P2142 indicates that the powertrain control module (PCM) sees a higher than expected voltage on the circuit that commands the EGR throttle (exhaust gas recirculation) actuator. This usually means the control line is being forced to battery voltage (a short‑to‑power condition) or the actuator itself is failing to modulate properly. The condition can increase emissions, reduce fuel economy, and cause drivability issues.
The EGR throttle actuator can internally short or stick, pulling the control circuit to a high voltage. This is the most common source of the code.
A short to battery voltage, broken insulation, or corroded terminals in the harness can force the circuit high. Inspect the loom and pins for damage.
If the return path is interrupted, the PCM may read an abnormal voltage on the control line, triggering the code.
Rarely the PCM's internal output stage for the EGR circuit can fail, resulting in a high‑side short. Usually diagnosed after wiring and actuator are verified.
Large leaks can cause abnormal EGR feedback that may manifest as a high‑circuit reading, though they typically set other codes.
The vehicle can usually be driven short distances, but the underlying problem can affect emissions and performance, so repair should be scheduled promptly.
PCM failure is the least common cause. Most cases are resolved by repairing the wiring or replacing the EGR valve. PCM replacement should be considered only after those items are ruled out.
No, the O2 sensor operates on a separate circuit. If an O2 sensor fault is present, it will set its own diagnostic trouble code.
Keeping the engine bay clean, protecting wiring from heat and abrasion, and performing regular maintenance of the EGR system helps avoid the conditions that lead to P2142.