P0216 on 2021 Cadillac Escalade: Injection Timing Circuit Causes and Fixes

What's Unique About the 2021-2021 Cadillac ESCALADE NA

For this specific generation of Cadillac Escalade and its GM platform-mates (Tahoe, Yukon, Silverado), code P0216 is strongly linked to known manufacturing and design issues. Multiple Technical Service Bulletins (TSBs) confirm that the engine wiring harness is prone to chafing and damage in predictable locations. A key reason cited in TSB #21-NA-149 is a harness retaining clip that may have been omitted during assembly, allowing the harness to contact sharp edges. The TSB also notes that engine rock during normal driving can cause intermittent contact that may not be visible during a static inspection. Unlike many other vehicles where this code might point to a bad sensor or pump, on the 2021 Escalade, the root cause is overwhelmingly likely to be a wiring fault.

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
• Engine runs rough or has an uneven idle.
• Hesitation or stumbling upon acceleration.
• Noticeable loss of engine power.
• Vehicle may enter a reduced power 'limp mode'.
• Engine may misfire
• Vehicle may not start or be hard to start in severe cases.
• Dash messages like "Service Emission System" or "Reduced Acceleration" may appear.

Most Likely Causes

1. Engine Wiring Harness Chafing 🔴 High Probability → Shop Engine Wiring Harness TSB #21-NA-149 details how the engine harness can rub against the sharp edge of the ECM/TCM bracket, the driver-side upper control arm, and the shock tower bolt, causing wires to short out. This was sometimes caused by a harness retaining clip being omitted during assembly, allowing for excessive movement. On 3.0L diesels, additional chafe points are on top of the generator and near a PCV hose clamp.
   How to confirm: Perform a thorough visual inspection of the engine wiring harness. Per TSB #21-NA-149, this is best done by removing the driver's side front wheel and wheelhouse liner to gain access. Carefully check the known chafe points. The damage may be subtle and only visible when moving the harness, as engine rock can cause intermittent contact not present when the engine is off.
   Typical fix: Repair the damaged wires using approved splicing techniques with heat-sealable butt connectors. Protect the repaired section with anti-abrasion tape (such as Tesa tape) or a protective sleeve. Secure the harness away from sharp edges with zip ties to prevent future contact. GM has specific wire repair procedures that should be followed.
   Est. part cost: $10-$50
2. Faulty Fuel Injector Harness Connector (3.0L Diesel Only) 🔴 High Probability → Shop Fuel Injector TSB #22-NA-087 specifically identifies a broken terminal pin inside the #2 fuel injector harness connector as a common failure on the 3.0L LM2 Duramax engine. This issue is often accompanied by code P0202.
   How to confirm: If P0202 is also present, this is the most likely cause. Inspect the #2 fuel injector connector for damage or a broken terminal pin. The TSB notes the pin breaks internally, so careful inspection is needed. Also check for poor terminal tension at the main harness connector X160 as a secondary step.
   Typical fix: Per TSB #22-NA-087, the official repair is to replace both the affected #2 fuel injector and its corresponding wiring harness as a set.
   Est. part cost: $100-$450

Rare But Worth Checking

• Poor Terminal Tension at Connector X160: TSB #21-NA-149 and related GM documents specifically call out inspecting for poor terminal tension or a missing terminal locking feature at the X160 engine harness connector. A loose connection here can mimic a harness short and cause injector circuit codes.
• Failed High-Pressure Fuel Pump (Diesel Engine): → Shop Fuel Pump While wiring is the most common issue on this platform, a mechanical failure within the high-pressure injection pump can also cause injection timing faults. This would likely present with more severe running issues and should be considered only after all wiring issues are ruled out.
• Faulty Crankshaft or Camshaft Position Sensor: The ECM relies on these sensors for timing data. An erratic signal could theoretically trigger P0216, but this is far less likely than the known harness issues on this specific vehicle.

Diagnosis Steps

1. Scan the ECM for all stored trouble codes. Note any injector-specific codes (P0201-P0206) that are present with P0216, as this strongly suggests a wiring fault.
2. Carefully and thoroughly inspect the engine wiring harness for signs of chafing or damage. Per TSB #21-NA-149, remove the driver's side front wheel and wheelhouse liner for proper access. Pay close attention to the areas near the ECM/TCM bracket, on top of the generator (on diesels), and near the driver-side upper control arm and shock tower.
3. If the vehicle is a 3.0L Diesel and P0202 is present, inspect the #2 fuel injector connector for broken pins or damage per TSB #22-NA-087.
4. Inspect harness connector X160 for poor terminal tension or missing terminal locking features, as noted in TSB #21-NA-149.
5. If harness damage is found, repair the affected wires using GM-approved methods (splicing with heat-shrink connectors). Ensure the harness is then properly secured away from any sharp edges or moving parts.
6. If no harness damage is visible, test the injector control circuits for continuity and shorts to ground using a digital multimeter. Remember that a static test may not reveal an intermittent short caused by engine movement.
7. If all wiring and connectors are confirmed to be good, further diagnosis of the fuel injection pump (on diesels) or the ECM may be necessary, but this is rare.

Parts You'll Likely Need

• Engine Wiring Harness Repair Supplies — This is for repairing the most common cause: a chafed wiring harness. This includes wire, solder/butt-connectors, heat shrink, and anti-abrasion tape.
  Trusted brands: ACDelco, Tesa (for tape)
  OEM price range: $10-$50
  Aftermarket price range: $5-$30
• High Pressure Diesel Fuel Injector (Cylinder #2) (OEM #55506244) — Required for the 3.0L Diesel engine fix per TSB #22-NA-087, which instructs to replace the injector along with the harness when a broken connector pin is found.
  Trusted brands: ACDelco, Bosch
  OEM price range: $250-$400
  Aftermarket price range: $150-$300
• Fuel Injector Wiring Harness (3.0L Diesel) (OEM #40009605 (supersedes 55513485)) — The companion part for the injector replacement on the 3.0L Diesel, as specified by TSB #22-NA-087. Aftermarket pigtail connectors are also available for repair.
  Trusted brands: ACDelco (GM Genuine), Fleece Performance (pigtail)
  OEM price range: $80-$150
  Aftermarket price range: $40-$70

Related Codes That Often Appear With This One

• P0201 - P0206 — These codes indicate a circuit malfunction for a specific cylinder's injector. When seen with P0216, it strongly points to a widespread wiring harness issue affecting multiple injector circuits, as described in TSB #21-NA-149.
• P0202 — This code for 'Cylinder 2 Injector Circuit Malfunction' is very commonly seen with P0216 on the 3.0L LM2 Diesel. TSB #22-NA-087 specifically calls out this combination as pointing to the broken terminal pin in the #2 injector connector.

Technical Service Bulletins (TSBs) & Recalls

• 22-NA-087: Addresses a Malfunction Indicator Lamp (MIL) with DTCs P0201-P0206 and/or P0216 set. It identifies the cause on 3.0L LM2 engines as a broken terminal pin inside the #2 injector harness connector and directs replacement of both the injector and the harness.
• 21-NA-149: A comprehensive bulletin detailing several engine wiring harness chafing conditions on 2021+ GM trucks and SUVs that can cause a wide variety of DTCs, including P0216. It identifies specific chafe points and inspection/repair procedures.

Platform-Specific Known Issues

• TSB #21-NA-149 documents multiple locations where the engine wiring harness can chafe on both 6.2L V8 and 3.0L Diesel engines, causing this code. The primary spots are the ECM/TCM bracket, driver's side upper control arm, and shock tower bolt.
• TSB #22-NA-087 documents a specific issue on 3.0L Diesel engines where a terminal pin breaks inside the #2 injector connector, causing P0216, often with P0202. The official fix is to replace both the injector and the harness.

Mechanic-Grade Diagnostic Values

• Fuel Injector Resistance (3.0L LM2 Diesel) — expected: 160k - 190k Ω (160,000 - 190,000 Ohms). Failure: A reading significantly outside this range indicates a faulty piezo injector.
• Fuel Injector Resistance (6.2L L87 Gas) — expected: 1.5 - 2.2 Ω. Failure: A reading of infinity (open circuit) or near-zero (short circuit) indicates a faulty injector.
• Low-Side Fuel Pressure (3.0L LM2 Diesel, at idle) — expected: 60 - 70 PSI. Failure: Pressure below this range may indicate a weak lift pump or clogged filter.
• High-Side Fuel Pressure (3.0L LM2 Diesel, under load) — expected: Up to 36,260 PSI (2,500 bar). Failure: Inability to reach specified pressure under load can indicate a failing high-pressure pump, but wiring should be checked first.
• Injector Circuit Voltage (Key On, Engine Off) — expected: ~12V (Battery Voltage). Failure: Low or no voltage on the power supply wire to the injectors points to a problem in the power feed circuit.

Scan Tool Commands That Help

• GM GDS2: Injector Balance / Kill Test — To individually disable each fuel injector while monitoring engine RPM. A cylinder where disabling the injector causes no change in RPM indicates a problem with that injector or its circuit. This helps isolate the fault after confirming wiring integrity.
• GM GDS2: Injection Timing Test — Allows the scan tool to directly command and test the injection timing components, helping to differentiate between a wiring/control issue and a mechanical component failure.
• GM GDS2: Fuel Injector Flow Rate Programming — This is a mandatory service function that must be performed after replacing any fuel injector. Each new injector has a unique calibration code that must be programmed into the ECM for correct fuel delivery.

Wiring & Ground Locations

• X160 — Engine wiring harness, near the main breakout to the fuel injectors.. TSB #21-NA-149 and related documents specifically call for inspecting this connector for poor terminal tension or missing terminal locks when injector codes like P0216 are present. A loose pin here can cause an intermittent open circuit.
• G103 — Typically located on the firewall in the engine compartment, often above the brake booster.. This is a major ground point for numerous modules, including the Body Control Module (BCM) and Instrument Panel Cluster (IPC). While not a direct engine ground, a poor connection here can cause widespread electrical issues that could potentially affect ECM operation.
• Engine Block Ground — Main ground strap from the negative battery cable to the engine block, often on the left (driver's) side front of the block.. This is the primary ground reference for the ECM and all engine sensors. A loose or corroded connection here can cause erratic sensor readings and trigger a variety of engine-related fault codes, including timing circuit issues.

Real Owner Repair Stories

• Synthesized from GM TSB #22-NA-087 (2021 Cadillac Escalade with 3.0L LM2 Diesel Engine) — Check Engine Light on, engine runs rough.
  ❌ Tried (didn't work) Clearing codes without diagnosis., Inspecting only for visible harness chafing while ignoring connectors.
  ✅ What actually fixed it The issue was diagnosed by finding both P0216 and P0202 stored in the ECM. Following TSB #22-NA-087, the technician inspected the #2 fuel injector connector and found an internally broken terminal pin. The official GM-mandated repair was to replace both the #2 fuel injector (Part #55506244) and the fuel injector wiring harness (Part #40009605) as a set.

"I Checked Everything" — The Actual Cause

• A common diagnostic trap for this code is performing a static continuity or short-to-ground test on the engine harness and finding no faults. TSB #21-NA-149 explicitly notes that engine rock and vibration during normal driving can cause the harness to make intermittent contact with sharp edges (like the ECM bracket or shock tower bolt). This fault will not be present when the engine is off and stationary. A thorough visual and physical inspection of the harness at the known chafe points, even if it tests 'good' on a multimeter, is critical to finding the root cause.

OEM Part Supersession History

• 55513485 → 40009605 — Part has been updated by the manufacturer. The new part is the current service replacement.
  Heads up: The new part number 40009605 is the correct replacement for 55513485 and several other previous part numbers for the 3.0L Diesel injector harness.