HELP- -Code P0641 - reduced power
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Former Vendor
Joined: Dec 2010
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HELP- -Code P0641 - reduced power
This code P0641 is on my code reader -Reduced Power comes up on my display when started then if I try to drive it more codes will apear such as manifold absolute pressure,engine oil pressure,( Gauge will go to 0 when reved then back to 40 )fuel tank pressure,air conditioning refrigerant pressure,accelerator pedal position sens. I can clear the codes and somrtimes it will run great for 50 or so miles then the code problem will start and if it sets for over a hour this will come up. Has Anyone had this problem? Thanks in advance!
Tech Contributor
Joined: Dec 1999
Posts: 32,910
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
This is what the DTC references:
P0641 5-Volt Reference 1 Circuit ECM. The 5 VDC is the power source used to power ALL the sensors. 5 VDC gois in and the sensor output goes back to the ECU as a sensor signal.
Loosing that REF Voltage can be caused by numerous things. Things like:
- A shorted reference wire anywhere in the circuit.
- A bad sensor
- Bad ECU
You can examine ALL the sensors that are supplied by that reference voltage. CAREFULLY examine the connectors, the wiring and the wiring harness that the wires run thru. Look for damage wires or connectors.
When I get home I will pull up the DTC definition and troubleshooting guide and dig a little deeper. PM me your e-mail address and If I find a good picture or the schematics, I will send them to you.
BC
P0641 5-Volt Reference 1 Circuit ECM. The 5 VDC is the power source used to power ALL the sensors. 5 VDC gois in and the sensor output goes back to the ECU as a sensor signal.
Loosing that REF Voltage can be caused by numerous things. Things like:
- A shorted reference wire anywhere in the circuit.
- A bad sensor
- Bad ECU
You can examine ALL the sensors that are supplied by that reference voltage. CAREFULLY examine the connectors, the wiring and the wiring harness that the wires run thru. Look for damage wires or connectors.
When I get home I will pull up the DTC definition and troubleshooting guide and dig a little deeper. PM me your e-mail address and If I find a good picture or the schematics, I will send them to you.
BC
Pro
Joined: Sep 2012
Posts: 736
Likes: 22
From: Essexville MI
This code P0641 is on my code reader -Reduced Power comes up on my display when started then if I try to drive it more codes will apear such as manifold absolute pressure,engine oil pressure,( Gauge will go to 0 when reved then back to 40 )fuel tank pressure,air conditioning refrigerant pressure,accelerator pedal position sens. I can clear the codes and somrtimes it will run great for 50 or so miles then the code problem will start and if it sets for over a hour this will come up. Has Anyone had this problem? Thanks in advance!
