DTC Troubleshooting: P0851
DTC P0851: Neutral Position Sensor A Circuit Low Voltage
NOTE: Before you troubleshoot, review the general troubleshooting information.

DTC Description
Confirmed DTC
Pending DTC
P0851 Neutral Position Sensor A Circuit Low Voltage
    

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
P0851 Neutral Position Sensor A Circuit Low Voltage
    

Is DTC P0851 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 neutral position sensor and the PCM. If the on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the on-board snapshot.?
2.
DTC check:

DTC check
?1.
Check for Pending or Confirmed DTCs with the HDS.
DTC Description
Confirmed DTC
Pending DTC
P0851 Neutral Position Sensor A Circuit Low Voltage
    
P1707 Neutral Position Sensor B Circuit Low Voltage
    

Are DTC P0851 and P1707 indicated at the same time?

     
YES
     
     
     
Go to step 3.
     
NO
     
     
     
Go to step 5.
3.
Determine possible failure area (neutral position sensor, others):

Determine possible failure area (neutral position sensor, others)
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
Disconnect the following connector.
Neutral position sensor 4P connector

?3.
Turn the vehicle to the ON mode.

?4.
Measure the voltage between test points 1 and 2.
Test condition
Vehicle ON mode
 
Neutral position sensor 4P connector: disconnected
Test point 1
Neutral position sensor 4P connector No. 1
Test point 2
Body ground


Is there about 5.0 V?

     
YES
     
     
     
     
NO
     
     
     
Go to step 4.
4.
Open wire check (VCC2 line):

Open wire check (VCC2 line)
?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 connector.
PCM connector E (80P)

?4.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
 
Neutral position sensor 4P connector: disconnected
 
PCM connector E (80P): disconnected
Test point 1
Neutral position sensor 4P connector No. 1
Test point 2
PCM connector E (80P) No. 77


Is there continuity?

     
YES
     
     
     
The VCC2 wire is OK. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM, then recheck. If DTC P0851 goes away and the PCM was substituted, replace the original PCM.?
     
NO
     
     
     
Repair an open in the VCC2 wire between the PCM (E77) and the neutral position sensor.?
5.
Determine possible failure area (neutral position sensor, others):

Determine possible failure area (neutral position sensor, others)
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
Disconnect the following connector.
Neutral position sensor 4P connector

?3.
Connect terminals A and B with a jumper wire.
Terminal A
Neutral position sensor 4P connector No. 1
Terminal B
Neutral position sensor 4P connector No. 3


?4.
Turn the vehicle to the ON mode.

?5.
Check the parameter(s) below with the HDS.
Signal
Current conditions
Values
Unit
Neutral Position Sensor 1
    

Is about 5.0 V indicated?

     
YES
     
     
     
     
NO
     
     
     
Go to step 6.
6.
Shorted wire check (NSS1 line):

Shorted wire check (NSS1 line)
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
Remove the jumper wire from the neutral position sensor 4P connector.

?3.
Jump the SCS line with the HDS, and wait more than 1 minute.


?4.
Disconnect the following connector.
PCM connector E (80P)

?5.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
 
Neutral position sensor 4P connector: disconnected
 
PCM connector E (80P): disconnected
Test point 1
Neutral position sensor 4P connector No. 3
Test point 2
Body ground


Is there continuity?

     
YES
     
     
     
Repair a short in the NSS1 wire between the PCM (E67) and the neutral position sensor.?
     
NO
     
     
     
The NSS1 wire is not shorted. Go to step 7.
7.
Open wire check (NSS1 line):

Open wire check (NSS1 line)
?1.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
 
Neutral position sensor 4P connector: disconnected
 
PCM connector E (80P): disconnected
Test point 1
Neutral position sensor 4P connector No. 3
Test point 2
PCM connector E (80P) No. 67


Is there continuity?

     
YES
     
     
     
The NSS1 wire is OK. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM, then recheck. If DTC P0851 goes away and the PCM was substituted, replace the original PCM.?
     
NO
     
     
     
Repair an open in the NSS1 wire between the PCM (E67) and the neutral position sensor.?