P0262 on 2010-2014 GMC Terrain: Cylinder 1 Injector Circuit High Causes and Fixes

What's Unique About the 2010-2014 Gmc TERRAIN

For this generation of the GMC Terrain and its sibling, the Chevrolet Equinox, injector circuit codes like P0262 are frequently linked to specific wiring harness issues. General Motors issued Technical Service Bulletin #PIP4924D, which covers the 2010-2014 Terrain and points to the fuel injector wiring harness rubbing through its insulation. Common chafe points are against the intake plenum, valve cover bolts, and the side of the cylinder head, making a thorough visual inspection of the harness a critical first step before replacing any parts. This issue is so prevalent that it affects a wide range of GM vehicles sharing these engines.

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
• Rough idle or engine stumbling
• Engine misfire, sometimes felt as a shake or shudder
• Hesitation and lack of power during acceleration
• Reduced fuel economy
• Engine may run loudly

Most Likely Causes

1. Damaged Engine Wiring Harness 🔴 High Probability → Shop Engine Wiring Harness As documented in TSB #PIP4924D, the injector wiring harness is known to rub against engine components. The engine's movement during normal operation can cause the harness to chafe against sharp edges on the intake plenum, valve cover bolts, fuel lines, or the side of the cylinder head. This wears away the wire's insulation, causing a short to voltage.
   How to confirm: Visually inspect the entire fuel injector wiring harness, paying close attention to areas where it contacts other engine parts. You may need to remove the engine cover and gently move the harness to see underneath it. Look for chafed, melted, or broken wires.
   Typical fix: Repair the damaged section of the wire using solder and heat-shrink tubing. Secure the harness away from the contact point using anti-abrasion tape and zip ties to prevent future rubbing. In severe cases, a harness pigtail or the entire engine harness section may need to be replaced.
   Est. part cost: $10-$50 for wire repair supplies
2. Faulty Cylinder 1 Fuel Injector 🟡 Medium Probability → Shop Fuel Injector The fuel injector itself can fail internally, causing an electrical short that leads to a high voltage reading. While less common than the wiring issue on this platform, it is still a frequent cause.
   How to confirm: Disconnect the injector and measure its resistance with a multimeter. Compare the reading to the manufacturer's specification (typically 11-14 ohms for the 2.4L I4, or 1.5-2.5 ohms for the V6 engines). A reading far outside this range indicates a faulty injector. A definitive test is to swap the cylinder 1 injector with another cylinder's injector (e.g., cylinder 2). Clear the codes and drive the vehicle. If the code changes to P0265 (Cylinder 2 Injector Circuit High), the injector is confirmed to be the problem.
   Typical fix: Replace the cylinder 1 fuel injector. It is often recommended to replace the seals for adjacent injectors at the same time. For direct injection engines (3.0L, 3.6L), this is a more involved job.
   Est. part cost: $75-$300
3. Bad Electrical Connector ⚪ Low Probability The connector at the fuel injector can become loose, corroded, or contaminated with oil, leading to a poor connection and high circuit resistance. The locking tabs can also become brittle and break.
   How to confirm: Disconnect the connector and inspect the pins for corrosion, damage, moisture, or being bent. Ensure it clicks securely into place. Wiggle the connector with the engine running to see if it affects the idle.
   Typical fix: Clean the connector terminals with electrical contact cleaner and apply dielectric grease to prevent future corrosion. If the connector or pins are damaged, the pigtail connector will need to be replaced.
   Est. part cost: $15-$40 for a new pigtail connector

Rare But Worth Checking

• Faulty Powertrain Control Module (PCM): → Shop Engine Control Module (ECM) This is rare. The PCM's internal driver for the injector can fail, but all other possibilities like wiring and the injector itself should be exhaustively ruled out before condemning the PCM. A failed PCM is the least likely cause.

Diagnosis Steps

1. Read the trouble codes with an OBD-II scanner and note any other codes present, especially misfire codes (P0301) or other injector codes.
2. Visually inspect the engine wiring harness for any signs of chafing, melting, or damage. Pay extremely close attention to where the harness routes over the intake plenum, near valve cover bolts, and against the side of the cylinder head, as per TSB #PIP4924D.
3. Inspect the electrical connector on the cylinder 1 fuel injector for corrosion, damage, or a loose fit. Ensure the locking tab is secure.
4. Disconnect the injector and measure its internal resistance with a multimeter. A typical reading should be between 12-16 ohms. An open circuit (infinite resistance) or a dead short (zero resistance) indicates a failed injector.
5. If the injector resistance is good, perform a 'noid' light test on the injector connector. The light should flash steadily as the engine is cranked, indicating the ECM is sending a pulse signal. A steady-on light could indicate a short to power in the harness.
6. If you have access to a scan tool with live data, observe the fuel trim values. High fuel trim on Bank 1 could be related to the fueling issue.
7. The most definitive test: Swap the cylinder 1 injector with the cylinder 2 injector. Clear the codes and drive the vehicle. If the fault code changes to P0265 (Cylinder 2), the injector is faulty. If the P0262 code returns, the problem is in the wiring or the ECM.
8. If the problem remains with cylinder 1 after the swap, perform a continuity test on both wires in the injector circuit from the ECM connector to the injector connector to check for opens or shorts to ground/power.
9. If wiring and the injector are confirmed to be good, the issue may be with the PCM, but this should be the absolute last resort.

Parts You'll Likely Need

• Fuel Injector (OEM #12669384 (2.4L), 12638530 (3.6L V6)) — If the injector's internal coil has shorted, it will cause a high voltage condition and must be replaced.
  Trusted brands: ACDelco, Bosch, Standard Motor Products
  OEM price range: $100-$160
  Aftermarket price range: $50-$90
• Wiring Harness Repair Supplies — This is the most common cause for this vehicle, as per GM's TSB. You will need wire, solder, heat-shrink tubing, and anti-abrasion loom/tape to properly repair the chafed section.
  Trusted brands: 3M, Tesa
  OEM price range: $10-$50
  Aftermarket price range: $5-$25
• Fuel Injector Connector Pigtail (OEM #ACDelco PT2183 (example, verify fitment)) — If the connector itself is damaged, corroded, or has broken locking tabs, it must be replaced to ensure a solid connection.
  Trusted brands: ACDelco, Dorman
  OEM price range: $25-$40
  Aftermarket price range: $15-$25

Related Codes That Often Appear With This One

• P0301 — This code means 'Cylinder 1 Misfire Detected.' It is a direct symptom of the P0262 fault, as the injector circuit problem causes improper fueling, leading to a misfire.
• P0201 — This is a general fault code for the 'Cylinder 1 Injector Circuit.' It may appear alongside P0262, especially if the electrical fault is intermittent.
• P0261 — This is 'Cylinder 1 Injector Circuit Low.' Seeing both high (P0262) and low (P0261) codes can point towards an intermittent short in the wiring harness.

Technical Service Bulletins (TSBs) & Recalls

• PIP4924D: SES Light And Misfire With Injector Codes. This TSB highlights the common issue of the injector wiring harness rubbing through and causing various injector circuit faults. It lists specific chafe points to inspect, such as against the intake plenum and valve cover bolts.

Platform-Specific Known Issues

• Technical Service Bulletin #PIP4924D was issued by GM for a variety of injector circuit codes, including P0262. It specifically instructs technicians to carefully inspect the fuel injector wiring harness for rubbing through against engine components, which is a known point of failure on the 2010-2014 Terrain.
• Owners on forums frequently report solving P0262 and related misfire codes by finding a chafed wire in the harness that runs over the top of the engine, often near the back by the firewall or where it bends around brackets.

Mechanic-Grade Diagnostic Values

• Fuel Injector Resistance (2.4L I4 Engine) — expected: 11 - 14 ohms. Failure: A reading near zero ohms indicates a shorted coil; an infinite reading (OL) indicates an open coil.
• Fuel Injector Resistance (3.0L/3.6L V6 GDI Engines) — expected: 1.5 - 2.5 ohms (general specification). Failure: A reading outside the specification, or one that is significantly different from the other injectors, indicates a fault.
• Injector Pulse Width (at idle, via scan tool) — expected: Typically under 1 ms for GDI, but can be 2-4 ms.. Failure: A value of 0 ms for cylinder 1, or a value significantly different from other cylinders, points to a command or circuit fault. A much longer pulse width on one cylinder can indicate the ECM is compensating for a clogged injector.
• Injector Power Wire Voltage (Key On, Engine Off) — expected: ~12 Volts (Battery Voltage). Failure: Voltage significantly below battery voltage points to high resistance in the power supply circuit.

Scan Tool Commands That Help

• GDS2 (GM Factory Tool) or equivalent Pro-Level Scanner: Fuel Injector Balance Test — After confirming wiring integrity, this automated test helps identify a mechanically weak, restricted, or leaking injector that may not have an electrical fault. The tool fires each injector and measures the corresponding drop in fuel rail pressure, comparing the variance between cylinders.
• Most Bi-Directional Scan Tools: Cylinder Power Balance / Individual Injector Control — To manually disable the cylinder 1 fuel injector while the engine is idling. If disabling the injector causes no change in engine RPM or smoothness, it confirms that cylinder 1 was not contributing, which is the expected result with a P0262 fault.

Wiring & Ground Locations

• Cylinder #1 Injector Location (V6) — On the 3.6L V6 engine, cylinder #1 is on the right cylinder bank (the bank closer to the firewall/bulkhead).. Correctly identifying cylinder #1 is the first step to avoid diagnosing the wrong component.
• G103 (ECM Ground) — On the front of the right side (passenger side) cylinder head.. This is a primary ground for the Engine Control Module (ECM). A poor connection here can cause erratic behavior and false codes from any sensor or actuator controlled by the ECM, including the injector driver circuits.
• G105 / G109 / G112 — These are key engine block/head grounds. On the 2.4L, G105 is at the rear and G109 is at the top rear of the engine. On the 3.6L, G112 is at the left rear of the engine.. The ECM relies on clean, secure engine grounds to accurately control injector circuits. A loose or corroded ground can create voltage offsets and trigger circuit high/low codes.
• Engine Control Module (ECM) — Located in the engine bay, at the left front of the engine compartment.. This is the source of the injector control signal and where the circuit fault is detected. Knowing its location is necessary for advanced wiring tests (continuity/short checks).

OEM Part Supersession History

• 12638530 → 12669384 — Standard part lifecycle update by the manufacturer.
  Heads up: Part 12669384 is the correct current replacement for the 3.6L V6 injector. It also replaces older numbers 12611545 and 12632255. Using the superseded part numbers may result in getting old stock.

Model Year Variations Within This Range

• 2010-2012: The optional V6 engine was the 3.0L LF1. The standard I4 engine was the 2.4L LAF (2010-2011) and then the E85-capable 2.4L LEA (2012).
• 2013-2014: The optional V6 engine was upgraded to the 3.6L LFX, which uses different fuel injectors (PN 12638530, superseded by 12669384) and has cylinder #1 located on the rear cylinder bank.