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DTC codes / Ford codes / P1262

P1262 · FordCylinder 2 High To Low Side Short

P1262 on Ford vehicles indicates that the powertrain control module has detected a short between the high-side and low-side circuits of the fuel injector for cylinder 2. This means the injector coil is either internally shorted or the wiring harness has a chafed or pinched section where the two control wires touch, preventing the injector from opening and closing properly.

SystemPowertrain
Code typeFord specific
SeverityMedium
Fix difficultyIntermediate
AreaFuel and air metering (injector circuits)

Symptoms you may notice

  • Rough idle or misfire that is most noticeable when the engine is cold or under light load
  • Noticeable loss of power and poor acceleration because cylinder 2 is not contributing
  • Check engine light illuminated, often flashing if the misfire is severe enough to damage the catalytic converter
  • A distinct fuel smell from the exhaust or under the hood if the injector is stuck open and flooding the cylinder
  • Often no symptoms besides the warning light if the short is intermittent and the injector still fires under most conditions

Common causes, most likely first

  1. Internal short in the cylinder 2 fuel injector coil, where the windings have melted together
  2. Chafed or pinched injector harness wiring where the high and low control wires run together near the valve cover or intake manifold
  3. Corroded or water-intruded injector connector pins that bridge the high and low circuits
  4. Rodent damage to the injector harness insulation, exposing and shorting the two wires
  5. A failed powertrain control module injector driver that internally shorts the high and low outputs for cylinder 2
  6. Aftermarket or incorrectly routed wiring repairs from a previous job that left the high and low wires too close together

How to diagnose and fix it

  1. Inspect the cylinder 2 injector connector and the visible section of its harness for chafing, corrosion, or rodent damage before touching any parts
  2. Disconnect the injector and use a digital multimeter to measure resistance across the injector terminals, comparing it to a known-good injector on another cylinder
  3. With the injector unplugged and the key off, measure resistance between the two injector control wires at the harness connector to check for a short in the wiring itself
  4. Wiggle-test the harness while watching the multimeter or a lab scope to catch an intermittent short that only appears with engine vibration
  5. If wiring checks out, swap the cylinder 2 injector with a known-good injector from another cylinder and see whether the code follows the injector or stays on cylinder 2
  6. Repair any chafed wiring with proper solder and heat-shrink, replace a shorted injector, and clear the code to verify the repair with a road test
  7. If the short persists at the powertrain control module pins with the injector and harness disconnected, test the module driver circuit and replace the module only as a last resort

Why cylinder 2 injector shorts fool good technicians

  • A shorted injector often still allows the engine to run because the short may be intermittent, so a simple resistance check at room temperature can pass and send you chasing the wrong circuit
  • The high and low injector wires are twisted together in the factory harness, so a single chafe point can short both circuits and set P1262 even though the injector itself is perfectly healthy
  • Technicians frequently replace the cylinder 2 injector first and then find the code returns because the real fault is a pinched harness section behind the intake manifold that only shorts when the engine bay heats up
  • A failing powertrain control module driver for cylinder 2 can mimic a wiring short, so always disconnect the module and recheck the harness before condemning the computer
  • P1262 is often stored alongside misfire codes for cylinder 2, and clearing the misfire code without fixing the short will let the misfire return and possibly damage the catalytic converter

Can I keep driving with P1262?

You can drive a short distance to a repair shop if the engine is running smoothly and the check engine light is steady, but avoid heavy acceleration and long trips. If the light is flashing or you feel a strong misfire, stop driving because unburned fuel can overheat and destroy the catalytic converter.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for Ford vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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