Discovery II
ENGINE MANAGEMENT SYSTEM - V8
DESCRIPTION AND OPERATION 18-2-29
In the event of a TP sensor signal failure any of the following symptoms may be observed:
l
Engine performance concern.
l
Delayed throttle response.
l
Failure of emission control.
l
Closed loop idle speed control inoperative.
l
Automatic gearbox kickdown inoperative.
l
Incorrect altitude adaptation.
l
MIL illuminated (NAS only).
There are three throttle position sensor diagnostic checks:
l
TP sensor signal is greater than the maximum threshold value – the engine speed must be greater than 400 rev/
min for longer than 2 seconds and the signal must be greater than 96% for longer than 50 ms.
l
TP sensor signal is less than the minimum threshold – the engine speed must be greater than 400 rev/min for
longer than 2 seconds and the signal must be less than 4% for longer than 50 ms.
l
Ratio of throttle position to mass of air flow – the calculated throttle angle must be outside limits when the engine
speed is between 800 rev/min and 4000 rev/min, the engine load is between 2 and 6.5 and the coolant
temperature is above -10
°
C (14
°
F).
Should a malfunction of the TP sensor occur the following fault codes may be evident and can be retrieved by
TestBook.
P code
J2012 description
Land Rover description
P0101
Mass or volume air flow circuit range/
performance problem
Load monitoring, the ratio of throttle position to air flow
P0122
TPS a circuit low input
Signal < minimum threshold
P0123
TPS a circuit high input
Signal > maximum threshold