P2146 on 2011-2014 Chevrolet Camaro: Injector Wiring Causes and Fixes

What's Unique About the 2011-2014 Chevrolet CAMARO

On the 2011-2014 Camaro with a V6 engine (LLT or LFX), the fuel injector wiring harness is routed underneath the upper intake manifold. This specific routing makes it exceptionally vulnerable to being pinched, chafed against the cylinder head or engine block, or damaged during unrelated service, such as intake manifold removal. This specific design vulnerability is the primary reason P2146 is so common on this platform and is acknowledged by General Motors Technical Service Bulletin (TSB) #PIP4924D.

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 and may be flashing
• Engine runs very rough and misfires heavily
• Significant loss of engine power
• Engine is hard to start or stalls immediately after starting
• Vehicle may enter a reduced power or "limp mode"
• Noticeable raw fuel smell from the exhaust due to incomplete combustion

Most Likely Causes

1. Damaged Fuel Injector Wiring Harness 🔴 High Probability → Shop Engine Wiring Harness The harness is routed under the intake manifold on V6 engines, making it susceptible to being pinched against the block, chafed by vibration, or damaged during other maintenance. This is a widely known issue cited in GM TSB #PIP4924D and discussed extensively in owner forums.
   How to confirm: Visually inspect the entire length of the Bank 1 injector harness for damage after removing the intake manifold. Pay special attention to where the harness passes near intake mounting posts or the edge of the cylinder head. Check for continuity on each wire from the ECM connector to the injector connectors using a multimeter.
   Typical fix: Repair the damaged section of the harness with new wire and heat-shrink tubing, or replace the entire fuel injector harness. 🎬 Learn how to repair damaged wiring harnesses like a professional. Given the labor involved, replacement is often preferred.
   Est. part cost: $90-$180
2. Failed Fuel Injector ⚪ Low Probability → Shop Fuel Injector
   How to confirm: If an injector has an internal short to ground, it can disrupt the entire group circuit. After confirming the wiring is intact, test the resistance of each injector in Bank 1. A good high-impedance injector should read between 11.2 and 12.5 Ohms when the engine is cold. An out-of-spec reading indicates a failed injector. This is a much less common cause for a group code than a wiring fault.
   Typical fix: Replace the single faulty fuel injector.
   Est. part cost: $50-$150
3. Engine Control Module (ECM) Failure ⚪ Low Probability → Shop Engine Control Module (ECM)
   How to confirm: This should only be considered after all wiring and injectors have been exhaustively tested and confirmed to be good. This is the least likely cause. It requires advanced diagnostics to verify the injector driver circuit inside the ECM has failed.
   Typical fix: Replace and program the Engine Control Module.
   Est. part cost: $300-$800

Diagnosis Steps

1. Read the trouble codes with an OBD-II scanner and note all present codes and freeze frame data. Confirm P2146 is active.
🎬 See a quick overview of diagnosing the P2146 error code.
2. (V6 Engines) The primary suspect is the harness under the intake. Prepare for intake manifold removal by disconnecting the battery and relieving fuel pressure.
3. Remove the engine cover, air intake tube, and then unbolt and carefully lift the upper intake manifold. New gaskets will be required for reassembly.
4. Perform a thorough visual inspection of the Bank 1 (passenger side) injector harness. Look for any signs of pinching, chafing, melting, or broken wires. A common failure point is where the harness was pinched under a mounting boss for the intake manifold.
5. If no visible damage is found, disconnect the harness from the ECM and the Bank 1 injectors.
6. Using a digital multimeter on the continuity setting, test each wire between the ECM connector and its corresponding injector connector pin. An infinite resistance reading (OL) indicates an open circuit in the wire that must be repaired or the harness replaced.
7. Test the resistance (ohms) of each fuel injector in Bank 1. Compare the readings to the manufacturer's specification of 11.2-12.5 Ohms for a cold engine. A reading that is significantly different indicates a faulty injector.
8. If all wiring and injectors test good, the fault may lie within the ECM's injector driver circuit, which requires professional diagnosis.

Parts You'll Likely Need

• Fuel Injector Wiring Harness (Bank 1) (OEM #12690531 (replaces 12629928)) — This is the most common failure point due to its vulnerable routing under the intake manifold, leading to chafing or pinching.
  Trusted brands: ACDelco (GM Genuine), Standard Motor Products
  OEM price range: $100-$160
  Aftermarket price range: $80-$150
• Intake Manifold Gasket Set (OEM #Fel-Pro MS 96918 (aftermarket) or equivalent ACDelco) — Required when removing the intake manifold on V6 engines to access the injector harness. Never reuse old gaskets.
  Trusted brands: ACDelco, Fel-Pro
  OEM price range: $25-$50
  Aftermarket price range: $15-$35

Related Codes That Often Appear With This One

• P2149 — This is the equivalent code for Injector Group 'B' (Bank 2, driver's side). If both P2146 and P2149 appear, it may suggest a more widespread wiring issue, a problem with the main engine harness connection, or an ECM fault.
• P0201, P0203, P0205 — These are individual injector circuit codes for cylinders 1, 3, and 5 (Bank 1). P2146 is a group fault, so it is often accompanied by one or more of these specific codes for the injectors in that group, as noted in TSB #PIP4924D.

Technical Service Bulletins (TSBs) & Recalls

• PIP4924D: Addresses multiple fuel injector circuit codes, including P2146, and points to inspecting the fuel injector wiring harness for rub-through or internal wire opens. This is the primary guiding document for this specific failure.

Platform-Specific Known Issues

• A known issue, documented in GM Technical Service Bulletin #PIP4924D, involves the fuel injector wiring harness rubbing through or developing an internal open circuit. The bulletin instructs technicians to inspect this harness specifically when P2146 is present.
• Owner experiences on forums like Camaro5 frequently describe finding the harness pinched flat under one of the intake manifold mounting points 🎬 Watch this owner's walkthrough of fixing a mangled injector harness., causing an immediate open circuit.

Mechanic-Grade Diagnostic Values

• Fuel Injector Coil Resistance — expected: 11.2 to 12.5 Ohms (when engine is cold). Failure: A reading significantly outside this range, or OL (open circuit), indicates a failed injector.
• Injector Balance Test (Pressure Drop) — expected: The pressure drop across all injectors in a bank should be similar. GM specifies that the pressure drop for any one injector should not vary by more than 20% from the average of the others.. Failure: An injector with a significantly lower or non-existent pressure drop is likely clogged or not firing.

Scan Tool Commands That Help

• GDS2 / High-End Aftermarket (e.g., Autel): Automated Injector Balance Test — This functional test individually disables each injector and measures the corresponding drop in fuel rail pressure. It is used to identify a clogged or underperforming injector that may not have an electrical fault but is causing a performance issue. A significant deviation in pressure drop compared to other cylinders indicates a problem injector.
• GDS2 / Tech2: Cylinder Power Balance — This test monitors crankshaft speed while deactivating one cylinder at a time. It helps confirm which cylinder(s) are not contributing power, which is useful for verifying that the entire Bank 1 is dead, as expected with a P2146 code.

Wiring & Ground Locations

• G100 / G118 — On the rear of the RH (passenger side) cylinder head.. A poor ground connection at the cylinder head can cause erratic behavior and voltage issues for sensors and actuators on that bank, including the fuel injectors. While less common than a harness failure, it's a critical point to check for tightness and corrosion.
• G101 — On the RH (passenger side) inner fender, near the battery.. This is a major chassis ground. A fault here could cause widespread electrical issues, though it would likely trigger more codes than just P2146.
• ECM Connector X1 (LFX Engine) — The Engine Control Module (ECM) on the LFX V6 has three main connectors (X1, X2, X3). X1 is typically the blue connector.. The injector control circuits originate here. Technicians need to identify the correct connector and pins for continuity testing back to the injectors. For example, on some GM applications, the Bank 1 injector control signals are on pins like 50, 51, and 52 of the X1 connector.

OEM Part Supersession History

• 12629928 → 12690531 — Standard part revision and improvement by the manufacturer.

Model Year Variations Within This Range

• 2011: The 2011 model year uses the LLT 3.6L V6 engine. This engine has an aluminum intake manifold and a Bosch ECM.
• 2012-2014: Starting in 2012, the Camaro V6 switched to the LFX 3.6L engine. The LFX features a lighter composite intake manifold, integrated exhaust manifolds (eliminating traditional headers), and uses a Delphi ECM. While the P2146 wiring issue under the intake persists, some engine-specific parts and tuning software differ between the LLT and LFX.