P0206 on 2014-2020 Ram 3500: Injector 6 Circuit/Open Causes & Fixes

What's Unique About the 2014-2020 Ram 3500

For the Ram 3500, particularly with the 6.7L Cummins engine, the injector wiring harness is a known weak point. It is integrated into the valve cover gasket and subjected to intense heat, oil, and vibration, which can cause wires to become brittle and break over time. Ram also issued several Technical Service Bulletins (TSBs), including #18-028-16 REV. A and #18-045-15 REV A, to change the fault logic for this code from a sensitive one-trip fault to a more robust two-trip fault. This was done to reduce false Check Engine Lights from momentary connection glitches that are common with the harness design.

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) Ram Heavy Duty trucks. While the P0206 code's meaning is the same, 2019-2020 models with the 6.7L Cummins used a Bosch CP4 high-pressure fuel pump that was subject to a major safety recall (Y78 / NHTSA 21V-880). A catastrophic failure of this pump can send metal debris throughout the fuel system, destroying the injectors and causing a P0206 code as a secondary, and very expensive, symptom. The injectors themselves were also redesigned for 2019+ models to operate at higher pressures.

Symptoms You May Notice

• Check Engine Light is on
• Rough idle and engine vibration
• Noticeable loss of engine power and acceleration
• Engine misfire or stumble
• Engine may not start
• Vehicle may enter 'limp mode' with restricted speed
• Abnormal engine noise

Most Likely Causes

1. Failed #6 Fuel Injector 🔴 High Probability High-pressure common rail injectors on the 6.7L Cummins are a known wear item. The internal solenoid coil can fail from heat cycles and high mileage, creating an open circuit. On the 6.4L Hemi, the injector can also fail internally but it is less common.
   How to confirm: Measure the resistance across the two terminals of the injector with a multimeter. For a 6.7L Cummins, the reading should be very low, between 0 and 1 ohm. For a 6.4L Hemi, it should be around 12-16 ohms. An infinite reading (OL) means the injector coil is open. The most definitive test is to swap the #6 injector with an adjacent one (like #5), clear the codes, and see if the fault moves to P0205.
   Typical fix: Replace the faulty fuel injector. It is also highly recommended to replace the high-pressure connector tube (Cummins) and sealing washer at the same time to prevent leaks.
   Est. part cost: $300-$700
2. Injector Wiring Harness Issue 🔴 High Probability On 6.7L Cummins engines, the injector harness is located under the valve cover, where constant exposure to heat and vibration can make wires brittle and cause them to break. The main pass-through connector on the valve cover is also a common point of failure.
   How to confirm: Visually inspect the wiring harness leading to injector #6 for any signs of chafing, melting, or breaks. Perform a 'wiggle test' on the harness connectors while the engine is running to see if it affects the idle. Use a multimeter to check for continuity on the power and ground wires between the PCM and the injector connector.
   Typical fix: Repair the damaged section of the wire. If the connector pigtail is damaged, it can be replaced. In many cases, the entire under-valve-cover harness (often part of the valve cover gasket assembly) must be replaced.
   Est. part cost: $80-$260
3. Loose or Corroded Injector Terminal Nuts 🟡 Medium Probability
   How to confirm: On the 6.7L Cummins, remove the valve cover and inspect the two small nuts that secure the wiring to the top of the #6 injector. Check if they are loose or show signs of corrosion.
   Typical fix: Clean the terminals and tighten the nuts to the correct, very low torque specification of 11-13 in-lbs (1.2-1.5 Nm). Do not overtighten, as this can easily damage the injector solenoid post.
   Est. part cost: $0

Rare But Worth Checking

• Faulty Powertrain Control Module (PCM): This is a rare cause. The internal driver circuit for injector #6 within the PCM can fail. This should only be considered after all wiring and the injector itself have been tested and confirmed to be good. Often, if the PCM is the cause, multiple injector codes for the same bank (e.g., P0204, P0205, P0206) will appear together.

Diagnosis Steps

1. Read all diagnostic trouble codes with an OBD-II scanner. Note if other injector or misfire codes are present, especially for bank 2 (P0204, P0205, P2149).
2. Visually inspect the main engine wiring harness and the connector at the valve cover for damage or corrosion.
3. For 6.7L Cummins, remove the valve cover. Check that the terminal nuts on top of injector #6 are tight (11-13 in-lbs).
4. Use a noid light. Disconnect the #6 injector harness and plug in the noid light. Start the engine. If the light flashes steadily, the PCM and wiring are sending a signal, pointing towards a bad injector. If it does not flash, the problem is in the wiring or PCM.
5. If the noid light test fails, check for a signal at the main pass-through connector on the valve cover to isolate if the fault is inside or outside the engine.
6. Disconnect the wiring from injector #6 and measure its resistance with a multimeter. A 6.7L Cummins injector should measure less than 1 ohm. A 6.4L Hemi injector should be ~12-16 ohms. An infinite (OL) reading indicates a failed injector.
7. If injector resistance is good, perform a continuity test on the power and ground wires for injector #6 between the main harness connector and the injector itself to find any breaks in the under-valve-cover harness.
8. For a definitive diagnosis, swap the #6 injector with the #5 injector. Reassemble, clear the codes, and run the engine. If the code returns as P0205, the injector is faulty. If P0206 returns, the problem is in the wiring or PCM.
9. If all wiring and the injector test good, the PCM is the last remaining possibility.

Parts You'll Likely Need

• Fuel Injector (6.7L Cummins) (OEM #68210105AA (2013-2018), 68444790AA (2019-2020)) — This is the most common component to fail internally, causing an open circuit.
  Trusted brands: Bosch, Mopar, Cummins
  OEM price range: $400-$700
  Aftermarket price range: $300-$500
• Injector Wiring Harness / Valve Cover Gasket (6.7L Cummins) (OEM #Mopar: 5179091AD, Cummins: 5367847) — The under-valve-cover harness is a frequent failure point due to heat and vibration. It is sold as an assembly with the valve cover gasket.
  Trusted brands: Mopar, Cummins, Dorman, AVP
  OEM price range: $250-$300
  Aftermarket price range: $80-$150
• High-Pressure Fuel Connector Tube (6.7L Cummins) (OEM #Mopar: 68460261AA, Bosch: F00RC00647) — This tube connects the fuel rail to the injector. It is a single-use-seal component and should be replaced any time an injector is replaced to prevent high-pressure fuel leaks.
  Trusted brands: Bosch, Mopar, Exergy
  OEM price range: $50-$80
  Aftermarket price range: $30-$60
• Fuel Injector (6.4L Hemi) (OEM #4627479AB) — Less common than on the Cummins, but the injector can still fail, causing an open circuit.
  Trusted brands: Mopar, Bosch
  OEM price range: $80-$150
  Aftermarket price range: $50-$100

Related Codes That Often Appear With This One

• P0306 — This code means 'Cylinder 6 Misfire Detected.' Since P0206 indicates an electrical problem stopping fuel delivery to cylinder 6, a misfire is the direct mechanical result.
• P2149 — This code stands for 'Fuel Injector Group 'B' Supply Voltage Circuit/Open.' On the 6.7L Cummins, injectors 4, 5, and 6 are grouped in Bank 2. A significant wiring issue or PCM driver fault affecting cylinder 6 can sometimes trigger a fault for the entire group.
• P0087 — This code means 'Fuel Rail/System Pressure - Too Low.' On 2019-2020 models, this code may appear alongside P0206 if the root cause is a failing CP4 high-pressure fuel pump that is starting to break apart and can no longer maintain rail pressure.

Technical Service Bulletins (TSBs) & Recalls

• 18-099-22 REV. A: Links P0206 to a no-start condition, superseded by recall Y78.
• 18-028-16 REV. A: Documents change from one-trip to two-trip fault for P0206.
• 18-045-15 REV A: Also documents change from one-trip to two-trip fault for P0206.
• 18-099-22: Original TSB for P0206 and no-start condition.
• 18-028-16: Original TSB for one-trip to two-trip fault change.

Platform-Specific Known Issues

• Recall Y78 / NHTSA 21V-880: Affects 2019-2020 models with the 6.7L Cummins. The Bosch CP4.2 high-pressure fuel pump is prone to catastrophic failure, which sends metal debris through the entire fuel system. This can destroy all six injectors, potentially causing a P0206 code as a result of the debris damage.

Mechanic-Grade Diagnostic Values

• 6.7L Cummins Fuel Injector Resistance — expected: Between 0 and 1 Ohm. Failure: A reading of infinity (Open Loop) or significantly greater than 1 Ohm indicates a failed injector coil.
• 6.7L Cummins Injector Harness Continuity — expected: Less than 10 Ohms. Failure: Resistance greater than 10 Ohms indicates an open or high resistance in the wiring between the PCM and the injector.
• 6.7L Cummins Injector Circuit Short to Ground — expected: Greater than 100k Ohms. Failure: Resistance less than 100k Ohms between either the high or low side driver circuit and chassis ground indicates a short.
• 6.7L Cummins Injector Pulse Width (Scan Tool) — expected: 0.5 - 0.9 ms at hot idle. Failure: A value of zero, or a value significantly different from the other cylinders, indicates a control or injector problem.
• Injector Circuit Voltage (Key On, Engine Off) — expected: Approximately 12V (Battery Voltage) on the high-side driver wire. Failure: Low or no voltage points to a problem in the power supply circuit upstream of the injector.

Scan Tool Commands That Help

• wiTECH (or equivalent professional scan tool): Cylinder Cutout / Injector Kill Test — This is a crucial bidirectional test to confirm if cylinder 6 is contributing to engine operation. The tool commands the PCM to stop firing the #6 injector. If there is no change in engine idle speed or smoothness, it confirms the cylinder was already dead, which is expected with an active P0206.

Wiring & Ground Locations

• Cylinder 6 Injector Circuits (at PCM C1 Connector) — The PCM is located on the driver's side of the engine block. C1 is one of the large multi-pin connectors.. These are the origin points for the injector control signals. For cylinder 6, the specific circuits are K658 (High Side Driver) and K58 (Low Side Driver). Testing for continuity or shorts should start from these pins to the valve cover pass-through connector.
• Valve Cover Pass-Through Harness Connector — The large, circular electrical connector mounted on the valve cover.. This is the junction between the main engine harness and the under-valve-cover harness. It's a common point for corrosion or pin damage and is a key location for isolating whether a wiring fault is internal or external to the engine.
• G104 / G105 Engine Grounds — G104 is in the left front of the engine compartment; G105 is the ground cable on the right side of the engine block.. While not specific to the injector circuit, a poor engine or chassis ground can cause a host of intermittent and difficult-to-diagnose electrical issues, including faults that could be misinterpreted by the PCM. Ensuring these are clean and tight is a fundamental step.

Real Owner Repair Stories

• Dodge Diesel - Ram Truck Forum user (2007 Ram 6.7L Cummins) — Intermittent Check Engine Light with code P0206.
  ❌ Tried (didn't work) Testing the injector solenoid (showed good resistance), Checking for continuity to ground (showed no short)
  ✅ What actually fixed it The problem was intermittent and not easily reproducible. The final fix was replacing the entire valve cover gasket, which includes the integrated injector wiring harness. The user noted that a short in any injector circuit on Bank 2 (cylinders 4, 5, 6) can cause the ECM to shut down all three injectors to protect the driver circuit.

OEM Part Supersession History

• 68210105AA (Mopar) → R8210105AA (Mopar Remanufactured) — This part is typically sold as a remanufactured unit. The 'R' prefix on the Mopar part number indicates it is a remanufactured component.
  Heads up: This part number is for 2013-2018 Ram 6.7L Cummins engines. It is not compatible with 2019+ models, which use a different injector design.
• 0445120342 (Bosch) → 0986435621 (Bosch Remanufactured) — Bosch is the original equipment manufacturer. 0986435621 is the Bosch part number for their factory remanufactured injector, which corresponds to Mopar PN 68210105AA.

Model Year Variations Within This Range

• 2019-2020: The 6.7L Cummins engine was significantly updated. The fuel injectors are a different design, operating at a higher pressure of 200 MPa (vs. 180 MPa on earlier models) and have different internal components and nozzle nuts. They use a different part number (e.g., 68444790AA for High Output models) and are not interchangeable with the 2014-2018 injectors.
• 2014-2018: These models use the earlier style piezo injector (PN 68210105AA). Several TSBs were released for these model years to update the PCM software, making the P0201-P0206 fault logic a 'two-trip' fault to reduce false positives from momentary connection issues.