DTC P0641, P0651, P0697 or P06A3 (ECM, LFW)
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DTC P0641, P0651, P0697 or P06A3 (ECM, LFW)
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DTC P0641
5 V Reference 1 Circuit
DTC P0651
5 V Reference 2 Circuit
DTC P0697
5 V Reference 3 Circuit
DTC P06A3
5 V Reference 4 Circuit
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Circuit/System Description
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The engine control module (ECM) has 4 internal 5 V reference circuits. Each internal reference circuit provides an external 5 V reference circuit for more than one sensor. A short to ground or short to voltage on one of the external 5 V reference circuits can affect all the components connected to the same internal 5 V reference circuit.
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Conditions for Running the DTC
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Ignition voltage is greater than 6.4 V.
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Reduced engine power is not active.
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DTCs P0641, P0651, P0697, P06A3 run continuously when the above conditions are met.
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Conditions for Setting the DTC
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The 5 V reference circuit voltage is greater or less than a predetermined threshold.
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Action Taken When the DTC Sets
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DTCs P0641, P0651, P0697, and P06A3 are Type A DTCs.
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Conditions for Clearing the DTC
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DTCs P0641, P0651, P0697, and P06A3 are Type A DTCs.
P0641
The 5 V reference 1 circuit provides 5 V to the following sensors:
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Fuel tank pressure (FTP) sensor
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Barometric pressure (BARO) sensor, throttle inlet absolute pressure sensor
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Fuel rail pressure (FRP) sensor
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A/C Refrigerant Pressure Sensor
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All four camshaft position sensors
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P0651
The 5 V reference 2 circuit provides 5 V to the crankshaft position sensor.
P0697
The 5 V reference 3 circuit provides 5 V to the following sensors:
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Manifold absolute pressure (MAP) sensor
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Accelerator pedal position sensor 2
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P06A3
The 5 V reference 4 circuit provides 5 V to the following sensors:
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Throttle position sensor
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Accelerator pedal position sensor 1
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It may be possible to locate the fault by disconnecting one component at a time from the 5 V reference circuit while viewing the 5 V Reference Circuit parameter on the scan tool. The scan tool parameter will change from Malfunction to OK when the source of the fault is disconnected. If all 5 V reference components have been disconnected and a fault is still indicated, the fault may exist in the wiring harness.
Schematic Reference
Engine Controls Schematics (3.0L (LF1))
Engine Controls Schematics (2.8L (LAU))
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
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Circuit/System Verification
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1.
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Ignition ON, check the diagnostic trouble code (DTC) information with a scan tool. DTC P0641, P0651, P0697, or P06A3 should not set.
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2.
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Note the scan tool's status parameters for the 5 V reference circuit. The parameter should show OK.
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3.
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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.
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1.
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Note
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Additional DTCs will set when disconnecting the components.
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Ignition OFF, disconnect the harness connector of all appropriate sensors for the applicable DTC. Refer to Diagnostic Aids.
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2.
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Ignition ON, test for 4.8-5.2 V between one of the affected 5 V reference circuits and ground.
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3.
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If the voltage is less than the specified range, test for a short to ground on the 5 V reference circuit for each affected component. If all circuits test normal, replace the K20 ECM.
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4.
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If the voltage is greater than the specified range, test for a short to voltage on the 5 V reference circuit for each affected component. If all circuits test normal, replace the K20 ECM.
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5.
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Note
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A short to voltage on the signal circuit of certain components may cause this DTC to set.
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Connect each component associated with the affected 5 V reference circuit one at a time while monitoring the appropriate scan tool 5 V Reference Circuit Status parameter. The parameter should continue to display OK.
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6.
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If the parameter displays Malfunction when a component is connected, test the signal circuit of that component for a short to voltage. If the circuit tests normal, replace the component.
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Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
