2001 Nissan Liberty No Revs with P0650 and P0340 OBD2 Codes After Head Gasket Replacement
I own a 2001 Nissan Liberty that overheated and damaged the head gasket. I replaced the gasket, but now the vehicle is not responding to throttle—no revs at all. Using a Maxidas DS708 scanner, I'm seeing two OBD2 diagnostic codes: P0650 (Mil/Circ - Malfunction Indicator Lamp Circuit) and P0340 (Camshaft Position Sensor Circuit). What do these codes mean, and what steps should I take to resolve the issue? The vehicle has been running with no power, and I'm concerned about further engine damage.
The P0340 code typically indicates a problem with the camshaft position sensor circuit, which is likely contributing to the lack of engine revs. This sensor helps the ECU determine engine timing—failure or misalignment can cause stalling or no response to throttle. P0650 points to an issue with the MIL (Malfunction Indicator Lamp) circuit, suggesting a possible fault in the check engine light wiring or power supply, which may prevent the dashboard warning lights from functioning properly. For your 2001 Nissan Liberty, it's recommended to inspect the camshaft position sensor and its electrical connections. Also verify that the ECU is receiving proper signals after gasket replacement. If the sensor is faulty or loose, replacing it should restore engine responsiveness.