P0201 on 2014-2020 Ram 3500 6.7L Cummins: Injector Circuit/Open Causes and Fixes

What's Unique About the 2014-2020 Ram 3500

For the 2014-2020 Ram 3500 with the 6.7L Cummins, the P0201 code is often linked to two platform-specific issues. First, the wiring harness that passes under the valve cover to the injectors is a well-documented weak point; heat, oil saturation, and vibration often cause the wiring to become brittle and fail, creating an open circuit. Second, on 2019-2020 models equipped with the Bosch CP4.2 high-pressure fuel pump, a P0201 code (often with other injector and low-pressure codes like P0087) can be an early sign of catastrophic pump failure. This specific issue prompted a major safety recall. Additionally, a manufacturer TSB changed this from a one-trip to a two-trip fault to reduce nuisance codes. [Bulletin #18-028-16 REV. A]

Diagnostic Flowchart

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

Generation note: This range covers the end of the Fourth Generation (2014-2018) and the start of the Fifth Generation (2019-2020). While the causes are similar, 2019-2020 models with the Bosch CP4.2 high-pressure fuel pump have a specific, critical issue where pump failure can trigger P0201 and other codes, as noted in TSB #18-099-22 REV. A and recall Y78.

Symptoms You May Notice

• Check Engine Light is on
• Rough idle or engine stumble
• Loss of power and acceleration
• Engine misfire
• Poor fuel economy
• White or black smoke from exhaust due to incomplete combustion

Most Likely Causes

1. Faulty Cylinder 1 Fuel Injector 🔴 High Probability → Shop Fuel Injector The high-pressure common rail injectors operate under immense stress (over 29,000 PSI) and can fail electrically over time. The internal solenoid coil can burn out or short, causing an open or out-of-spec resistance reading.
   How to confirm: Measure the resistance across the two terminals of the injector with a multimeter. It should be very low, between 0 and 1.0 Ohm. An 'OL' or infinite reading indicates a failed open coil, while 0 ohms indicates a short. Also, test from each terminal to the injector body; the reading should be infinite (OL), as any continuity indicates a short to ground. The most definitive test is to swap the #1 injector with another cylinder (e.g., #2). If the code changes to P0202, the injector is bad.
   Typical fix: Replace the failed fuel injector. It is highly recommended to also replace the high-pressure connector tube to prevent leaks. The new injector's 6-digit IQA code must be programmed into the PCM using a capable scan tool. Torque for injector solenoid nuts is critical and very low, around 13 in-lbs (1.5 Nm).
   Est. part cost: $450-$850
2. Damaged Injector Wiring Harness (Under Valve Cover) 🔴 High Probability → Shop Engine Wiring Harness The wiring harness under the valve cover is constantly exposed to extreme heat cycles, engine vibration, and oil, causing wires to become brittle, break, or chafe against the rocker housing. This is a very common point of failure.
   How to confirm: After removing the valve cover, visually inspect the harness for broken, brittle, or chafed wires, especially near the #1 injector connector. Test for continuity on both wires from the injector connector back to the main pass-through connector. A 'wiggle test' on the harness while checking continuity can help identify intermittent breaks.
   Typical fix: Replace the injector wiring harness. This requires removing the valve cover for access. It is often recommended to replace the harness as a preventative measure when replacing injectors. Torque the injector terminal nuts to 8.8-13 in-lbs upon reassembly.
   Est. part cost: $50-$150

Rare But Worth Checking

• Failed High-Pressure Fuel Pump (HPFP): On 2019-2020 models with the CP4.2 pump, this is a critical check. If P0201 appears with other injector codes (P0202-P0206) and fuel pressure codes like P0087, it may indicate pump failure sending metal debris through the system. This is covered by FCA recall Y78 / NHTSA 21V880 and requires replacement of the entire fuel system.
• Shorted Injector Solenoid (Bank Shutdown): → Shop Fuel Injector A short circuit within the #1 injector can cause the PCM's internal driver to shut down the entire bank (cylinders 1-3) to protect itself. This will result in codes P0201, P0202, P0203, and often P2146 appearing simultaneously. This points to a single component failure causing a group-wide fault.
• Blown Fuel Injector Fuse: → Shop Fuel Injector A short circuit in one of the injector circuits can blow the shared fuse for the injector bank (Cylinders 1-3). Before extensive diagnosis, check the 25A injector fuse in the under-hood fuse box.
• Faulty Powertrain Control Module (PCM): → Shop Engine Control Module (ECM) This is very rare and should only be considered after all other possibilities (injector, wiring, connectors) have been exhaustively ruled out with multimeter tests.

Diagnosis Steps

1. Read codes with an OBD-II scanner and confirm P0201 is active. Note any other codes present, especially P0202, P0203, P2146, or P0087.
2. On 2019-2020 models with P0087, immediately inspect the fuel filter for metallic 'glitter'. If found, STOP and assume CP4 pump failure to avoid further system damage.
3. Inspect the external wiring harness leading to the valve cover for obvious damage, chafing, or melting.
4. For a definitive injector test, swap the #1 fuel injector with the #2 injector. Clear codes and run the engine. If the code changes to P0202, the injector is faulty. If P0201 returns, the problem is in the wiring.
5. If wiring is suspected, disconnect the battery and remove the valve cover.
6. Carefully inspect the internal injector wiring harness for broken, brittle, or chafed wires, especially near the #1 injector connector.
7. Use a multimeter to test for continuity on both wires from the injector #1 connector back to the main pass-through connector on the valve cover. Resistance should be < 1.0 Ohm.
8. Test for a short to ground by measuring resistance from each pin at the injector connector to a clean chassis ground. The reading should be infinite (OL). A low resistance reading indicates a short.
9. If the internal harness and injector are good, check the external harness from the pass-through connector back to the PCM for shorts or opens.
10. If all wiring and the injector are confirmed good, the issue may be a faulty PCM, but this is extremely rare and requires professional diagnosis.

Parts You'll Likely Need

• Fuel Injector (OEM #68210512AA (2014-2018), 68444790AA (2019-2020 HO), 68444791AA (2019-2020 SO)) — This is the most common point of failure for an isolated P0201 code if the wiring is intact.
  Trusted brands: Bosch (OEM supplier), Mopar, BD Diesel
  OEM price range: $600-$850
  Aftermarket price range: $450-$650
• Injector Wiring Harness (Internal) (OEM #4936385 (superseded by 5304332)) — The internal harness is a known weak point that becomes brittle from heat and vibration, causing open circuits. This is a very common cause for P0201, especially when seen with other codes in the same bank.
  Trusted brands: Mopar, Cummins
  OEM price range: $100-$150
  Aftermarket price range: $50-$90
• High-Pressure Connector Tube (OEM #5086874AB) — This is considered a single-use part that connects the fuel rail line to the injector. It should be replaced anytime an injector is replaced to prevent high-pressure fuel leaks. Failure to replace it can void the warranty on a new injector.
  Trusted brands: Mopar, Bosch, Fleece Performance
  OEM price range: $40-$60
  Aftermarket price range: $25-$40

Related Codes That Often Appear With This One

• P0301 — A fault in the injector circuit for cylinder 1 will prevent proper fuel delivery, directly causing a misfire in that cylinder.
• P0202, P0203 — On Cummins engines, injectors are grouped in banks (1-3 and 4-6). A short in one injector circuit can cause the PCM to shut down the entire bank to protect the driver, setting codes for all three injectors.
• P2146 — This code for 'Fuel Injector Group 'A' Supply Voltage Circuit/Open' frequently appears with P0201, P0202, and P0203, strongly suggesting a wiring harness issue or a single shorted injector rather than three separate injector problems.
• P0087 — As noted in TSB #18-099-22 REV. A, this 'Fuel Rail Pressure Too Low' code can appear with P0201 on 2019+ models, often indicating a failing high-pressure fuel pump sending metal debris through the system.

Technical Service Bulletins (TSBs) & Recalls

• 18-099-22 REV. A: Addresses multiple injector circuit codes (P0201-P0206) resulting from high-pressure fuel pump failure on 2019-2020 models.
• 18-028-16 REV. A: Changed P0201-P0206 from a one-trip to a two-trip fault.
• 18-099-22: Original TSB for fuel pump failure and resulting injector codes.
• 18-028-16: Original TSB for changing to a two-trip fault.
• 1805421: TSB for 2019 models also linking P0201 to fuel pump issues.

Platform-Specific Known Issues

• TSB #18-099-22 REV. A: Addresses multiple inj

Mechanic-Grade Diagnostic Values

• Fuel Injector Solenoid Resistance — expected: Less than 1.0 Ohm, but greater than 0 Ohms (after zeroing meter leads). Failure: Infinite resistance (OL) indicates an open coil. 0 Ohms indicates a shorted coil.
• Injector Circuit Resistance (at PCM connector) — expected: Between 0 and 1.0 Ohm for the complete circuit (High Side to Low Side driver pins).. Failure: A reading higher than 1.0 Ohm indicates high resistance in the wiring or connectors.
• Injector Circuit Short to Ground — expected: Greater than 10k Ohms.. Failure: A reading below 10k Ohms indicates a short to ground in the harness.
• Injector Solenoid Nut Torque — expected: 11-13 in-lbs (1.25-1.5 Nm).. Failure: Overtightening can break the injector solenoid post, causing immediate failure. Undertightening can lead to a poor connection.
• High-Pressure Connector Tube Nut Torque — expected: 37-41 ft-lbs (50-56 Nm).. Failure: Improper torque can lead to high-pressure fuel leaks at the injector body.
• Total Injector Return Flow (Running Test) — expected: Maximum of 210 mL in 30 seconds.. Failure: Flow greater than 210 mL indicates excessive leakage from one or more injectors.
• Total Injector Return Flow (Cranking Test) — expected: Maximum of 40 mL in 10 seconds.. Failure: Flow greater than 40 mL indicates a significant leak preventing the engine from starting.

Scan Tool Commands That Help

• wiTECH (Dealer Tool) or equivalent high-level scanner: Injector Kill Test / Cylinder Cutout Test — Used to isolate a misfiring or noisy cylinder. The scan tool commands the PCM to stop firing a specific injector. If killing cylinder #1 causes no change in engine idle or sound, it confirms that cylinder was not contributing, pointing to a fault in that circuit. If killing another cylinder makes the engine run worse, it confirms that cylinder was working properly.
• wiTECH or equivalent: Fuel Pressure Override Test — This function commands the fuel system to a specific high pressure (e.g., 26,107 PSI) at a set RPM (e.g., 1200 RPM) to perform a standardized injector return flow test. It allows for accurate measurement of injector leakage under controlled conditions.
• wiTECH or equivalent: Program IQA Codes — This is a required step after replacing a fuel injector. The 6-digit Injector Quantity Adjustment (IQA) code from the new injector must be programmed into the ECM to ensure accurate fueling and engine performance.

Wiring & Ground Locations

• PCM Connector C1 (Pins K11 & K611) — The Powertrain Control Module (PCM/ECM) is located on the driver's side of the engine block. C1 is one of the main harness connectors.. Pin K11 is the High Side Driver circuit and Pin K611 is the Low Side Driver circuit for fuel injector #1. Technicians test for continuity, shorts, and resistance between these pins and the injector connector to isolate a wiring fault from a component fault.
• Valve Cover Pass-Through Connector — A large, multi-pin connector on the driver's side of the valve cover where the main engine harness connects to the internal injector harness.. This is a critical diagnostic and failure point. The front connector serves injectors 1-3, while the rear serves 4-6. It is highly susceptible to oil contamination from the CCV system, which can degrade the connection and cause open circuits.
• Fuel Injector Fuse (e.g., F22) — Located in the under-hood Power Distribution Center (fuse box), usually near the driver's side battery.. A 25A fuse typically supplies power to the injector bank (cylinders 1-3). A short in any of the three injector circuits can blow this fuse, causing P0201, P0202, and P0203 to appear simultaneously.
• Main Engine Block Ground — A large ground cable connecting the negative battery terminal to the driver's side front of the engine block.. While a failure here would likely cause multiple, widespread electrical issues, a poor or corroded main ground is a foundational check for any electrical diagnosis, as it can cause unpredictable voltage drops and sensor errors.

Real Owner Repair Stories

• cumminsforum.com user (2014 Ram 3500) — Truck started running rough, check engine light came on with code P0201. Truck would sometimes run fine, then suddenly start missing.
  ❌ Tried (didn't work) Replaced the #1 fuel injector., Replaced the fuel rail pressure sensor., Swapped the #1 injector with the #2 injector; the code remained P0201.
  ✅ What actually fixed it The problem was ultimately traced to the engine wiring harness. A wire for the #1 injector circuit was intermittently shorting to ground where the harness had rubbed against a bracket. Repairing the chafed wire and protecting the harness resolved the issue permanently.

OEM Part Supersession History

• 4936385 → 5304332 — Improved design or material to better withstand heat and vibration under the valve cover.

Model Year Variations Within This Range

• 2019-2020: These models were equipped with the Bosch CP4.2 high-pressure fuel pump, which is prone to catastrophic failure. On these specific years, P0201 appearing with P0087 (Fuel Rail Pressure Too Low) and other injector codes is a strong indicator of HPFP failure, a problem not prevalent in the 2014-2018 models which used the more robust CP3 pump. This led to recall Y78.
• 2014-2015: Multiple Technical Service Bulletins (e.g., #18-028-16, #18-045-15) were issued for early 4th generation trucks to change the P0201-P0206 fault logic from a one-trip to a two-trip fault. This was a software update to reduce the frequency of the Check Engine Light illuminating for intermittent, non-critical connection issues, indicating it was a common nuisance code on earlier models in this range.