P0651 · Manufacturer communications

BENTLEY · 2026-07-16

Service Info: Engine Control Module (ECM) 5V Reference Circuits. Customer statement / workshop findings: This TPI provides supplementary technical information to support diagnosis of ECM 5V reference circuit DTCs. It details the sensors associated with each reference circuit (A, B, and C) and outlines relevant guidance to assist in isolating faults when any of the following DTCs are stored in the Engine Electronics (diagnostic address: 0001) • Sensor Reference Voltage “A” Circuit – Open / High / Low (P0641, P0643, P0642) • Sensor Reference Voltage “B” Circuit – Open / High / Low (P0651, P0653, P0652) • Sensor Reference Voltage “C” Circuit – Open / High / Low (P0697, P0699, P0698)

BUICK, CADILLAC, CHEVROLET, GMC · 2021-04-09

This Preliminary Information communication provides information to the technician about vehicles that have a Service Engine Soon Malfunction Indicator Lamp. Technician may find Diagnostic Trouble Code P06DE set in the Engine Control Module. P0651 may also be set in the ECM with the P06DE. Technician must follow published Service Information diagnostics for P06DE. If diagnostics lead to removing the oil pan or engine oil pressure is below specification when hot, to inspect the oil piston nozzles for damage. Technician should replace the broken oil nozzle(s) as long as the engine does not have any damage which warrants engine replacement.