DTC P0651
DTC P0651: Sensor Reference Voltage B Malfunction
General Description
The powertrain control module (PCM) is equipped with a voltage monitor (5 V power source) to supply a stable 5 V to each sensor as reference voltage. The correct voltage for the sensors are loaded in the CPU of the PCM (A/D input) and when the sensor power voltage is a set value (high or low) for a certain time, the PCM detects a malfunction and stores a DTC.
Monitor Execution, Sequence, Duration, DTC Type
| Execution | Continuous |
| Sequence | None |
| Duration | 2.0 seconds or more |
| DTC Type | One drive cycle, MIL on |
Enable Conditions
| Condition | |
|---|---|
| Vehicle | ON mode |
Malfunction Threshold
The sensor power voltage is 6.00 V or more, or 3.99 V or less, for at least 2.0 seconds.
Possible Cause
- A/C pressure sensor VCC line short to power
- Accelerator pedal position (APP) sensor VCC line short to power
- EGR valve VCC line short to power
- Rocker arm oil pressure sensor VCC line short to power
- Camshaft position (CMP) sensor A VCC line short to power
- Camshaft position (CMP) sensor B VCC line short to power
- Transmission fluid pressure sensor VCC line short to power
- Fuel tank pressure sensor VCC line short to power
- A/C pressure sensor VCC line short to ground
- APP sensor A/B VCC line short to ground
- EGR valve VCC line short to ground
- Rocker arm oil pressure sensor VCC line short to ground
- CMP sensor A VCC line short to ground
- CMP sensor B VCC line short to ground
- Transmission fluid pressure sensor VCC line short to ground
- Fuel tank pressure sensor VCC line short to ground
- EVAP leak check module internal circuit failure
- PCM internal circuit failure
Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected, the MIL comes on and a Pending DTC, a Confirmed DTC, and the freeze data are stored in the PCM memory.
Conditions for clearing the DTC
The MIL is cleared if the malfunction does not return in three consecutive trips in which the diagnostic runs. The MIL, the Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the 12 volt battery.