What does code P1620 mean?

Q: What does code P1620 mean?

Low Coolant Circuit. P1620 on GM vehicles means the powertrain control module (PCM) has detected a fault in the low coolant circuit, which typically monitors the coolant level sensor in the radiator surge tank. The PCM expects a specific voltage or resistance signal from the sensor and sets this code when the signal falls outside the normal range, indicating an open, short, or out-of-range condition in the wiring or sensor itself.

DTC codes / GM codes / P1620

P1620 · GMLow Coolant Circuit

P1620 on GM vehicles means the powertrain control module (PCM) has detected a fault in the low coolant circuit, which typically monitors the coolant level sensor in the radiator surge tank. The PCM expects a specific voltage or resistance signal from the sensor and sets this code when the signal falls outside the normal range, indicating an open, short, or out-of-range condition in the wiring or sensor itself.

SystemPowertrain

Code typeGM specific

SeverityMedium

Fix difficultyIntermediate

AreaComputer and output circuits

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