DTC Advanced Diagnostics: P0850
DTC P0850:Neutral Position Sensor A/B Incorrect Voltage Correlation

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 variance of both sensor signals neutral position sensor A and neutral position sensor B are compared with the synchronization tolerance. If the variance of the neutral position sensors 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
Minimum
Maximum
Neutral position sensor A output voltage [Neutral Position Sensor 1]
0.49 V
4.03 V
Neutral position sensor B output voltage [Neutral Position Sensor 2]
0.24 V
3.26 V

Malfunction Threshold
The variance of both sensor signals (absolute difference between signal voltage of neutral position sensor A multiplicated by correction factor and signal voltage of neutral position sensor B) is greater than 0.17 - 0.62 V for at least 0.5 second.

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.
Neutral position sensor A NSS1 line short to neutral position sensor B NSS2 line
Neutral position sensor A failure
Neutral position sensor B 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.