P2601 indicates the powertrain control module (PCM) has detected a performance problem in the electric coolant pump control circuit, specifically that the pump appears stuck off (not running when commanded). On most vehicles this is an electric auxiliary coolant pump or variable-speed electric water pump controlled by the PCM through a dedicated circuit, relay, or driver.
The most common cause. The pump motor, internal electronics, or impeller wears out and the pump stops spinning even when power is supplied, triggering the stuck-off detection.
A relay with burned or pitted contacts can fail to deliver power to the pump, so the circuit looks open to the PCM even though the pump itself is good.
Corroded, loose, chafed, or water-damaged connectors at the pump and a poor engine or chassis ground are a frequent source of this code, especially on pumps mounted low in the engine bay.
A blown fuse will drop the circuit and the PCM will flag the pump as inoperative. Always check the fuse before replacing parts.
Some PCM strategies flag a pump-performance fault if expected coolant flow (inferred from temperature behavior) is not achieved, which can happen with a very low coolant level or persistent air pockets.
Rare. The PCM's output stage for the pump can fail, but this should only be considered after the pump, relay, wiring, fuses, and grounds have all been verified good.
The definition is universal; the diagnostics are engine-specific. Open your vehicle for the codes documented for it:
No. Despite what some generic advice suggests, the PCM is one of the least common causes of P2601. The vast majority of cases are a failed electric coolant pump, a bad relay, a blown fuse, or wiring/connector problems. The PCM should only be considered after the pump, relay, fuse, and wiring have all been ruled out.
It is risky. If the electric coolant pump is not running, engine temperatures can rise quickly, especially under load or in hot weather, and overheating can cause serious engine damage. It is generally best to limit driving and address the issue promptly.
No. Clearing or resetting the code only erases the stored fault. If the underlying electrical or mechanical issue remains, the code will return, often within a single drive cycle.
Not always. The code is set when the PCM sees that commanded pump operation does not match expected electrical or temperature feedback. The fault can be caused by the pump itself, its relay, its fuse, its wiring and connectors, a low-coolant condition, or in rare cases a PCM driver issue.