P1477 on 2014-2015 Ram 3500: Intake Air Diverter Valve Circuit Shorted to Ground Fixes

What's Unique About the 2014-2015 Ram 3500

On this specific generation of Ram HD trucks, P1477 is very frequently not a hardware failure. Multiple Technical Service Bulletins (TSBs) have been issued by FCA (now Stellantis) indicating that this code, often along with a batch of other seemingly unrelated codes, can be triggered by a software anomaly in the Powertrain Control Module (PCM). TSB 18-037-16 Rev. A is a primary example, which calls for reprogramming the PCM with updated software as the definitive fix. This makes checking the software calibration level the most critical first step, before any parts are replaced.

Diagnostic Flowchart

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

Symptoms You May Notice

• Check Engine Light (Malfunction Indicator Lamp, MIL) is on
• Reduced engine power or sluggish acceleration
• Noticeable blue-ish white smoke from the exhaust, as reported by owners.
• Truck may run well otherwise, with the CEL being the only symptom.

Most Likely Causes

1. Powertrain Control Module (PCM) Software Requires Update 🔴 High Probability Manufacturer TSBs #18-037-16, #18-054-16, and others explicitly list P1477 as one of several codes fixed by a PCM software update. This is a well-documented issue for this specific platform.
   How to confirm: A Ram dealer or a qualified shop with a wiTECH scan tool can check the current software calibration ID against the latest available version listed in the TSBs.
   Typical fix: Reprogramming (reflashing) the PCM with the latest software. This is a non-mechanical repair that simply updates the engine's operating instructions.
   Est. part cost: $0
2. Wiring Harness Chafed or Shorted 🟡 Medium Probability The code definition itself points to a "Circuit Shorted To Ground." Engine vibration and heat can cause the wiring harness leading to the Intake Air Diverter Valve to rub against brackets, other components, or the engine block, eventually wearing through the insulation.
   How to confirm: Visually inspect the entire length of the wiring harness leading to the Intake Air Diverter Valve. Pay close attention to any points where it bends or makes contact with metal parts. Perform a continuity test from the valve connector to the PCM connector to check for a short to ground.
   Typical fix: Repairing the damaged section of the wire and protecting it with loom or by re-routing it to prevent future chafing.
   Est. part cost: $5-$25
3. Failed Intake Air Diverter Valve ⚪ Low Probability
   How to confirm: If the PCM software is confirmed to be up to date and the wiring is inspected and tested as good, the internal position sensor in the valve has likely failed. The valve can be command-actuated with a high-end scan tool to check for response. Resistance checks across the sensor pins can also be performed.
   Typical fix: Replacement of the Intake Air Diverter Valve assembly. This is typically the last resort after ruling out software and wiring.
   Est. part cost: $200-$450

Rare But Worth Checking

• Blown Fuse: A video guide for 2013-2018 Ram trucks confirms that the intake air diverter valve circuit is protected by fuse F78 (a 10A fuse) in the main under-hood fuse box. While not a common failure point for this code, it's a quick and easy check that should not be overlooked.
• Failed Powertrain Control Module (PCM): This is extremely rare. The PCM should only be considered as the cause after all other possibilities (software, wiring, and the valve itself) have been exhaustively ruled out by a professional. 🎬 See a professional diagnostic test on a Ram 6.7 PCM A failed driver circuit within the PCM could theoretically cause this code.

Diagnosis Steps

1. Check for Technical Service Bulletins (TSBs). Use the vehicle's VIN to check for open recalls or relevant TSBs. The presence of TSB #18-037-16 Rev. A is a very strong indicator of a software issue.
2. If a relevant TSB exists, the primary repair is to have a dealer or qualified shop with wiTECH update the PCM software. This resolves the issue in the majority of cases.
3. If the code persists after a software update, check fuse F78 (10A) in the under-hood fuse box.
🎬 Watch: 6.7 Cummins TIPM diagnostics and connector replacement guide
4. Visually inspect the wiring harness running to the Intake Air Diverter Valve, which is located on the intake system near the engine. Look for any signs of rubbing, melting, or exposed wires, especially where the harness is secured or touches other components.
5. Using a multimeter, disconnect the valve and check for 5-volt reference, a good ground, and a signal wire at the electrical connector.
6. If power and ground are good, test the integrity of the signal wire between the valve connector and the PCM for a short to ground.
7. If wiring and software are confirmed to be good, the Intake Air Diverter Valve assembly is the likely culprit and should be replaced. The OEM part number is a Mopar 68210141AD.

Parts You'll Likely Need

• Intake Air Diverter Valve (OEM #68210141AD) — This part is replaced when its internal position sensor fails. This should only be done after ruling out the much more common software and wiring issues.
  Trusted brands: Mopar
  OEM price range: $300-$450
  Aftermarket price range: $200-$350

Related Codes That Often Appear With This One

• U110E — Lost Ambient Temperature Message. This code is frequently listed alongside P1477 in TSBs that are resolved with a PCM software update.
• P20E8 — Reductant Pressure Too Low. Also commonly grouped with P1477 in software-related TSBs.
• P2281 — Air Leak Between MAF And Throttle Body. Another code often resolved by the same PCM reflash that fixes P1477.
• P1475 — Intake Air Diverter Valve Out of Calibration/Missing Calibration. This code directly relates to the same component and often appears with P1477, pointing to an electrical or calibration issue. A user on Turbo Diesel Register reported having both codes simultaneously.

Technical Service Bulletins (TSBs) & Recalls

• Bulletin #18-037-16 REV. A: This is the key TSB. It explicitly lists P1477 - Intake Air Diverter Valve Position Sensor Circuit Shorted To Ground as a code that is resolved by reprogramming the PCM with updated software on 2015 Ram 2500/3500 trucks.
• Bulletin #18-054-16: Also lists P1477 as part of a group of DTCs that can be fixed with a software update, this one for 2014 models.
• Bulletin #1807622, #18-041-15 REV A: These bulletins also group P1477 with other codes that are addressed by PCM software updates, reinforcing the pattern.

Platform-Specific Known Issues

• Software Update is the Primary Fix: A significant number of 2014-2015 Ram trucks with the 6.7L Cummins engine can set code P1477 due to a software glitch. FCA (the manufacturer) released multiple TSBs to address this by reprogramming the PCM. Ignoring this and replacing hardware first is the most common misdiagnosis.
• source — On the Turbo Diesel Register forum, a member with a 2014 Ram 2500 reported getting codes P1477 and P1475 at only 1784 miles, along with blue-ish white smoke. Another member correctly identified the codes as relating to the intake air diverter valve and recommended a dealer visit under warranty, which aligns with the TSB-first approach.

Mechanic-Grade Diagnostic Values

• Intake Air Diverter Valve Connector Pin Voltages (Key On, Engine Off, Connector Disconnected) — expected: Pin 1: ~12V (Battery Voltage), Pin 2: 5V (Signal), Pin 3: Sensor Ground, Pin 4: 5V (Supply), Pin 5: Motor Ground.. Failure: Missing voltage on Pin 1, 4, or 5, or incorrect voltage on Pin 2 indicates a wiring or PCM issue. A reading of less than 50mV on ground pins is considered good.
• Continuity test for Intake Air Throttle Motor circuit — expected: Low resistance (less than 5 ohms) between the valve connector and the corresponding PCM pins.. Failure: High resistance or an 'OL' (Open Line) reading indicates a broken wire. A reading to ground on either wire indicates a short.

Scan Tool Commands That Help

• wiTECH (Dealer Scan Tool): Intake Throttle Actuator Test / EGR Airflow Control Valve Test — This is a bidirectional command used after confirming software is up-to-date and wiring has been checked. It commands the valve to open and close to verify if the motor and position sensor are responding correctly. This is the final step before condemning the part itself.

Wiring & Ground Locations

• PCM Connector C1 (D3838A) — The main engine computer (PCM/ECM) is located on the driver's side of the engine block. C1 is one of the large multi-pin connectors.. This connector contains the pins for the Intake Air Diverter Valve motor. Pin A14 (Brown/Tan wire) is for the motor positive, and Pin A15 (Brown/Yellow wire) is for the motor negative. These are the specific points to test for continuity back from the valve connector.
• Intake Air Diverter Valve Harness — The harness runs from the valve on the intake horn assembly towards the main engine harness.. This harness is prone to chafing. A key inspection point is anywhere the harness makes physical contact with metal brackets, the engine block, or other components. Excess engine movement from worn motor mounts can accelerate this wear.

Real Owner Repair Stories

• YouTube channel 'AutoNerdz' (2014 Ram 2500 6.7L Cummins) — Multiple communication and circuit low codes, including U010C (Lost Communication with Turbocharger).
  ❌ Tried (didn't work) Initial diagnosis pointed towards a faulty turbo actuator or wiring near the component.
  ✅ What actually fixed it The root cause was a corroded pin and terminal in the connector on the bottom of the TIPM (main fuse box). This created a power supply issue that affected multiple components. This is a relevant story for P1477 as a power supply fault from the TIPM could mimic a specific circuit short code, and it's a location that is often overlooked.

OEM Part Supersession History

• 68210141AC → 68210141AD — Standard part revision by the manufacturer, likely for improved durability or material changes.
  Heads up: The new part number (68210141AD) is the correct and direct replacement for the original.

Model Year Variations Within This Range

• 2014 vs 2015: While the root cause (software) and fix (PCM reflash) are the same, FCA issued separate TSBs for 2014 (TSB 18-054-16) and 2015 (TSB 18-037-16) models. This indicates that the specific software calibration files are different for each model year, and the correct update must be applied based on the vehicle's VIN.