A P0612 code in your 2020 Jeep Grand Cherokee indicates that the ECM has detected an error in its control of the A/C compressor clutch relay circuit. This doesn't mean your A/C isn't working—it means the ECM has identified an issue in its ability to properly command the relay that engages the A/C compressor.
A/C Relay Control System
Your Grand Cherokee's ECM controls when the A/C compressor engages through a relay circuit. When you press the A/C button, the climate control sends a request to the ECM, which then decides whether to engage the compressor based on various inputs like refrigerant pressure, engine temperature, and load conditions. P0612 indicates a fault in this control pathway.
Common Causes
A failed A/C relay is the most common cause—the relay may be stuck, have burnt contacts, or respond slowly. Wiring issues between the ECM and the relay, including shorts, opens, or high resistance, trigger this code. Low refrigerant causing rapid cycling may also set this code on some vehicles. In rare cases, the ECM's relay driver circuit itself has failed.
Symptoms in Your Grand Cherokee
The A/C may not engage at all, engage intermittently, or cycle rapidly on and off. You might hear clicking from the relay area when the A/C should be engaging. The check engine light illuminates, and depending on system design, the A/C button indicator may blink or remain off.
Diagnostic Steps
Locate the A/C compressor relay in the power distribution center. Test the relay by swapping it with an identical relay from a non-critical circuit. Check refrigerant pressure to rule out low charge causing abnormal cycling. Verify wiring between the relay socket and ECM for continuity and shorts. Monitor relay command with a scan tool while commanding the A/C on.