Circuit Description
The engine control module (ECM) provides 5-volt reference voltage through the reference circuit 2 to the accelerator pedal position sensor. The ECM monitors the voltage on the 5-volt reference 2 circuit. If the ECM detects that the voltage is out of tolerance, this DTC will set.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0651 5-Volt Reference 2 Circuit
Conditions for Running the DTC
| • | The ignition switch is ON. |
| • | The battery voltage is between 10-16 volts. |
Conditions for Setting the DTC
When the 5-volt reference circuit 2 voltage is more than 5.5 volts or less than 4.5 volts.
Action Taken When the DTC Sets
| • | The ECM illuminates the malfunction indicator lamp (MIL) and reduced engine power indicator lamp, if fitted, when the diagnostic runs and fails. |
| • | The ECM records the operating conditions at the time the diagnostic fails. The ECM stores this information in the Failure Records. |
Conditions for Clearing the DTC
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | Clear the MIL and the DTC with a scan tool. |
Diagnostic Aids
If an intermittent condition is suspected, the following may cause an intermittent:
| • | Poor connections |
| • | Misrouted harness |
| • | Rubbed through wire insulation |
| • | Broken wire inside the insulation |
Inspect for the following conditions:
| • | Poor connection at ECM--Inspect harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection. |
| • | Damaged harness--Inspect the wiring harness for damage. If the harness appears to be OK, observe the DTC P0651 display on the scan tool while moving the connectors and wiring harness related to the sensor. A change in the display will indicate the location of the fault. |
Step | Action | Values | Yes | No | ||||
|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | ||||||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |||||
2 |
Does the DTC fail this ignition? | -- | Go to Step 3 | Go to Diagnostic Aids | ||||
3 |
Is the APP Sensor 2 parameter within the specified range? | 4.5-5.5 V | Go to Step 5 | Go to Step 4 | ||||
4 |
Did you find and correct the condition? | -- | Go to Step 8 | Go to Step 6 | ||||
5 | Replace the APP sensor. Refer to Accelerator Pedal Position Sensor Replacement . Did you complete the replacement? | -- | Go to Step 8 | -- | ||||
6 |
Did you find and correct the condition? | -- | Go to Step 8 | Go to Step 7 | ||||
7 |
Important: The replacement ECM must be programmed. Replace the ECM. Refer to Engine Control Module Programming and Setup , Engine Control Module Replacement/Restore Fuel Rate Data , and Fuel Injector Flow Rate Programming . Did you complete the replacement? | -- | Go to Step 8 | -- | ||||
8 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 9 | ||||
9 | Observe the stored information, Capture Info with a scan tool. Are there any DTCs that you have not diagnosed? | -- | System OK | |||||
