Circuit Description
The powertrain control module (PCM) provides a 5-volt reference to the following sensors:
| • | The throttle position (TP) sensor 2 |
| • | The accelerator pedal position (APP) sensor 1 |
| • | The manifold absolute pressure (MAP) sensor |
The PCM monitors voltage on the 5-volt reference circuit. If the voltage is higher or lower than required, DTC P0651 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 is unlock/accessory, run or crank position.
Conditions for Setting the DTC
| • | The PCM detects a voltage that is higher or lower than required on the 5-volt reference circuit. |
| • | The above condition is present for longer than 1 second. |
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | Clear the MIL and the DTC with a scan tool. |
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Powertrain Control Module Connector End Views or Engine Controls Connector End Views | ||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |
2 |
Important: If the vehicle has a cranks but will not run condition proceed to step 3. Did the DTC fail this ignition? | -- | Go to Step 3 | Go to Intermittent Conditions |
3 |
Is the voltage within the specified range? | 4.8-5.2 V | Go to Step 5 | Go to Step 4 |
4 | Is the voltage more than the specified value? | 5.2 V | Go to Step 8 | Go to Step 6 |
5 |
Is the voltage within the specified range? | 4.8-5.2 V | Go to Intermittent Conditions | Go to Step 9 |
6 |
Was a component replaced? | -- | Go to Step 12 | Go to Step 7 |
7 | Test this 5-volt reference circuit for a short to ground or for any sensor low reference circuit. Refer to Circuit Testing and Wiring Repairs . Did you find and correct a condition? | -- | Go to Step 12 | Go to Step 10 |
8 |
Did you find and correct a condition? | -- | Go to Step 12 | Go to Step 10 |
9 | Replace the throttle body assembly. Refer to Throttle Body Assembly Replacement . Did you complete the replacement? | -- | Go to Step 12 | -- |
10 | Test this 5-volt reference circuit for a short to the throttle actuator control (TAC) motor control 1 or 2 circuits. Did you find and correct a condition? | -- | Go to Step 12 | Go to Step 11 |
11 | Replace the powertrain control module (PCM). Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 12 | -- |
12 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 13 |
13 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK | |
