Toyota Corolla Repair Manual: Circuit description
Refer to dtc p0120
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Dtc no. |
Dtc detection condition |
Trouble area |
| P0121 | The following condition is met 4 times. After the vehicle speed has exceeded 19 mph (30 km/h) once, the throttle position sensor output value is out of normal range when the throttle valve is closed at 0 km/h |
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Monitor description
The throttle position sensor varies its resistance with the angle of the throttle valve. The ecm applies a regulated reference voltage to the throttle position sensor “+” terminal and calculates the angle of the throttle valve based on the voltage present at the throttle position sensor “signal” terminal.
When the throttle valve is near the fully closed position, the output voltage of the throttle position sensor is low. When it is near the fully open position, the output voltage is high.
The ecm checks the indicated angle of the throttle valve during “stop and go” conditions. If the indicated angle (or voltage) in the “closed throttle” position is out of the specified range, the ecm interprets this as a malfunction in the throttle position sensor and sets a dtc.
Monitor strategy
Typical enabling condition
”Stop and go” is defined as follows: ”stop” indicates a vehicle speed of 0 mph (0 km/h). ”Go” indicates a vehicle speed of 18.6 Mph (30 km/h).
Typical malfunction thresholds
Component operating range
Throttle/pedal position
sensor/switch ”a” circuit
range/performance problem
Dtc p0121 throttle/pedal position
sensor/switch ”a” circuit
range/performance problem
Hint:
this is the purpose of the ”throttle position sensor”. ...
Inspection procedure
Hint:
read freeze frame data using the hand-held tester or the obd ii scan tool.
Freeze frame data records the
engine conditions when a malfunction is detected. When troubleshooting, it is
usefu ...
Other materials:
On–vehicle inspection
1. Install lspv gauge (sst) and bleed air
remove the bleeder plugs from the front and rear brake cylinder.
install the lspv gauge (sst), and bleed the air.
Sst 09709–29018
2. Raise master cylinder pressure and check rear wheel cylinder pressure
Hint:
when inspecting ...
Adjustment
1. Inspect and adjust clutch pedal sub–assy
Turn over the floor carpet.
check that the pedal height is correct.
Pedal height from asphalt sheet:
135.8 – 145.8 Mm (5.346 – 5.740 In.)
adjust the pedal height.
Loosen the lock nut and turn the stopper bolt until
the h ...
Inspection procedure
Hint:
hand–held tester only:
narrowing down the trouble area is possible by performing ”a/f control” active
test (heated oxygen
sensor or other trouble areas can be distinguished).
Perform active test using hand–held tester (a/f control).
Hint:
”a/f control” is the active test which cha ...