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 V reference for more than one
sensor. A short to ground or voltage on one of the 5 V 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 V 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 V 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
| 1. |
Ignition ON, observe the DTC
information with a scan tool. DTC P0641 should not set.
|
| 2. |
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.
|
| 1. |
Ignition OFF, disconnect the
harness connector at all appropriate sensors for the applicable
DTC. Refer to Diagnostic Aids. |
| 2. |
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.
|
| 3. |
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.
|
