DTC P0651 — LNP or LNQ
Diagnostic Instructions
DTC Descriptor
DTC P0651 00: 5V Reference 2 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 greater 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 ECM 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 P0651 00 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 P0651 00 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.
P0651 00
The 5 V reference 2 circuit provides 5 V to the accelerator pedal position (APP) sensor 2, A/C pressure sensor, diesel particle filter differential pressure sensor, manifold absolute pressure sensor and the intake manifold runner position 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 P0651 00 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 P0651 00 is not set while connecting each component associated with the 5 V reference circuit one at a time.
⇒ | If the DTC sets 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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