DTC P0641: Sensor Reference Voltage A Malfunction

NOTE:  Before you troubleshoot, review the general troubleshooting information - Refer to: How to Troubleshoot the Fuel and Emissions SystemsHow to Troubleshoot the CVT System(CVT System) .

• 1. Problem verification:

  1. Turn the vehicle to the ON mode.

  2. Clear the DTC with the HDS.

  3. Check for Pending or Confirmed DTCs with the HDS.

  DTC Description	Confirmed DTC	Pending DTC	Freeze Frame
  P0641 Sensor Reference Voltage A Malfunction

  Is DTC P0641 indicated?

  YES 

  The failure is duplicated. Go to step 2.

  NO 

  Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the PCM and these parts. If the freeze data/on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the freeze data/on-board snapshot.

  • MAP sensor
  • Fuel rail pressure sensor
  • CVT drive pulley speed sensor
  • APP sensor
  • A/C pressure sensor
  • FTP sensor (USA and Canada models)
• 2. Determine possible failure area (VCC lines, others):

  1. Turn the vehicle to the OFF (LOCK) mode.

  2. Disconnect the following connectors.

  MAP sensor 3P connector

  Fuel rail pressure sensor 3P connector

  CVT drive pulley speed sensor 3P connector

  APP sensor 6P connector

  A/C pressure sensor 3P connector

  FTP sensor 3P connector (USA and Canada models)

  3. Turn the vehicle to the ON mode.

  4. Clear the DTC with the HDS.

  5. Check for Pending or Confirmed DTCs with the HDS.

  DTC Description	Confirmed DTC	Pending DTC	Freeze Frame
  P0641 Sensor Reference Voltage A Malfunction

  Is DTC P0641 indicated?

  YES 

  Go to step 4.

  NO 

  Go to step 3.

• 3. Shorted part check:

  1. Check for Pending or Confirmed DTCs with the HDS while reconnecting these parts, one at a time:

  • MAP sensor
  • Fuel rail pressure sensor
  • CVT drive pulley speed sensor
  • APP sensor
  • A/C pressure sensor
  • FTP sensor (USA and Canada models)

  DTC Description	Confirmed DTC	Pending DTC	Freeze Frame
  P0641 Sensor Reference Voltage A Malfunction

  Is DTC P0641 indicated?

  YES 

  Replace the part that caused the DTC when it was reconnected.

  NO 

  Check for poor connections or loose terminals at the PCM and the following parts, then go to step 1.

  • MAP sensor
  • Fuel rail pressure sensor
  • CVT drive pulley speed sensor
  • APP sensor
  • A/C pressure sensor
  • FTP sensor (USA and Canada models)
• 4. Shorted wire check (VCC lines):

  1. Turn the vehicle to the OFF (LOCK) mode.

  2. Jump the SCS line with the HDS, and wait more than 1 minute.

  3. Disconnect the following connectors.

  PCM connector A (51P)

  PCM connector C (51P)

  4. Check for continuity between these test points and body ground individually.

  Test condition	Vehicle OFF (LOCK) mode
  	MAP sensor 3P connector: disconnected
  	Fuel rail pressure sensor 3P connector: disconnected
  	CVT drive pulley speed sensor 3P connector: disconnected
  	APP sensor 6P connector: disconnected
  	A/C pressure sensor 3P connector: disconnected
  	FTP sensor 3P connector (USA and Canada models): disconnected
  	PCM connector A (51P): disconnected
  	PCM connector C (51P): disconnected

  Connector	Terminal
  PCM connector A (51P)	No. 29 and No. 31
  PCM connector C (51P)	No. 41

  Is there continuity?

  YES 

  Repair a short in the VCC wire between the PCM (A29, A31, or C41) and each part that was disconnected in step 2.

  NO 

  The VCC wires are OK. Update the PCM if it does not have the latest software, or substitute a known-good PCM , then recheck. If DTC P0641 goes away and the PCM was updated, troubleshooting is complete. If DTC P0641 goes away and the PCM was substituted, replace the original PCM .