DTC P0121 THROTTLE/PEDAL POSITION SENSOR/SWITCH “A” CIRCUIT RANGE/PERFORMANCE

DTC P0121 THROTTLE/PEDAL POSITION SENSOR/SWITCH “A” CIRCUIT RANGE/PERFORMANCE

(1)	Rotor
(2)	Return spring
(3)	Voltage (V)
(4)	Throttle valve opening angle (°)

ENABLE CONDITION

Secondary Parameters	Enable Conditions
Engine coolant temperature	> 75°C (167°F)
Intake air temperature	> −10°C (14°F)
Atmospheric pressure	≥ 75.1 kPa (563 mmHg, 22.2 inHg)
Battery voltage	> 10.9 V
Fuel level	≥ 9 litres (2.38 US gal, 1.98 Imp gal)

GENERAL DRIVING CYCLE

Perform the diagnosis continuously after idling.

DIAGNOSTIC METHOD

Abnormality Judgment

Judge NG when one of the malfunctions below is completed such as Low malfunction (1), Low malfunction (2) and High malfunction.

Judgment Value

Malfunction Criteria	Threshold Value
Low malfunction (1): Judge NG when the continuous time of completing the malfunction criteria below becomes more than 10 seconds.
(Estimated value of throttle opening — output) throttle angle	≥ 20°
Engine speed	1,000 ←→ 3,200 rpm
Engine load (gn)	0.2 ←→ 1.0 g/rev
Intake air change during 0.5 engine rev.	< 0.01 g/rev
Manifold absolute pressure	< Atmosphere −6.67 kPa (−50 mmHg, −1.97 inHg)
Low malfunction (2): Judge NG when the continuous time of completing the malfunction criteria below becomes more than 10 seconds × 6 times.
Engine speed	≥ 1,600 rpm
Engine load (gn)	≥ 0.2 g/rev
Throttle opening	< 2°
Elapsed time after engine starting	≥ 5 seconds
High malfunction: Judge NG when the continuous time of completing the malfunction criteria below becomes more than 10 seconds.
(Output — estimated value of throttle opening) throttle angle	≥ 20°
Engine speed	1,000 ←→ 3,200 rpm
Engine load (gn)	0.2 ←→ 1.0 g/rev
Intake air change during 0.5 engine rev.	< 0.01 g/rev
Manifold absolute pressure	< Atmosphere −6.67 kPa (−50 mmHg, −1.97 inHg)

Estimated value of throttle opening: It is supposed from engine speed and engine load.

Time Needed for Diagnosis:

Low malfunction (1), High malfunction	10 seconds
Low malfunction (2)	10 seconds × 6 times.

Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cycles.

Normality Judgment

Judge OK and clear the NG when all of the malfunctions below are not completed such as Low malfunction (1), Low malfunction (2) and High malfunction.

Judgment Value

Malfunction Criteria	Threshold Value
Low malfunction (1): Judge OK when the continuous time of completing the malfunction criteria below becomes more than 3 seconds.
(Estimated value of throttle opening — output) throttle angle	< 20°
Engine speed	1,000 ←→ 3,200 rpm
Engine load (gn)	0.2 ←→ 1.0 g/rev
Intake air change during 0.5 engine rev.	< 0.01 g/rev
Manifold absolute pressure	< Atmosphere −6.67 kPa (−50 mmHg, −1.97 inHg)
Low malfunction (2): Judge OK when the malfunction criteria below are completed.
Throttle opening	≥ 2°
Elapsed time after engine starting	≥ 5 seconds
High malfunction: Judge OK when the continuous time of completing the malfunction criteria below becomes more than 3 seconds.
(Output — estimated value of throttle opening) throttle angle	< 20°
Engine speed	1,000 ←→ 3,200 rpm
Engine load (gn)	0.2 ←→ 1.0 g/rev
Intake air change during 0.5 engine rev.	< 0.01 g/rev
Manifold absolute pressure	< Atmosphere −6.67 kPa (−50 mmHg, −1.97 inHg)

DTC CLEAR CONDITION

•	When the OK idling cycle was completed 40 times in a row

•	When “Clear Memory” was performed

MALFUNCTION INDICATOR LIGHT CLEAR CONDITION

•	When the OK driving cycle was completed 3 times in a row

•	When “Clear Memory” was performed

FAIL SAFE

•	Throttle position sensor process: Fix the throttle opening at 6.4°.

•	ISC open loop compensation: Fix the amount of ISC open loop compensation at 5%.

•	ISC feedback compensation: Not allowed to calculate the amount of ISC feedback compensation.

ECM OPERATING AT DTC SETTING

Memorize the freeze frame data. (For test mode $02)