Q: 2008 chevy malibu code p0641

asked by on March 04, 2018

the code p0641

My car has 171000 miles.
My car has an automatic transmission.

Battery is dead Inspection $79.99 - $89.99 Get a Quote
Check Engine Light is on Inspection $79.99 - $89.99 Get a Quote

There are two 5 volt reference circuits for vehicle sensors (denoted circuit 1 and 2) each of which are monitored by the vehicle computer. When the code P0614 sets that means that the voltage on Circuit No. 1 is out of range (too far off from the nominal 5 volts), high or low. Typically, this is due to either a wiring fault (short, high resistance, etc.) but it can also be caused by an internally shorted sensor. Check your battery first though. A faulty battery will cause out of range voltages (on the low side, of course) and potentially set codes. On your car, the No. 1 five volt reference circuit supplies the manifold absolute pressure (MAP) sensor, the fuel tank pressure (FTP) sensor, the air conditioning (A/C) refrigerant pressure sensor, the accelerator pedal position (APP) sensor No. 2, and the intake camshaft position (CMP) sensor (this list should be confirmed with the wiring diagram prior to diagnostics). If it is a sensor issue (versus a wiring fault), unplugging sensors, one at a time, will show a large voltage change on the reference circuit as the circuit voltage is monitored on a scan tool and that can help narrow the diagnostic. As necessary, circuit wiring integrity must be checked, too. Typically, you will need to have in hand the factory wiring diagram from the Shop Manual to perform the required circuit traces. If you desire a speedy resolution, you can just request a Check Engine Light diagnostic and the responding certified mechanic will get the code resolved for you at your location. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

What others are asking

Oil leak

The only sensor I am aware of that is above the a/c compressor on that side of the motor is the camshaft sensor located just above the compressor in the cylinder head. It has an O-ring that can leak oil...

Drive belt loose and power steering not working.

Hello, thank you for writing in. The vehicle's drive belt is kept tight with an "auto-tensioner". This may be the pulley that has "popped" and released the tension. If that was the case, you would likely notice more issues than...

What causes an integrated supply module to burn out?

Congratulations - you have gotten 190K out of your module! This module is mounted under the passenger side cabin filter in the engine compartment - a very hot place to exist. The most common failure source on these modules is...

Whining noise in my 2008 Mitsubishi Lancer's CVT Transmission

Check the transmission fluid level and condition. The oil cooler can fail, causing loss of enough fluid to cause noise from the transmission. There is a manufacturer Technical Service Bulletin relative to parts failure in the transmission accompanied by a...

Grinding noise of the engine with P0340 code

Code P0340 is a camshaft sensor fault. The cam sensor is responsible not only for determining cam position, but it also is used by the engine computer for cylinder identification to set up both ignition firing sequence and sequential injection...

Oil Change timing

Your vehicle has an on board, computerized oil life indicator system. When the system determines that an oil change is actually needed, the oil life indicator will provide a maintenance message (see your Owner's Manual for further and complete details)....

My truck turns over but won't start.

When a truck won't start, it's usually going to be an ignition or fuel system-related malfunction. The fact that your gas gauge was "ticking" a bit may be an indicator that an electrical problem exists, causing the ignition system to...

ABS and Traction lights on

These lights indicate a fault in either the Anti-lock Brake System and/or Traction Control System. In my experience, when these two lights come on together, it is usually caused by a faulty wheel speed sensor. However, it could also be...

Power train light

Hi There, Code P1450 relates to the EVAP system in your vehicle and us unrelated to the power train malfunction you are referring to. Your car has a small purge valve with a purge solenoid in the Evaporative Emissions system...

Related articles

The Best Used Cars to Buy If You're a Carpenter
If If you're a carpenter, and working for someone else, the best used car is whatever you like that gets you to work on time and holds your tools – in short, practically any used car will do. If you...
2012 Chevrolet Equinox vs. 2012 GMC Terrain: Which One Should I Buy?
The mid-size crossover SUV category offers the comfort and size of an SUV, but on the platform of a car, giving it the look and feel of a large hatchback. The unibody construction typical of passenger vehicles is used instead...
2012 Chevrolet Cruze vs. 2012 Hyundai Elantra: Which One Should I Buy?
When you’re looking for a four-door sedan, you’re likely interested in a smaller family car that still offers decent styling and looks, great gas mileage, and a comfortable interior that will keep your family safe as you’re driving. While not...