DTC P0121 Throttle / Pedal Position Sensor / Switch "A" Circuit Range / Performance Problem
HINT: This DTC relates to the Throttle Position (TP) sensor.
DESCRIPTION Refer to DTC P0120
DTC No. |
DTC Detection Condition |
Trouble Area |
P0121 |
Difference between VTA1 and VTA2 voltages less than 0.8 V, or more than 1.6 V for 2 seconds (1 trip detection logic) | TP sensor (built into throttle body) |
MONITOR DESCRIPTION
The ECM uses the TP sensor to monitor the throttle valve opening angle.
This sensor transmits two signals: VTA1 and VTA2. VTA1 is used to detect the throttle opening angle and VTA2 is used to detect malfunctions in VTA1. The ECM performs several checks to confirm the proper operation of the TP sensor and VTA1.
For each throttle opening angle, a specific voltage difference is expected between the outputs of VTA1 and VTA2. If the voltage output difference between the two signals deviates from the normal operating range, the ECM interprets this as a malfunction of the TP sensor. The ECM illuminates the MIL and sets the DTC.
If the malfunction is not repaired successfully, the DTC is set 2 seconds after the engine is next started.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
TYPICAL MALFUNCTION THRESHOLDS
FAIL-SAFE
When this DTC, as well as other DTCs relating to ETCS (Electronic Throttle Control System) malfunctions, is set, the ECM enters fail-safe mode. During fail-safe mode, the ECM cuts the current to the throttle actuator off, and the throttle valve is returned to a 6.5 throttle angle by the return spring. The ECM then adjusts the engine output by controlling the fuel injection (intermittent fuel-cut) and ignition timing, in accordance with the accelerator pedal opening angle, to allow the vehicle to continue at a minimal speed. If the accelerator pedal is depressed slowly, the vehicle can be driven slowly.
Fail-safe mode continues until a pass condition is detected, and the ignition switch is then turned off.
INSPECTION PROCEDURE
HINT: Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air-fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.
1 CHECK ANY OTHER DTC OUTPUT (IN ADDITION TO DTC P0121)
Result
HINT: If any DTCs other than P0121 are output, troubleshoot those DTCs first.
REPLACE THROTTLE BODY
Inspection
1. INSPECT VENTILATION VALVE
(a) Install a clean hose to the ventilation valve.
(b) Check the ventilation valve operation.
(1) Blow air into the cylinder head side, and check
that air passes through easily.
NOTICE:
Do not suck air through the valve.
Petroleum substances i ...
Removal
1. DISCHARGE FUEL SYSTEM PRESSURE
HINT:
See page FU-1.
2. DISCONNECT CABLE FROM NEGATIVE BATTERY
TERMINAL
3. REMOVE NO. 1 ENGINE UNDER COVER
4. DRAIN ENGINE COOLANT (See page CO-6)
5. REMOVE FRONT WIPER ARM HEAD CAP (See page
WW-4)
6. REMOVE FRONT WIPER ARM RH (See page WW-4)
7. REMOVE FRO ...
Installation
1. INSTALL REAR AXLE HUB & BEARING ASSEMBLY LH
(a) Install the hub & bearing assembly LH with the 4
bolts.
Torque: 56 N*m (571 kgf*cm, 41 ft.*lbf)
2. INSPECT BEARING BACKLASH (See page AH-19)
3. INSPECT AXLE HUB DEVIATION (See page AH-19)
4. INSTALL REAR DRIVE SHAFT ASSEMBLY LH (Se ...