P0216 on 2021-2022 Cadillac Escalade: Injection Timing Control Circuit Fixes

What's Unique About the 2021-2022 Cadillac ESCALADE

For this generation of Escalade and its GM T1 platform siblings (Silverado, Sierra, Tahoe, Yukon), P0216 is not a random failure but a well-documented pattern. General Motors issued multiple Technical Service Bulletins (TSBs) acknowledging that the engine wiring harness is prone to chafing against sharp edges in the engine bay. TSB #22-NA-087 specifically links P0216 with other injector codes on the 3.0L Duramax diesel, pointing to a broken terminal pin inside the #2 injector harness connector. TSB #21-NA-149 is even broader, detailing multiple chafe points on both gas and diesel models, including the ECM/TCM bracket, the generator, and the PVC hose clamp. This makes a wiring inspection the absolute first step, ahead of suspecting any major components.

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 (MIL) illuminated
• Driver Information Center messages like 'Service ESC', 'Service Emission System', 'Reduced Acceleration'.
• Rough or uneven idle
• Engine hesitation or stumbling on acceleration
• Noticeable loss of engine power or 'limp mode'
• Engine may stall, especially at low speeds
• Difficulty starting the engine
• Violent shaking or misfiring at highway speeds.

Most Likely Causes

1. Engine Wiring Harness Chafing or Damage 🔴 High Probability → Shop Engine Wiring Harness TSB #21-NA-149 documents this exact issue across all engines. The harness can rub against the ECM/TCM bracket, the generator (alternator) on the 3.0L diesel, the driver's side upper control arm, the shock tower bolt, or a PVC hose clamp, causing wires to short or break.
   How to confirm: Visually inspect the entire engine wiring harness. Pay close attention to the specific areas identified in TSB #21-NA-149. It may be necessary to remove the driver's side wheel and wheelhouse liner for better access. Also check for poor terminal tension at the main harness connector X160.
   Typical fix: Repair the damaged wires using solder and heat-shrink tubing. In severe cases, a harness section or the entire engine harness may need to be replaced. Reroute the harness and add protective conduit like Kevlar Velcro Sleeve (GM PN 84826758) and secure it with zip ties to prevent future chafing.
   Est. part cost: $10-$50 for repair materials, $800-$1600 for a new engine harness.
2. Faulty Fuel Injector Connector (Especially #2 on 3.0L Diesel) 🟡 Medium Probability → Shop Fuel Injector TSB #22-NA-087 specifically identifies a broken terminal pin inside the #2 injector harness connector as a cause for P0216 and related codes on the 3.0L LM2 engine.
   How to confirm: Disconnect the injector connectors (especially cylinder #2 on diesel models) and inspect for corrosion, backed-out pins, or broken locking tabs. A gentle pull test on the individual wires at the connector may reveal the break.
   Typical fix: Per TSB #22-NA-087, the official repair is to replace both the affected fuel injector (GM PN 55506244) and the entire injector wiring harness (GM PN 55513485, superseded by 40009605).
   Est. part cost: $20-$60 for a pigtail, $200-$400 if the injector and harness are replaced per the TSB.
3. Faulty High-Pressure Fuel Injection Pump (Diesel Only) ⚪ Low Probability → Shop Fuel Pump While P0216 can indicate a pump issue on other diesel vehicles, for the 3.0L Duramax in this platform, it is almost always a wiring fault. The pump should only be suspected after all TSB-related wiring checks have been exhausted.
   How to confirm: This requires advanced diagnostics with a scan tool capable of monitoring fuel rail pressure and injection timing commands versus actual values. This is typically diagnosed by a professional after ruling out all wiring issues.
   Typical fix: Replacement of the high-pressure fuel injection pump.
   Est. part cost: $1000-$2500+

Rare But Worth Checking

• Faulty Crankshaft or Camshaft Position Sensor: The ECM uses these sensors for all timing calculations. While not a common cause for this specific code on this platform, a failing sensor can provide erratic data, leading the ECM to incorrectly flag the timing control circuit. A different code, P0016, is more common for a direct cam/crank correlation issue.
• Faulty Engine Control Module (ECM): An internal failure of the injector driver circuit inside the ECM can cause P0216. This is very rare and should be the last consideration after all wiring and sensor possibilities have been exhaustively ruled out. TSBs explicitly warn that this is rarely the cause.

Diagnosis Steps

1. Scan the ECM for all stored trouble codes. Note if any specific injector codes (P0201-P0206) or misfire codes are present alongside P0216.
2. Perform a detailed visual inspection of the engine wiring harness, focusing on the known chafe points identified in TSB #21-NA-149: around the ECM/TCM bracket, on top of the generator (alternator), near the driver's side shock tower, and at the PVC hose clamp.
3. For 3.0L Diesel models, pay special attention to the #2 fuel injector connector for a broken terminal pin, as specified in TSB #22-NA-087.
4. Inspect the main harness connector X160 for damage, corrosion, or poor pin tension, as this is another specific checkpoint from TSB #21-NA-149.
5. If harness damage is found, repair the affected wires using approved methods and materials. Secure the harness with protective sleeving to prevent recurrence. Clear the codes and perform a test drive to see if the code returns.
6. If no wiring damage is visible, use a multimeter to check for continuity and shorts on the injection timing control circuit wires between the ECM and the relevant component (e.g., fuel pump or injectors).
7. If wiring and connectors are confirmed to be good, further professional diagnosis may be needed to test the high-pressure fuel pump (on diesel models), crankshaft/camshaft sensors, and the ECM itself.

Parts You'll Likely Need

• Engine Wiring Harness Repair Supplies — This is the most common fix due to the known chafing issue. You will need wire, solder, heat-shrink tubing, and protective conduit (e.g., GM PN 84826758).
  Trusted brands: 3M, Delphi
  OEM price range: $20-$50
  Aftermarket price range: $10-$40
• Fuel Injector Wiring Harness (3.0L Diesel) (OEM #40009605 (supersedes 55513485)) — TSB #22-NA-087 may require replacing this harness if a terminal is broken inside a connector, often at injector #2. Using the latest part number ensures you have the most updated design.
  Trusted brands: ACDelco, GM Genuine Parts
  OEM price range: $70-$150
  Aftermarket price range: $50-$120
• High Pressure Diesel Fuel Injector (3.0L Diesel) (OEM #55506244) — If TSB #22-NA-087 applies (broken pin in #2 connector), GM's procedure requires replacing the #2 fuel injector along with the harness.
  Trusted brands: ACDelco, GM Genuine Parts
  OEM price range: $150-$250

Related Codes That Often Appear With This One

• P0201, P0202, P0203, P0204, P0205, P0206 — These codes indicate a circuit malfunction for a specific injector. When seen with P0216, it strongly points to a common wiring harness issue affecting multiple circuits, as noted in TSBs #22-NA-087 and #21-NA-149.
• P0300, P0301-P0306 — These are misfire codes. If the injection timing is incorrect or an injector isn't firing properly due to a circuit fault, it will directly cause a misfire in the corresponding cylinder(s). A Reddit user with a 2022 Silverado 3.0L reported P0216 along with P0304 (Cylinder 4 Misfire) and P0204.

Technical Service Bulletins (TSBs) & Recalls

• 22-NA-087: Malfunction Indicator Lamp (MIL) Illuminated with DTC P0201, P0202, P0203, P0204, P0205, P0206 and/or P0216 Set.
• 21-NA-149: Engine Wire Harness Chafing / IPC Gauges Sweep / IPC Warning Message / SES/Check Engine/MIL / No Start / No Crank / Runs Rough / Stalls / Reduced Engine Power / Various DTCs. (Supersedes PIT5751C).

Platform-Specific Known Issues

• TSB #22-NA-087: Broken #2 Injector Connector Pin (3.0L Diesel): Addresses a Malfunction Indicator Lamp (MIL) with DTCs P0201-P0206 and/or P0216 on 3.0L diesel models. The cause is often a broken terminal pin inside the #2 injector harness connector. The official fix is to replace both the #2 injector and the injector wiring harness.
• TSB #21-NA-149: Widespread Engine Harness Chafing (All Engines): A broad bulletin covering 2019-2022 GM trucks and SUVs, including the Escalade. It details multiple locations where the engine wiring harness can chafe and cause a wide variety of DTCs, including P0216. Specific inspection points for P0216 include connector X160, the injector connectors, and areas near the ECM bracket and generator.

Mechanic-Grade Diagnostic Values

• Fuel Injector Resistance (3.0L LM2 Diesel Piezo Injector) — expected: 160k - 190k Ω (160,000 - 190,000 Ohms). Failure: A reading significantly outside this range indicates an internal injector fault.
• Fuel Injector Resistance (6.2L L87 Gas Solenoid Injector) — expected: 11 - 14 Ohms. Failure: A reading of infinite resistance (open circuit) or near-zero (short circuit).
• Low-Side Fuel Pressure (3.0L LM2 Diesel) — expected: 60 - 70 PSI at idle. Failure: Pressure below this range could indicate a weak lift pump or restriction, though this is not a primary cause of P0216.
• High-Side Fuel Pressure (3.0L LM2 Diesel) — expected: Up to 36,260 PSI (2,500 bar) under load. Failure: Inability to reach commanded pressure could indicate a high-pressure pump issue, but this should only be investigated after wiring is confirmed good.
• Injector Balance Rates (3.0L LM2 Diesel at idle) — expected: Typically +/- 4 mm³. Failure: A value consistently outside this range for a particular cylinder points to a problem with that injector or cylinder, after wiring issues are ruled out.
• Injector Circuit Voltage (Key On, Engine Off) — expected: ~12 Volts (Battery Voltage) on the power supply wire to the injector.. Failure: Low or no voltage indicates a problem in the power supply circuit, fuse, or relay.

Scan Tool Commands That Help

• GDS2 (GM Global Diagnostic System 2): Injector Test / Fuel Injector Balance — This is a critical bidirectional test to isolate a faulty injector. The tool commands each injector to fire and measures the corresponding drop in fuel rail pressure. An inconsistent drop for one cylinder points to a problem with that specific injector's flow, helping to distinguish a wiring fault from a mechanical injector problem.
• GDS2 (GM Global Diagnostic System 2): Cylinder Power Balance — This function disables one cylinder at a time and measures the drop in engine RPM. If disabling a cylinder causes little to no change in RPM, it confirms that cylinder was not contributing power, which is useful for verifying a misfire related to P0216.

Wiring & Ground Locations

• ECM/TCM Bracket — Driver's side of the engine bay, holding the Engine and Transmission Control Modules.. This is a primary chafe point identified in TSB #21-NA-149. The engine wiring harness can rub against a sharp edge on this bracket, damaging the wires for the injector circuits and causing codes like P0216.
• Connector X160 — Major engine harness connector on the 3.0L Duramax.. TSB #21-NA-149 specifically calls for inspecting terminal tension at this connector. Poor pin connections here can cause intermittent open circuits for multiple injectors, triggering P0216 and other P020x codes.
• Generator (Alternator) — Front of the engine on 3.0L LM2 diesel models.. TSB #21-NA-149 notes that the wiring harness can be pinched or chafed on top of the generator, causing shorts that lead to P0216.
• Ground G103 — Located at the rear of the left-hand (driver's side) cylinder head or on the cowl above the brake booster.. This is a primary engine and control module ground. A loose or corroded connection at G103 can cause widespread, erratic electrical issues, including faults in the sensitive injector control circuits.

Real Owner Repair Stories

• Reddit user in r/Diesel (2022 Silverado 1500 3.0L Duramax) — Violent shaking at highway speeds, Check Engine Light, 'Service ESC', 'Service Emission System', and 'Reduced Acceleration' messages. Codes stored were P0204, P0216, P0300, P0304.
  ❌ Tried (didn't work) The owner was on a road trip and limped the vehicle to a dealer; the initial post was seeking advice on the diagnosis.
  ✅ What actually fixed it Another user immediately identified the symptoms and code combination as being indicative of the known wiring harness chafing issue documented in GM's Technical Service Bulletins, confirming the TSBs as the primary diagnostic path.

"I Checked Everything" — The Actual Cause

• A common diagnostic trap for this code is performing only a visual inspection of the harness. A wire can be broken internally from stress or vibration, especially at the back of a connector, with the outer insulation still appearing intact. TSB #22-NA-087 identifies a broken terminal pin *inside* the #2 injector connector. This would not be found with a simple visual check. Technicians are advised to perform a gentle 'pull test' on each wire at the connector to reveal such hidden breaks.

OEM Part Supersession History

• 55513485 → 40009605 — This is the Fuel Injector Wiring Harness for the 3.0L LM2 Diesel. The part number has been superseded multiple times, indicating GM has made rolling revisions to the part, likely to improve its durability and resistance to the known chafing and connector pin issues.
  Heads up: When replacing this harness as directed by TSB #22-NA-087, it is critical to use the latest available part number (40009605) to ensure you have the most updated and robust version. Previous part numbers in the chain include 55513485, 55512145, 55510039, 55508024, and 40009103.

Model Year Variations Within This Range

• 2021-2022: The 2021-2022 Escalade with the 3.0L Duramax uses the first-generation version, RPO code LM2. For the 2023 model year (in trucks), GM introduced an updated version, the LZ0. The LZ0 features significant internal changes, including stronger steel pistons (vs. the LM2's aluminum), a retuned turbo, new fuel injectors, and cooling system updates, resulting in higher horsepower and torque. While the P0216 wiring issues are well-documented for the LM2, technicians should be aware that parts are likely not interchangeable between the LM2 and LZ0 engines and should always verify by VIN.