P2135
2GR-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0120-P0123,P0220,P0222,P0223,P2135: Throttle / Pedal Position Sensor / Switch "A" Circuit
DESCRIPTION
HINT
This electrical throttle control system does not use a throttle cable.
The throttle position sensor is mounted on the throttle body, and detects the opening angle of the throttle valve. This sensor is a non-contact type, and uses Hall-effect elements, in order to yield accurate signals, even in extreme driving conditions, such as at high speeds as well as very low speeds.
The throttle position sensor has two sensor circuits which each transmits a signal, VTA1 and VTA2. VTA1 is used to detect the throttle valve angle and VTA2 is used to detect malfunctions in VTA1. The sensor signal voltages vary between 0 V and 5 V in proportion to the throttle valve opening angle, and are transmitted to the VTA terminals of the ECM.
As the valve closes, the sensor output voltage decreases and as the valve opens, the sensor output voltage increases. The ECM calculates the throttle valve opening angle according to these signals and controls the throttle actuator in response to driver inputs. These signals are also used in calculations such as air fuel ratio correction, power increase correction and fuel-cut control.
HINT
- When any of these DTCs are set, check the throttle valve opening angle by selecting the following menu items on the Techstream: Powertrain / Engine and ECT / Data List / ETCS / Throttle Sensor Position No. 1 and Throttle Sensor Position No. 2.
- Throttle Sensor Position No. 1 denotes the VTA1 signal (expressed in percentages), and Throttle Sensor Position No. 2 denotes the VTA2 signal (expressed in voltages).
Reference (Normal Condition)
MONITOR DESCRIPTION
P0120, P0122, P0123, P0220, P0222, P0223, P2135
The ECM uses the throttle position sensor to monitor the throttle valve opening angle. There are several checks that the ECM performs to confirm the proper operation of the throttle position sensor.
* A specific voltage difference is expected between the sensor terminals, VTA1 and VTA2, for each throttle valve opening angle. If the difference between VTA1 and VTA2 is incorrect, the ECM interprets this as a malfunction in the sensor, and sets a DTC.
* VTA1 and VTA2 each have a specific voltage range. If VTA1 or VTA2 is outside the normal operating range, the ECM interprets this as a malfunction in the sensor, and sets a DTC.
* VTA1 and VTA2 should never be close to the same voltage level. If VTA1 is within 0.02 V of VTA2, the ECM determines that there is a short circuit in the sensor, and sets a DTC.
If the malfunction is not repaired successfully, a DTC is set 2 seconds after the engine is next started.
P0121
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 throttle position 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 throttle position 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
P0120, P0122, P0123, P0220, P0222, P0223, P2135
P0121
TYPICAL MALFUNCTION THRESHOLDS
P0120:
P0121:
P0122:
P0123:
P0220:
P0222:
P0223:
P2135:
COMPONENT OPERATING RANGE
FAIL-SAFE
When any of these DTCs, as well as other DTCs relating to electronic throttle control system malfunctions, are 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° 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 turned off.
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT
- If other DTCs relating to different systems that have terminal E2 as the ground terminal are output simultaneously, terminal E2 may have an open circuit.
- Read freeze frame data using the Techstream. 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.
PROCEDURE
1. READ VALUE USING TECHSTREAM (THROTTLE POS AND THROTTLE POS #2)
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch on (IG) and turn the tester on.
(c) Select the following menu items: Powertrain / Engine and ECT / Data List / Throttle Position No. 1 and Throttle Sensor Position No. 2.
(d) Check the values displayed on the tester.
Result:
HINT
- DTC P0121 is stored when the voltages output from VTA1 and VTA2 are not consistent with the characteristics of the sensors. Therefore, check the Freeze Frame Data when this DTC is output. Use the following formula to confirm relative fluctuations in voltage.
Features of sensor output:
VTA2 x 0.8 is approximately equal to VTA1 + 1.11 V
VTA1: Throttle Position No. 1
VTA2: Throttle position No. 2
- If DTC P0121 is output, proceed to the "CHECK HARNESS AND CONNECTOR (THROTTLE POSITION SENSOR - ECM)".
B -- CHECK WHETHER DTC OUTPUT RECURS (THROTTLE POSITION SENSOR DTCS)
A -- Continue to next step.
2. CHECK HARNESS AND CONNECTOR (THROTTLE POSITION SENSOR - ECM)
(a) Disconnect the throttle body connector.
(b) Disconnect the ECM connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:
Check for open
Check for short
(d) Reconnect the throttle body connector.
(e) Reconnect the ECM connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (THROTTLE POSITION SENSOR - ECM)
OK -- Continue to next step.
3. INSPECT ECM (VC VOLTAGE)
(a) Turn the ignition switch on (IG).
(b) Measure the voltage according to the value(s) in the table below.
Standard voltage:
Text in Illustration
NG -- REPLACE ECM Components
OK -- Continue to next step.
4. REPLACE THROTTLE BODY
(a) Replace the throttle body Components.
NEXT -- Continue to next step.
5. CHECK WHETHER DTC OUTPUT RECURS (THROTTLE POSITION SENSOR DTCS)
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch on (IG) and turn the tester on.
(c) Clear the DTCs DTC Check / Clear.
(d) Start the engine.
(e) Allow the engine to idle for 15 seconds or more.
(f) Select the following menu items: Powertrain / Engine and ECT / Trouble Code.
(g) Read the DTCs.
Result:
B -- END
A -- REPLACE ECM Components