P2690 indicates that the data the Powertrain Control Module (PCM) has stored for the Cylinder 5 fuel injector does not match the values it expects. This most often occurs on engines with electronically calibrated injectors where individual injector trim or compensation values must be programmed into the PCM for proper fuel delivery.
On engines that store individual injector trim codes, a fresh injector must have its identification or quantity-adjustment values programmed into the PCM. Skipping this step is the single most common trigger for P2690.
Moving an injector from one cylinder to another changes which learned values the PCM expects, producing a data-mismatch code even though the injector itself is functional.
An injector with internal electrical problems, a short, or an open coil can return values the PCM interprets as out-of-range or incompatible with the stored calibration.
Corrosion, bent pins, oil intrusion, or a broken wire between the injector and PCM can corrupt the data exchange, causing the PCM to flag the injector as incompatible.
A failed software update, an improper reflash, or battery voltage events during programming can leave the PCM with an injector data set that does not match the engine.
Rare, but a damaged PCM can misread injector data or lose its learned injector values. This should be considered only after the more common causes above are ruled out.
Almost never. In the vast majority of cases the PCM is functioning correctly and is simply reporting that its stored injector calibration does not match the physical injector. Replacing the PCM is expensive and does not fix the underlying calibration or wiring issue. The PCM should be suspected only after injectors, wiring, and programming have all been verified.
Short-distance driving is usually possible, but the engine may run roughly, have reduced power, and produce elevated emissions. Prolonged driving with an injector data fault can lead to fuel wash, catalyst contamination, or unburned fuel reaching the exhaust.
No. Clearing the code erases the diagnostic trouble code but does not correct the underlying data mismatch. The code will return as soon as the PCM re-evaluates the injector on the next drive cycle.
Not necessarily. If the injector is electrically healthy and the code was triggered by a recent replacement, swap, or lost programming, simply entering the correct injector calibration into the PCM will often resolve the issue without replacing any parts.