P0262
Cylinder 1 Injector Circuit High
Encountering the engine check light code P0262 signifies an explicit mechanical or electrical operational breakdown categorized as "Cylinder 1 Injector Circuit High". Professional scanner tools usually flag this subsystem loop early on.
Driver's Summary
A P0262 fault code points directly to a problem with cylinder 1 injector circuit high that the ECM has confirmed over multiple drive cycles. In practice, this fault causes severe misfire, rich exhaust smell, stalling at idle. This condition is classified as high severity. Prompt diagnosis is essential to prevent cascading damage to related components.
Symptoms
Severe misfire, rich exhaust smell, stalling at idle
Common Causes
- Short to voltage in injector wiring
- Internally shorted fuel injector
- Clogged fuel injector
- Bad PCM ground
How to Fix
- 1 Repair short to battery voltage in harness
- 2 Measure injector resistance and replace
- 3 Perform fuel injector cleaning
- 4 Check and clean engine grounds
Technical Explanation
The ECM detects code P0262 by continuously monitoring the relevant sensor circuit against calibrated threshold values stored in its non-volatile memory. The PCM monitors crankshaft rotational velocity via the CKP sensor at a resolution of individual tooth gaps on the reluctor ring. A combustion event in each cylinder produces a measurable acceleration spike; its absence or weakness is flagged as a misfire event within a 200-revolution or 1000-revolution test window. The fault remains stored in memory even after the MIL is cleared; it becomes a confirmed DTC after failing two consecutive drive cycles, and the PCM logs a freeze frame record of the engine's exact operating state at the moment of detection.
Is It Safe to Drive?
This fault carries real mechanical risk. The root causes — including short to voltage in injector wiring — can trigger a chain reaction of component failures if the vehicle continues to be driven. Have it towed or drive directly to a shop without delay.
Mechanic's Pro Tip
Before replacing any component on P0262, spend 5 minutes inspecting the wiring harness and connector first — corrosion, chafed insulation, and backed-out pins cause the majority of these faults and cost nothing to fix. Use a multimeter to measure voltage drop across the connector pins under load; anything above 0.1V indicates excessive resistance that will cause intermittent failures even after replacing the sensor.
Wiring repair: $100; Injector: $200 - $450