Subaru 2009 IMPREZA, Service Manual

Page: 1754 / 3619

GD(H4DOTC)-166
Diagnostic Trouble Code (DTC) Detecting Criteria
GENERAL DESCRIPTION
CJ:DTC P0851 NEUTRAL SWITCH INPUT CIRCUIT LOW (MT MODEL)
1. OUTLINE OF DIAGNOSIS
Judge the open or short circuit of the neutral SW.
Judge as NG when there is no change in the neutral SW even if the driving shift was applied. (There is neutral
SW ON/OFF inversion from the vehicle speed and engine speed.)
2. ENABLE CONDITIONS
3. GENERAL DRIVING CYCLE
Perform the diagnosis continuously in 2 seconds after starting the engine.
4. DIAGNOSTIC METHOD
• Abnormality Judgement
Judge NG when the malfunction criteria below are completed determined times or more after the neutral SW
change.
Time Needed for Diagnosis: 3 time(s)
Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cy-
cles.
• Normality Judgement
Judge as OK and clear NG when there is change in the neutral SW.
Time Needed for Diagnosis: Less than 1 second
Secondary Parameters Enable Condition
Battery voltage
t
10.9 V
Starter relay OFF
Judgement Value
Malfunction Criteria Threshold Value
Neutral switch signal (while changing
from a to b below) LOW (ON) continues.
Driving condition change From a) to b)
a) Engine speed 600 rpm — 900 rpm &
Vehicle speed = 0 km/h (0 MPH)
b) Engine speed 1600 rpm — 2550 rpm
& Vehicle speed
t
64 km/h (39.8 MPH)
Judgement Value
Malfunction Criteria Threshold Value
Neutral switch signal (while changing
from a to b below) Changes to HIGH
(OFF).
Driving condition change From a) to b)
a) Engine speed 600 rpm — 900 rpm &
Vehicle speed = 0 km/h (0 MPH)
b) Engine speed 1600 rpm — 2550 rpm
& Vehicle speed
t
64 km/h (39.8 MPH)