DTC Advanced Diagnostics: P0642, P0643 (3.0L Engine)
DTC P0642: Sensor Reference Voltage A Circuit Low Voltage DTC P0643: Sensor Reference Voltage A Circuit High Voltage
General Description
The powertrain control module (PCM) is equipped with a 5 V power supply circuit to supply a stable 5 V to each sensor as reference voltage. The correct voltage for the sensors are loaded in the microcomputer (MCU) of the PCM (A/D input). If the sensor power voltage is a set value for a certain time, the PCM detects a malfunction and stores a DTC.
Monitor Execution, Sequence, Duration, DTC Type
| Execution | Continuous |
| Sequence | None |
| Duration | 0.5 second or more |
| DTC Type | One drive cycle, MIL on |
Enable Conditions
| Condition | |
|---|---|
| Vehicle | ON mode |
Malfunction Threshold
DTC: P0642
The sensor power voltage is less than 2.3145 V for at least 0.5 second.
DTC: P0643
The sensor power voltage is more than 2.686 V for at least 0.5 second.
Possible Cause
DTC: P0642
- Crankshaft position (CKP) sensor VCC line short to ground
- Manifold absolute pressure (MAP) sensor VCC line short to ground
- Fuel rail pressure sensor VCC line short to ground
- Engine oil pressure sensor VCC line short to ground
- Turbocharger wastegate control actuator position sensor VCC line short to ground
- Throttle body VCC line short to ground
- Accelerator pedal position (APP) sensor VCC line short to ground
DTC: P0643
- CKP sensor VCC line short to power
- MAP sensor VCC line short to power
- Fuel rail pressure sensor VCC line short to power
- Engine oil pressure sensor VCC line short to power
- Turbocharger wastegate control actuator position sensor VCC line short to power
- Throttle body VCC line short to power
- APP sensor VCC line short to power
Common
- 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, the freeze data, and the on-board snapshot 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, the freeze data, and the on-board snapshot can be cleared with the scan tool clear command.