DTC P0641
Diagnostic Instructions
DTC Descriptor
DTC P0641 00: 5V Reference 1 Circuit
Malfunction
Circuit/System Description
The engine control module (ECM) has three 5 V reference
circuits. The ECM provides the 5 V reference to various
sensors. Each reference circuit provides a 5-volt reference for
more than one sensor. A short to ground or voltage on one of the
5-volt reference circuits will affect all components connected to
that 5 V reference circuit. The ECM monitors the voltage on
the 5 V reference circuits.
Conditions for Running the DTC
• |
The DTCs run continuously when the above condition
is met. |
Conditions for Setting the DTC
The control module detects a voltage above 5.5 V or below
4.5 V on any of the 5-volt reference circuits for greater than
0.5 s.
Action Taken When the DTC Sets
• |
DTC P0641 is a Type B DTC. |
• |
The ECM commands the throttle actuator control
(TAC) system to operate in a Reduced Engine Power mode. |
Conditions for Clearing the DTC
DTC P0641 is a Type B DTC.
Diagnostic Aids
If a shared 5 V reference circuit is shorted to ground or
shorted to a voltage, other 5 V reference circuits may be
affected.
P0641
The 5-volt reference 1 circuit provides 5 V to the
accelerator pedal position (APP) sensor 2, A/C refrigerant
pressure sensor, throttle position sensor, exhaust gas
recirculation (EGR) valve, turbocharger vane position sensor,
clutch pedal position (CPP) sensor and diesel particulate filter
pressure sensor
Reference Information
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Ignition ON, observe the DTC information with a scan
tool. DTC P0641 should not set.
- Operate the vehicle within the Conditions for Running
the DTC to verify the DTC does not reset. You may also operate the
vehicle within the conditions that you observed from the Freeze
Frame/Failure Records data.
Circuit/System Testing
Note: Additional DTCs will set
when disconnecting the components.
- Ignition OFF, disconnect the harness connector at all
appropriate sensors for the applicable DTC. Refer to Diagnostic
Aids.
- Ignition ON, test for 4.6-5.4 V between the
5 V reference circuit and ground.
⇒ |
If the voltage is less than the specified range,
test the 5 V reference circuit for a short to ground. If all
circuits test normal, replace the K20 Engine Control
Module. |
⇒ |
If greater than the specified range, test the
5 V reference circuit for each component associated with the
5 V reference circuit for a short to voltage. If all circuits
test normal, replace the K20 Engine Control Module. |
Note: A short to voltage on the
signal circuit of certain components may cause this DTC to
set.
- Observe the scan tool that DTC P0641 is not set
while connecting each component associated with the 5 V
reference circuit one at a time.
⇒ |
If the DTC set when a component is connected, test
the signal circuit for a short to voltage. If all circuits test
normal, replace the component. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
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