DTC Advanced Diagnostics: P0851, P0852
DTC P0851:Neutral Position Sensor A Circuit Low Voltage
DTC P0852:Neutral Position Sensor A Circuit High Voltage

General Description

The powertrain control module (PCM) monitors neutral position sensors for electrical malfunctions. The function is checking if the gear is in the neutral position or not. In order to provide diagnostics, the neutral position sensor A output voltage is continuously monitored and compared with minimum and maximum thresholds. If the neutral position sensor A output voltage is a specified value, 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 off

Enable Conditions
Condition
 
Vehicle
ON mode

Malfunction Threshold
DTC: P0851

The neutral position sensor A output voltage [Neutral Position Sensor 1] is less than 0.49 V for at least 0.5 second.

DTC: P0852

The neutral position sensor A output voltage [Neutral Position Sensor 1] is greater than 4.0306 V for at least 0.5 second.

[ ]: HDS Parameter

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.
DTC: P0851
Neutral position sensor A VCC line open
Neutral position sensor A NSS1 line short to ground
Neutral position sensor A NSS1 line open

DTC: P0852
Neutral position sensor A NSS1 line short to power
Neutral position sensor A SG line open

Common
Neutral position sensor A failure
PCM internal circuit failure

Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected, a Pending DTC, a Confirmed DTC, and the freeze data are stored in the PCM memory. The MIL does not come on.

Conditions for clearing the DTC
The Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command.