The powertrain control module (PCM) uses the 5-volt reference circuit as a sensor feed to the following sensors:
• | The manifold absolute pressure (MAP) |
• | The throttle position sensor 2 |
• | The accelerator pedal position sensor 1 |
The PCM monitors the voltage on the 5-volt reference circuit. If the voltage is out of tolerance, the PCM will set DTC P0651.
This diagnostic procedure supports the following DTC.
DTC P0651 5-volt reference 2 circuit
• | DTCs P0601, P0602, P0604, P0606, P1621, P2610 are not set. |
• | The ignition is on. |
• | The ignition voltage is greater than 5.2 volts. |
• | The PCM detects a voltage out of tolerance condition on the 5-volt reference circuit. |
• | The above condition is present for longer than 10 seconds. |
• | 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. |
• | 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 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | ||||
2 |
Did the DTC fail this ignition? | -- | Go to Step 3 | Go to Intermittent Conditions | ||||
3 | Visually and physically inspect the powertrain control module (PCM) and engine grounds. Ensure that the grounds are clean and secure. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 4 | ||||
4 |
Is the voltage near the specified value? | 5 V | Go to Step 6 | Go to Step 5 | ||||
5 | Is the voltage more than the specified value? | 5 V | Go to Step 9 | Go to Step 7 | ||||
6 |
Is the voltage near the specified value? | 5 V | Go to Intermittent Conditions | Go to Step 11 | ||||
7 |
Was a component replaced? | -- | Go to Step 12 | Go to Step 8 | ||||
8 | Test the 5-volt reference 2 circuits for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 10 | ||||
9 |
Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 10 | ||||
10 | Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | -- | Go to Step 12 | -- | ||||
11 | Replace the MAP sensor. Refer to Manifold Absolute Pressure Sensor Replacement . Did you complete the replacement? | -- | Go to Step 12 | -- | ||||
12 |
Did the DTC fail this ignition? | -- | Go to Step 3 | Go to Step 13 | ||||
13 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | System OK |