P0513 on 2014-2019 GMC Sierra 1500: Causes and Fixes for Incorrect Immobilizer Key

What's Unique About the 2014-2019 Gmc SIERRA 1500

While the universal definition for P0513 points to a bad key, on the 2014-2019 GMC Sierra 1500 and its platform-mate, the Chevrolet Silverado, this code is frequently a symptom of underlying electrical issues specific to this platform. Manufacturer Technical Service Bulletins (TSBs) repeatedly link this code to a faulty Body Control Module (BCM) ground (G218) and to damaged wiring in the driver's side door sill. Owners should investigate these known electrical weak points before spending money on replacing keys or security modules.

Diagnostic Flowchart

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

Symptoms You May Notice

• Engine may not crank or start
• Engine starts and then immediately stalls
• Security light illuminated or flashing on the dashboard.
• Check Engine Light is on
• Service Engine Soon (SES) light may fail to illuminate when the key is in the 'run' position, as noted in TSB #PIT5391F.
• Service 4WD message may appear, as noted in TSB #PIT5391A and #PIT5391F.
• Various other electrical issues like the radio/HVAC display going blank, as the root causes affect shared electrical circuits.

Most Likely Causes

1. Poor Body Control Module (BCM) Ground (G218) 🔴 High Probability TSB #PIT5405C specifically identifies the dash insulator mat getting trapped under the G218 ground eyelet during factory assembly, causing a poor connection for the BCM. This is a widely documented failure point.
   How to confirm: Locate the G218 ground on the driver's side A-pillar, near the floor, often behind the kick panel and under the carpet/insulation. Remove the 10mm nut and inspect for the black foam insulator mat, corrosion, or paint preventing a clean metal-to-metal connection. A YouTube video by 'GMC and Chevy Truck Life' titled 'G218 Ground Issue Fix (2014 - 2018 Chevy Silverado GMC Sierra)' provides a clear visual guide. 🎬 Watch this visual guide to fixing the G218 ground issue.
   Typical fix: Disconnect the vehicle battery. Remove the ground nut (typically 10mm). Cut away any trapped insulation mat. Clean the eyelet terminal and the body surface to bare metal using a wire brush or sandpaper. Securely re-fasten the ground nut, ensuring no material is trapped underneath. Reconnect the battery.
   Est. part cost: $0-$5
2. Damaged or Corroded Wiring at Driver's Sill Plate 🔴 High Probability TSB #PIT5391F points to this area as a common failure point. Water and debris get trapped under the plastic sill plate, causing wires in the main harness to corrode and break. Specifically, circuit 5199, which powers the KR73 Ignition Run Relay, is often the culprit.
   How to confirm: Remove the driver's side plastic sill plate and kick panel. Carefully peel back the electrical tape or loom on the main wiring harness running along the floor. Inspect individual wires for green or white corrosion, swelling, or obvious breaks. The wires are often very thin and can break internally with no visible damage to the insulation.
   Typical fix: Cut out the damaged section of wire and splice in a new piece using butt connectors with heat shrink to seal the repair from future moisture. Solder and heat shrink provide a more robust repair.
   Est. part cost: $5-$20
3. Weak or Failing Vehicle Battery 🟡 Medium Probability Modern trucks have a high electrical demand. Low system voltage can cause communication errors between modules, including the BCM and PCM, leading to a P0513 code. TSB #18-NA-161 also details issues with high resistance in battery cables on these trucks. TSB #21-NA-277 also notes that P0513 can appear after a low voltage condition, jump start, or battery replacement.
   How to confirm: Test the battery voltage with a multimeter. A healthy battery should read approximately 12.6 volts with the engine off and above 13.7 volts with the engine running. Perform a load test, as a battery can show good voltage but fail under load. Many auto parts stores will test your battery for free.
   Typical fix: Replace the vehicle's 12V battery. Ensure terminal connections are clean and tight, torqued to 7 Nm (62 lb-in) per TSB #PIT5405C.
   Est. part cost: $150-$300
4. Defective Transponder Key or Key Fob Battery ⚪ Low Probability
   How to confirm: First, try replacing the battery in the key fob. If that doesn't work, try starting the vehicle with a spare key. If the spare key works consistently, the original key is likely faulty. This should only be considered after verifying the G218 ground and sill plate wiring are intact.
   Typical fix: Replace the key fob battery or replace and reprogram the entire key. Key replacement and programming often require a dealership or automotive locksmith.
   Est. part cost: $5-$400

Rare But Worth Checking

• Faulty Body Control Module (BCM): While rare, if the G218 ground is perfect and wiring is intact, the BCM itself can fail. This is an expensive last resort and should be professionally diagnosed.
• Faulty Underhood Fuse Block (UBEC): In some cases, internal corrosion or a failure within the underhood fuse block can cause a loss of power to critical circuits, mimicking the symptoms of a wiring break. A 2012 Sierra with P0513 had this issue, though it's less common for the 2014+ models.
• Faulty Engine Control Module (ECM): An internal failure of the ECM can prevent it from communicating correctly with the theft deterrent system. This is very uncommon and should only be considered after all other possibilities are exhausted.

Diagnosis Steps

1. Read all stored fault codes with an OBD-II scanner. Note any other communication (U-codes) or Body (B-codes) that are present, as they strongly point towards a wiring or ground issue.
2. Check the vehicle's battery. Ensure it has at least 12.6V engine-off and passes a load test.
3. Inspect Ground G218: This is the most critical first step. Access the driver's side A-pillar kick panel area. Locate the ground stud. Remove the 10mm nut and check for the dash insulator mat being pinched under the ground ring terminal. Cut away the mat, clean the contacts to bare metal, and re-secure.
4. Inspect Sill Plate Wiring: If the ground is good, remove the driver's side door sill plate and carefully unwrap the wiring harness. Look for any signs of blue/green corrosion, swelling, or broken wires. Pay close attention to circuit 5199 (often a small gauge wire). Repair any compromised wires found.
🎬 Watch this walkthrough for finding and fixing common GM ground issues.
5. If available, try starting the vehicle with a known-good spare key to rule out a faulty primary key. This is a low-probability cause but easy to test.
6. If the above steps do not resolve the issue, further diagnosis of the Body Control Module (BCM) and its circuits may be required, which might necessitate professional assistance.

Parts You'll Likely Need

• Wire Repair Supplies — The most common fixes involve repairing corroded wires under the driver's sill plate or cleaning a ground connection, not replacing a major component.
  Trusted brands: 3M
  Aftermarket price range: $5-$20
• Transponder Key (OEM #23209428) — If the key itself is confirmed to be faulty (after checking wiring and grounds), a replacement will be needed. This is a less common cause for this specific vehicle.
  Trusted brands: ACDelco, GM Genuine
  OEM price range: $150-$300
  Aftermarket price range: $70-$150

Related Codes That Often Appear With This One

• U0073, U0100, U0101, U0121, U0140, C0544 — TSB #PIT5405C lists a large number of communication codes that can appear alongside P0513, all pointing to the common cause of a bad BCM ground at G218.
• P262B, P0650, B1325, B1370 — TSB #PIT5391F associates these codes with P0513, often related to wiring issues in the driver's sill plate (specifically circuit 5199) causing multiple electrical faults, including a non-functional check engine light.

Technical Service Bulletins (TSBs) & Recalls

• PIT5391F: Mentions P0513 with a non-functional Service Engine Soon light, directing technicians to inspect wiring at the driver's sill plate for damage or corrosion, specifically circuit 5199.
• PIT5405C: Links P0513 with numerous other communication codes, identifying the root cause as a poor BCM ground at the G218 location due to a trapped insulator mat.
• PIT5391A: Predecessor to PIT5391F, also pointing to sill plate wiring issues for P0513 and other electrical faults.
• 21-NA-277: Notes that P0513 can appear after a low voltage event (like a jump start or battery change) and advises against immediately replacing modules without further diagnosis.

Platform-Specific Known Issues

• A faulty ground at location G218 is a well-documented issue. TSB #PIT5405C notes that the dash insulator mat can get caught under the ground connection during assembly, leading to a host of electrical problems, including P0513. There are numerous owner accounts and videos online detailing this exact fix.
• The wiring harness that runs under the driver's side door sill is susceptible to moisture intrusion, leading to corrosion and broken wires. TSBs #PIT5391F and #PIT5391A specifically call out inspecting this area for damage when P0513 is present, often involving circuit 5199.

Scan Tool Commands That Help

• Manual Procedure (No Tool Required): 30-Minute Security Relearn Procedure — Use after replacing a key, BCM, or ECM, or after resolving a power/ground issue that caused the system to lose its key programming. This procedure allows the vehicle's security system to learn the transponder value of the key.

Wiring & Ground Locations

• G218 — Driver's side A-pillar, near the floor, behind the kick panel and under the carpet/insulation.. This is the primary ground for the Body Control Module (BCM). TSB #PIT5405C identifies that the dash insulator mat often gets trapped under this ground from the factory, causing a poor connection and leading to P0513 and numerous other electrical faults.
• Driver's Sill Plate Harness — Runs along the floor under the driver's side plastic door sill plate.. This harness is prone to moisture damage. TSB #PIT5391F specifically calls out inspecting 'Circuit 5199' in this harness for corrosion or breaks, which can cause a no-start and set a P0513 code.
• BCM Fuses (Instrument Panel) — Fuse block on the side of the dashboard, accessible when the driver's door is open.. Multiple fuses power the BCM. Specifically, fuses F6, F7, and F17 in the driver-side instrument panel fuse block are critical for BCM operation and should be checked during diagnosis.
• BCM Fuses (Passenger Side) — Fuse block on the side of the dashboard, accessible when the passenger door is open.. Additional BCM-related fuses are located on the passenger side. Fuses F7, F8, F28, F45, and F46 in this panel are tied to the BCM and its functions and should be verified.

Real Owner Repair Stories

• YouTube Commenter on 'GMC and Chevy Truck Life' video (GMC Sierra / Chevy Silverado (2014-2018)) — Unspecified issues related to a bad ground, which the video addresses.
  ❌ Tried (didn't work) Spent hours searching on Google for a solution to the ground issue.
  ✅ What actually fixed it Following the video's instructions to access the G218 ground, move the insulation foam, and secure the connection fixed the truck in 30 minutes.

OEM Part Supersession History

• 25835966 → 13594692 — Part update/revision by manufacturer.
  Heads up: The BCM for 2014-2015 models may have a different part number than 2016-2019 models due to mid-cycle updates. Always verify the correct part number by VIN. A replacement BCM, new or used, requires programming to the vehicle's VIN to function.