P0202 on 2007-2010 Dodge RAM 1500: Injector Circuit Malfunction Causes & Fixes

What's Unique About the 2007-2010 Dodge RAM 1500

For this generation of Dodge Ram, particularly with the 4.7L and 5.7L V8 engines, a P0202 code is often misdiagnosed. A widely-referenced manufacturer Technical Service Bulletin (TSB #9002688) specifically warns technicians to check the injector wiring loom and connector where it passes through or near the valve cover gasket before replacing any fuel injectors. This area is a known weak point prone to heat and vibration damage, causing an open or short in the circuit that mimics a failed injector. Forum discussions are filled with owners who replaced an injector only to find the true cause was a damaged wire.

Diagnostic Flowchart

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

Generation note: This year range covers the end of the third generation (2007-2008) and the beginning of the fourth generation (2009-2010) Ram 1500. While engine options (4.7L PowerTech, 5.7L HEMI) and specific part numbers vary, the underlying injector wiring design and the potential for harness failure are relevant to both generations within this period. The 5.7L HEMI was updated in 2009, which may affect specific part numbers for injectors and wiring.

Symptoms You May Notice

• Check Engine Light is on
• Rough idle or engine stumbling
• Engine misfire, which may feel like a shake or shudder
• Poor acceleration and loss of power
• Reduced fuel economy
• Engine may stall intermittently
• Strong smell of raw gasoline if the injector is stuck open

Most Likely Causes

1. Faulty Injector Wiring Harness or Connector 🔴 High Probability → Shop Engine Wiring Harness As noted in TSBs and confirmed by countless owner reports, the wiring loom is susceptible to damage from heat and vibration, especially where it is routed near the engine block, oil filter, or through the valve cover. The insulation becomes brittle, leading to chafed, broken, or shorted wires.
   How to confirm: Visually inspect the entire wiring harness for cylinder #2, from the PCM to the injector. Pay extremely close attention to the section near the valve cover and any contact points with the engine. Check for chafed, burnt, or broken wires. Perform a 'wiggle test' on the harness with the engine running to see if it affects the idle. Check for continuity from the PCM connector to the injector connector using a multimeter; resistance should be less than 5.0 ohms.
   Typical fix: Repair the broken wire by soldering and using heat-shrink tubing or replace the injector pigtail connector. In severe cases, a larger section of the engine wiring harness may need replacement.
   Est. part cost: $15-$50 for a pigtail connector; $200+ for a harness section.
2. Failed Fuel Injector 🟡 Medium Probability → Shop Fuel Injector Injectors can fail electrically over time due to internal coil windings breaking down.
   How to confirm: With a multimeter set to Ohms, measure the resistance across the two terminals of the #2 fuel injector. For the 5.7L HEMI, a good injector should read around 12-14.5 ohms. For the 4.7L, a good injector should read around 10.8-13.2 ohms. A reading that is significantly different (e.g., 17 ohms) or shows an open circuit (infinite resistance) indicates a failed injector. The most definitive test is to swap the #2 injector with another cylinder (e.g., #4), clear the codes, and see if the trouble code follows the injector (e.g., changes to P0204).
   Typical fix: Replace the fuel injector for cylinder #2. It is often recommended to replace all injectors as a set on higher mileage vehicles to ensure balanced fuel delivery.
   Est. part cost: $50-$150 per injector.
3. Blown Fuse ⚪ Low Probability
   How to confirm: Locate the fuse for the fuel injectors in the main fuse box under the hood (Totally Integrated Power Module). Visually inspect the fuse and test it with a multimeter. A video guide for 2013+ models shows a 25A fuse, but check your owner's manual for the specific fuse in your year.
   Typical fix: Replace the blown fuse. If the fuse blows again immediately, it confirms a short circuit in the injector wiring that must be found and repaired.
   Est. part cost: $1-$5

Rare But Worth Checking

• Faulty Powertrain Control Module (PCM): → Shop Engine Control Module (ECM) This is a rare cause and should only be considered after all wiring and the injector itself have been exhaustively tested and confirmed to be good. A failed injector driver transistor inside the PCM can cause this code. One owner on RamForum.com replaced the PCM, but the code remained, highlighting how rare this is as the root cause.
• Faulty Totally Integrated Power Module (TIPM): The TIPM is the main fuse and relay box that controls nearly all of the vehicle's electrical functions. For 2006-2009 Ram trucks, TIPM failures are a known issue, though they more commonly affect lighting systems. However, a fault within the TIPM, such as a failing internal relay for the ASD (Auto Shutdown) circuit which powers the injectors, can cause a P0202 code. This should be considered if the fuse is good but power is not being supplied to the injector circuit.

Diagnosis Steps

1. Scan for Codes: Use an OBD-II scanner to confirm P0202 is the active code and check for any other related codes, such as P0302 (Cylinder 2 Misfire).
2. Visual Inspection: Carefully inspect the wiring harness and connector for fuel injector #2. Pay extremely close attention to the wiring loom where it passes near or through the valve cover, and also check for damage near the oil filter area.
3. Check for Signal with a Noid Light: 🎬 See these 5 simple DIY methods to test your injectors. Disconnect the harness from the #2 injector and plug in a noid light. Start the engine. The light should flash steadily, indicating the PCM is sending a signal. If it doesn't flash, the problem is in the wiring or the PCM. If it flashes, the wiring to the injector is likely good.
4. Test the Injector Resistance: If the noid light flashes, the injector itself is suspect. Turn off the engine. Use a multimeter to measure the resistance of the injector. It should be within a specific range (10.8-13.2 ohms for 4.7L, ~12-14.5 ohms for 5.7L). Compare the reading to an adjacent injector; if it's very different or open, the injector has failed.
5. Check Wiring Continuity: If the noid light test fails, check for an open or short in the wiring. Disconnect the battery. Disconnect the injector connector and the corresponding PCM connector (C2). Use a multimeter to check for continuity on the control wire (Pin 2 on injector to appropriate pin on PCM connector). Resistance should be below 5.0 ohms. Also check the control wire for a short to ground.
6. Swap Components: As a definitive test, swap the #2 fuel injector with one from another cylinder (e.g., #4). Clear the codes and drive the vehicle. If the code changes to P0204, the injector is faulty. If the P0202 code returns, the problem is confirmed to be in the wiring or PCM.
7. PCM Check: If all wiring and the injector have been proven to be good through the above steps, the issue may be a faulty injector driver in the PCM, though this is the least likely cause.

Parts You'll Likely Need

• Fuel Injector Wiring Harness Pigtail (OEM #Mopar 5183448AA (example, verify fitment)) — This is a very likely fix, as the wiring near the connector often fails due to heat and vibration. Soldering in a new pigtail is a common repair.
  Trusted brands: Mopar, Dorman, ACDelco
  OEM price range: $40-$80
  Aftermarket price range: $15-$40
• Fuel Injector (OEM #5.7L HEMI (2009-10): 5037479AC, 5037479AA; 4.7L (2008-10): 53032701AA) — If the wiring is intact, the injector itself may have an internal electrical failure.
  Trusted brands: Bosch, Standard Motor Products (FJ732), Mopar
  OEM price range: $100-$180
  Aftermarket price range: $50-$100
• Valve Cover Gasket (OEM #RL002012A$ (from TSB)) — The TSB mentions this part. The valve cover may need to be removed to properly access and repair the injector wiring harness, and the gasket should be replaced at that time.
  Trusted brands: Fel-Pro, Mopar
  OEM price range: $40-$70
  Aftermarket price range: $20-$40

Related Codes That Often Appear With This One

• P0302 — P0302 means 'Cylinder 2 Misfire Detected.' Since the P0202 code indicates a problem with the fuel injector circuit for cylinder 2, that cylinder is not receiving the correct amount of fuel, which directly causes a misfire.

Technical Service Bulletins (TSBs) & Recalls

• Bulletin #9002688: Advises checking the wiring loom and/or connector in the valve cover gasket before replacing injectors for Diagnostic Trouble Codes P0201, P0202, P0203, P0204, P0205, and/or P0206.

Platform-Specific Known Issues

• A known issue, documented in manufacturer TSB #9002688, points to the injector wiring loom and/or connector in the valve cover gasket area as a common point of failure for injector circuit codes (P0201-P0206). This should be the first place to inspect before considering injector replacement.
• Owners have also reported finding the wiring harness chafed and shorted near the oil filter, causing intermittent stalling and various circuit codes, including for injectors.

Mechanic-Grade Diagnostic Values

• Fuel Injector Coil Resistance (4.7L V8) — expected: 10.8 - 13.2 Ohms at 68°F (20°C). Failure: A reading of infinity (open circuit), zero (short), or a value significantly outside the specified range.
• Fuel Injector Coil Resistance (5.7L HEMI V8) — expected: ~12 - 14.5 Ohms at 68°F (20°C). Failure: A reading significantly different from other injectors (e.g., 17 ohms when others are 12.9) or an open/shorted reading.
• Injector Control Circuit to PCM Continuity — expected: Less than 5.0 Ohms. Failure: Resistance higher than 5.0 Ohms indicates an open or high resistance in the wire.
• Injector Control Circuit to Ground — expected: Greater than 100 ohms (ideally an open circuit/infinite resistance). Failure: Resistance below 100 ohms indicates a short to ground in the control circuit.

Scan Tool Commands That Help

• DRBIII, wiTECH, or advanced aftermarket scanner: Injector Kill Test / Injector Cutout Test — This bidirectional command allows the technician to shut off individual injectors one at a time while the engine is running. If shutting off cylinder #2 causes no change in engine idle, it confirms that injector is not contributing. If shutting it off makes the idle worse, the injector is working to some degree. This helps isolate whether the fault is causing a complete failure or an intermittent issue.

Wiring & Ground Locations

• Cylinder #2 Location — On both the 4.7L and 5.7L V8 engines, the cylinders are numbered front to rear, with odd numbers on the driver's side (left bank) and even numbers on the passenger's side (right bank). Cylinder #2 is the front-most cylinder on the passenger side.. Correctly identifying cylinder #2 is the first step in any diagnosis for a P0202 code.
• (K12) Injector Control No. 2 Circuit — This is the specific wire that runs from the Powertrain Control Module (PCM) to the fuel injector #2 connector. It is the control (ground-side) wire that the PCM pulses to fire the injector.. Service manuals refer to this circuit by its identifier (K12) when providing diagnostic steps for testing continuity or shorts.
• PCM Connector C2 — This is one of the main multi-pin connectors on the Powertrain Control Module. The specific pin for the (K12) circuit is located here.. Technicians must disconnect this connector to safely test the continuity of the injector wiring harness between the PCM and the injector without probing and damaging the PCM terminals.
• Engine Ground Strap — A primary engine-to-chassis ground strap is typically located on the passenger side, connecting the engine block or cylinder head to the frame or firewall. Other grounds are located near the battery negative terminal.. While not a direct cause of a single injector code, a poor main engine ground can cause a host of electrical issues, creating floating voltages and intermittent problems across multiple sensors and actuators, including injectors.

Real Owner Repair Stories

• DodgeForum.com user (2004 Dodge Ram 1500 5.7L HEMI) — Misfire on cylinder 2 and P0202 code.
  ❌ Tried (didn't work) Replaced all spark plugs and wires, Replaced fuel injector #2
  ✅ What actually fixed it The user reported the P0202 code remained after replacing the injector. Further diagnosis pointed to a wiring or PCM issue, consistent with the TSB and common failure patterns for this vehicle.

OEM Part Supersession History

• 5037479AC → 5037479AD, then 5037479AE — Standard part revision and improvement by the manufacturer.
  Heads up: Part number 5037479AC is listed as being replaced by 5037479AE. When ordering, using the latest part number (AE) is recommended to get the most current revision.
• 53032701AA → 53032704AB (for earlier 4.7L engines, verify fitment for 2007-2010) — Part revision.
  Heads up: It is critical to verify the correct injector part number by VIN for the 4.7L engine, as different numbers were used across its production run.

Model Year Variations Within This Range

• 2009-2010: The 5.7L HEMI engine was significantly updated for the 2009 model year (start of the 4th generation), gaining Variable Valve Timing (VVT) and more power. This resulted in different fuel injectors (e.g., 5037479AC) and potentially different PCM logic and wiring harness connectors compared to the 2007-2008 5.7L HEMI.