DTC Advanced Diagnostics: P0641

DTC P0641:Sensor Reference Voltage A 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, OBD Status

Execution	Continuous
Sequence	None
Duration	2.0 seconds or more
DTC Type	One drive cycle, MIL on
OBD Status	PASSED/FAILED/NOT COMPLETED (STILL TESTING)

Enable Conditions

Condition
Vehicle	ON mode

Malfunction Threshold

The sensor power voltage is 5.2 V or more, or 4.5 V or less, for at least 2.0 seconds.

Possible Cause

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.

	Manifold absolute pressure (MAP) sensor VCC line short to power
	Fuel rail pressure sensor VCC line short to power
	Output shaft (countershaft) speed sensor VCC line short to power^*1
	CVT drive pulley speed sensor VCC line short to power^*2
	Accelerator pedal position (APP) sensor VCC line short to power
	MAP sensor VCC line short to ground
	Fuel rail pressure sensor VCC line short to ground
	Output shaft (countershaft) speed sensor VCC line short to ground^*1
	CVT drive pulley speed sensor VCC line short to ground^*2
	APP sensor VCC line short to ground
	PCM internal circuit failure

*1: M/T model

*2: CVT model

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.