DTC Troubleshooting: P0641
DTC P0641: Sensor Reference Voltage A Malfunction
NOTE: Before you troubleshoot, review the general troubleshooting information.

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

1.
Problem verification:

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
Output shaft (countershaft) speed sensor (M/T model)
CVT input shaft (drive pulley) speed sensor (CVT model)
APP sensor
2.
Determine possible failure area (VCC lines, others):

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
Output shaft speed sensor 3P connector (M/T model)
CVT input shaft (drive pulley) speed sensor 3P connector (CVT model)
APP sensor 6P connector

?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:

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
Output shaft (countershaft) speed sensor (M/T model)
CVT input shaft (drive pulley) speed sensor (CVT model)
APP sensor

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
Output shaft (countershaft) speed sensor (M/T model)
CVT input shaft (drive pulley) speed sensor (CVT model)
APP sensor
4.
Shorted wire check (VCC lines):

Shorted wire check (VCC lines)
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
Jump the SCS line with the HDS.


?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
Output shaft speed sensor 3P connector: disconnected (M/T model)
CVT input shaft (drive pulley) speed sensor 3P connector: disconnected (CVT model)
APP sensor 6P connector: disconnected
PCM connector A (51P): disconnected
PCM connector C (51P): disconnected

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

Is there continuity?

     
YES
     
     
     
Repair a short in the VCC wire between the PCM (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.?