U1510 on 2015-2017 Chevrolet Suburban: Active Grille Shutter vs. G218 Ground Fixes

What's Unique About the 2015-2017 Chevrolet SUBURBAN

This generation of GM trucks and SUVs (K2XX platform) is known for two distinct issues that can trigger a U1510 code. While the most direct cause is a frequently failing Active Grille Shutter assembly, a more notorious and widespread problem is a poorly secured Body Control Module ground known as G218. This ground issue can cause a cascade of communication codes, including U1510, making proper diagnosis critical to avoid replacing parts unnecessarily. The presence of other seemingly random electrical faults (like 'Service Stabilitrak' messages or stalling at low speeds) is the key clue that points toward the G218 ground.

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 is on.
• If caused by G218 ground: Flickering dash lights and headlights, especially when turning or braking.
• If caused by G218 ground: Engine may stall, especially when turning at low speeds.
• If caused by G218 ground: 'Service Power Steering' or 'Service Stabilitrak' messages may appear.
• If caused by G218 ground: Radio or HVAC display may go blank intermittently.
• If caused by G218 ground: Wipers may behave erratically.

Most Likely Causes

1. Faulty Active Grille Shutter Assembly 🔴 High Probability The actuator motor/module integrated into the shutter assembly is a very common failure point on this platform. The internal electronics fail, breaking communication on the LIN bus.
   How to confirm: Scan for codes. If U1510 is the only code present, this is the most likely cause. You can also test the 3-wire connector at the shutter for power (Violet/Blue wire), ground (Black wire), and a varying voltage signal on the LIN bus wire (Green/Violet wire). If power and ground are good but the signal is a flat, steady voltage instead of a fluctuating one, the shutter assembly has failed internally. A scan tool can also be used to command the shutters open and closed; if they don't respond, the part is bad.
   Typical fix: Replace the entire Active Grille Shutter assembly. The actuator module is not sold separately.
   Est. part cost: $200-$450
2. Poor Body Control Module (BCM) Ground at G218 🔴 High Probability A GM Technical Service Bulletin (PIT5405C, later superseded by 18-NA-161) identifies a design/assembly issue where sound insulation material can get trapped under the G218 ground stud, or the nut can be loose, causing a poor connection.
   How to confirm: Scan for codes. If U1510 appears with a variety of other communication codes (see 'Often Seen With Codes' section), this is the prime suspect. Visually inspect the G218 ground stud, located under the driver-side A-pillar trim near the speaker. Check for looseness or trapped insulation matting under the ground terminal eyelet.
   Typical fix: Disconnect the battery. Remove the nut, pull back or trim the insulation mat, clean the contact surfaces of the eyelet and body with sandpaper, and securely retighten the nut.
   Est. part cost: $0-$5

Rare But Worth Checking

• Damaged Wiring Harness: While less common than the two main causes, physical damage to the wiring leading to the grille shutter can cause an open or short, triggering the code. Always inspect the harness for chafing or breaks before replacing parts. TSB 21-NA-077 advises checking the X132 connector for broken wiring or corrosion.
• Faulty Engine Control Module (ECM): This is extremely rare. The ECM is the last component to suspect after all other possibilities, including wiring, have been exhaustively ruled out.

Diagnosis Steps

1. Perform a full vehicle code scan of all modules, not just the ECM. Save the full report.
2. Analyze the codes. Is U1510 the only code, or are there numerous other communication DTCs?
3. If multiple communication codes are present (especially from the TSB list): Immediately proceed to inspect the G218 ground. It is located on the driver's side, behind the interior A-pillar trim panel near the speaker. Check if the nut is loose or if the dash insulation mat is caught under the ground terminal. If found, disconnect the battery, clean and secure the ground, clear all codes, and re-test.
4. If U1510 is the only (or primary) code: The Active Grille Shutter is the main suspect. Gain access to the shutter's electrical connector behind the grille.
5. With the key on, back-probe the connector and check for battery voltage on the Violet/Blue wire and a good ground on the Black wire.
6. Check the LIN bus wire (Green/Violet) for a varying voltage signal. A scope will show a square wave data signal toggling between approximately 1V and battery voltage. If power and ground are present but the signal is missing or flat (stuck at battery voltage), the shutter assembly has failed internally.
7. If power, ground, or signal is missing, inspect the wiring harness back to the ECM for breaks, shorts, or corrosion, paying close attention to the X132 connector.
8. If all tests pass but the code persists, only then should a faulty ECM be considered.

Parts You'll Likely Need

• Active Grille Shutter Assembly (OEM #84715512 (superseded by 85524693)) — This is the most common part-based failure for an isolated U1510 code. The internal electronics of the actuator fail, and it is only sold as a complete assembly with the shutters.
  Trusted brands: ACDelco (GM Genuine), Dorman
  OEM price range: $350-$450
  Aftermarket price range: $200-$300

Related Codes That Often Appear With This One

• U0073, U0100, U0101, U0121, U0140, C0544, etc. — The presence of multiple, seemingly unrelated communication codes alongside U1510 is a strong indicator that the root cause is a systemic electrical problem, most notably the poor BCM ground at G218, as documented in TSB PIT5405C and 18-NA-161.

Technical Service Bulletins (TSBs) & Recalls

• PIT5405C: 'Steering Jerks Or Kicks Back / Reduced Power Steering Assist / Engine Stall / No Start / Service Stabilitrak / IPC / Radio / HVAC Goes Blank Various DTCs' - This bulletin directly links U1510 to a poor BCM ground at G218 as a potential cause for numerous electrical issues.
• 18-NA-161: This bulletin supersedes PIT5405C, updating the information and reaffirming the G218 ground as the cause for a wide range of electrical problems across the K2XX platform, including the Suburban.

Platform-Specific Known Issues

• G218 Ground Defect: TSBs PIT5405C and its successor 18-NA-161 detail a widespread issue where the main ground for the Body Control Module (G218) is compromised. This can be due to a loose nut or the dash insulator mat being incorrectly installed between the ground terminal and the vehicle body. This single point of failure can cause dozens of different trouble codes, intermittent stalling, loss of power steering, and flickering lights. Correcting this ground is a critical first step if multiple electrical issues are present. Owners on forums like TahoeYukonForum.com report these exact symptoms and confirm the G218 fix resolves them.

Mechanic-Grade Diagnostic Values

• LIN Bus Signal Voltage (Oscilloscope) — expected: A square wave toggling between a low of ~1V and a high of ~12V (or battery voltage).. Failure: A flat line at 0V (short to ground), a steady ~12V (short to power or internal module failure), or no signal at all.
• LIN Bus Signal Voltage (Multimeter on Peak Min/Max) — expected: A max reading of approximately 12V and a min reading of approximately 1V.. Failure: Readings that do not fluctuate or are stuck high or low.
• Negative Battery Cable Voltage Drop (During Cranking) — expected: Less than 200 mV.. Failure: A reading above 200 mV indicates high resistance in the cable, a potential cause of widespread electrical issues mimicking the G218 problem.

Scan Tool Commands That Help

• GDS2 or equivalent professional scan tool: Active Grill Air Shutter — Use this bidirectional control to command the shutters to open and close. If the shutters do not respond to the command despite having good power and ground, it confirms a failure of the shutter actuator/assembly. Some tools may list this under 'Function Test' or 'Output Controls'.

Wiring & Ground Locations

• G218 — Under the driver-side dashboard, behind the A-pillar trim, near the speaker.. This is the main ground for the Body Control Module (BCM). A poor connection here due to a loose nut or trapped insulation causes widespread communication codes, including U1510.
• Active Grille Shutter Connector — Behind the vehicle's front grille, plugged into the shutter assembly actuator.. This 3-wire connector provides power, ground, and the LIN bus signal to the shutter actuator. Testing at this connector is the primary way to diagnose a faulty shutter. Pin 1: Violet/Blue (Power), Pin 2: Black (Ground), Pin 3: Green/Violet (LIN Signal).
• X132 — The engine harness connector that joins the main harness to the Active Grille Air Shutter jumper harness.. TSB 21-NA-077 points to this connector as a potential point of failure due to broken wiring or corrosion, which would interrupt the LIN bus signal and set a U1510.
• Fuse F47 (Underhood) — In the underhood fuse block.. This fuse supplies power to the active grille shutter assembly. While a blown fuse is not a common cause, it should be checked before replacing parts.

Real Owner Repair Stories

• Reddit user DAT2824 (2017 Chevrolet Silverado 5.3L) — Check Engine Light with code U1510. Shutters were observed to be continuously opening and closing.
  ❌ Tried (didn't work) Received conflicting diagnoses from two different shops; one suggested shutter replacement, the other suggested a thermostat issue.
  ✅ What actually fixed it Replacing the active grille shutter assembly resolved the U1510 code.
• Reddit user stitchypoos (2018 Chevrolet Silverado) — Check Engine Light with code U1510. All HVAC systems were confirmed to be working correctly.
  ❌ Tried (didn't work) Initial diagnosis pointed to either HVAC or the active shutter.
  ✅ What actually fixed it The user confirmed that replacing the active grille shutter assembly fixed the Check Engine Light.
• YouTube channel 'Traildisc' (Personal pickup truck (model year appears to be K2XX)) — U1510 'Lost communication with active grill shutter actuator LIN bus' code that would return immediately after clearing.
  ❌ Tried (didn't work) N/A - Diagnosis was performed systematically.
  ✅ What actually fixed it Diagnosis with an oscilloscope on the LIN bus wire showed a steady 14.5V instead of a square wave, confirming an internal short in the shutter module. Replacing the entire active grille shutter assembly restored the correct 12V square wave signal and cleared the code without needing to use a scan tool.

OEM Part Supersession History

• 84715512 → 85524693 — Part number consolidation and potential design updates by the manufacturer.
  Heads up: Part number 85524693 also replaces previous numbers 84660015 and 84733814.