

• Not applicable as used injectors are not advised for this repair.

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

• While not strictly 'OEM-only', using a new, quality part is critical. A new OEM Mopar or OEM-supplier (Bosch) injector is the safest choice. Avoid used injectors entirely.

Aftermarket brands forum-validated for this vehicle:

• Bosch (P/N 0280158233) is the OEM supplier and is considered a top-tier replacement.
• Standard Motor Products (SMP)

Brands owners have reported issues with on this vehicle:

• Unnamed, low-cost injector sets from online marketplaces are a significant gamble. Given the labor involved, the risk of premature failure with a no-name brand often outweighs the initial cost savings.

Real Owner Stories

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

Related OBD-II Codes

• P0303 — Cylinder 3 Misfire Detected; this is the most common companion code to P0203 because the injector circuit failure prevents fuel delivery, causing an immediate misfire.
• P0201 — Injector Circuit - Cylinder 1; often appears if the fault moves after swapping the #3 injector to cylinder #1 during diagnostic testing.
• P0205 — Injector Circuit - Cylinder 5; often appears if the fault moves after swapping the #3 injector to cylinder #5 during diagnostic testing.
• P0302 — Cylinder 2 Misfire; related to the known left cylinder head defect on 2011-2013 models (TSB 09-002-14 Rev. B).
• P0304 — Cylinder 4 Misfire; related to the known left cylinder head defect on 2011-2013 models (TSB 09-002-14 Rev. B).
• P0306 — Cylinder 6 Misfire; related to the known left cylinder head defect on 2011-2013 models (TSB 09-002-14 Rev. B).

Frequently Asked Questions