P0641 · 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)

CHEVROLET, GMC · 2020-12-22

This Preliminary information communicates an issue with the engine wiring harness shorting at the left front cylinder head causing any of the following issues: - IPC gauges sweeping while driving - Several IPC warning messages and MIL displayed - Any combination of the following DTC's: U0073 U0100 U0101 U0121 U0128 U0129 U0131 U0140 U0146 U0422 U2413 P0107 P0117 P0119 P0641 C2A07

CHEVROLET, GMC · 2020-05-07

This Preliminary information communicates an issue with the engine wiring harness shorting at the left front cylinder head causing any of the following issues: - IPC gauges sweeping while driving - Several IPC warning messages and MIL displayed - Any combination of the following DTC's: U0073 U0100 U0101 U0121 U0128 U0129 U0131 U0140 U0146 U0422 U2413 P0107 P0117 P0119 P0641 C2A07

CADILLAC, CHEVROLET, GMC · 2020-04-21

This Preliminary information communicates The vehicle may have an SES lamp with any of the following DTC P06DA, P06DB, P06DC, P250A, P0300, P0340, P0341, P0335, P0336, P0641, P0011, P0010, P2088, P2089, and/or P2230. Possible crank no start or a stall. Possible wiring jumper harness pintched between the X154 connector bracket and the front engine cover on lower left side of the engine.

CHEVROLET, GMC · 2019-09-30

This Preliminary information communicates an issue with the engine wiring harness shorting at the left front cylinder head causing any of the following issues: - IPC gauges sweeping while driving - Several IPC warning messages and MIL displayed - Any combination of the following DTC's: U0073 U0100 u0101 u0121 u0128 U0129 u0131 U0140 U0146 U0422 U2413 P0107 P0641 C2A07

CADILLAC, CHEVROLET, GMC · 2018-09-11

This Preliminary information communicatesThe vehicle may have an ses lamp with any of the following DTC P06DA, P06DB, P06DC, P250A, P0300, P0340, P0341, P0335, P0336, P0641, P0011, P0010, P2088, P2089, and/or P2230. Possible crank no start or a stall. possible wiring jumper harness chaffed at the bolt at the X154 connector on lower left side of the frount cover.

CADILLAC, CHEVROLET, GMC · 2018-02-02

This Preliminary information communicatesThe vehicle may have an ses lamp with any of the following DTC P06DA, P06DB, P06DC, P06B6, P06B7, P250A, P0300, P0340, P0341, P0335, P0336, P0641, P0011, P0010, P2088, P2089, and/or P2230. Possible crank no start or a stall. possible wiring jumper harness chaffed at the bolt at the X154 connector on lower left side of the frount cover.

CHEVROLET, GMC · 2017-10-01

Malfunction Indicator Lamp (MIL) Light On, Reduced Power Mode, DTC Set, Poor Performance/Shifts In rare cases, some customers may comment that the malfunction indicator lamp is on, poor performance and reduced power mode on. Technicians may find DTC P0641 or various others set. Not all of the effects listed may be experienced. However, the different effects and driver notifications may be caused by one of the wires in the ECM harness being chafed or cut. Due to the cause of the condition, and the positions of the wires in the harness, it is unlikely that more than one circuit will be affected by the condition. This condition may be caused by the ECM wiring harness rubbing on the ECM bracket. The harness may have chafing or damage to the wires. Contact with the edge of the bracket may…

BUICK, CADILLAC, CHEVROLET, GMC · 2016-11-18

This Preliminary Information communication provides information to the technician about vehicles that have a Check Engine Malfunction Indicator Lamp on. Technician will find Diagnostic Trouble Code P0641. Technician will need to unplug the fuel rail pressure sensor to see if that sensor is the cause of the five volt reference line being brought low. Technician should replace the fuel rail pressure sensor with current part available.

CHEVROLET, GMC · 2015-06-24

This Preliminary Information communication provides information to the technician the steps to diagnose and repair vehicles that have intermittent hard start Service Engine Soon Malfunction Indicator Lamp or low oil pressure lamp on. Technician may find Diagnostic Trouble Codes P0261, P0264, P0267, P0270, P0273, P0276, and or P0641. Technician should inspect the engine harness routing the Engine Control Module and the upper rear of the engine. Technician should repair and wires that are damaged from the harness rubbing. After the wires are repaired protective wrap, and reposition the harness away from the engine.

CHEVROLET · 2014-10-10

This Preliminary Information communication provides information to the technicians about vehicles that may have a Service Engine Soon Malfunction Indicator Lamp on. Technician may find Diagnostic Trouble Codes P069E, P0641, and B101D. Technician will need to inspect for wiring harness under the back seat twisted and pinched causing open circuits, shorts to ground, and shorts to other circuits in the harness.