| DTC Code | DTC Name |
|---|---|
| P0120 | Throttle / Pedal Position Sensor / Switch "A" Circuit Malfunction |
| P0121 | Throttle / Pedal Position Sensor / Switch "A" Circuit Range / Performance Problem |
| P0122 | Throttle / Pedal Position Sensor / Switch "A" Circuit Low Input |
| P0123 | Throttle / Pedal Position Sensor / Switch "A" Circuit High Input |
| P0220 | Throttle / Pedal Position Sensor / Switch "B" Circuit |
| P0222 | Throttle / Pedal Position Sensor / Switch "B" Circuit Low Input |
| P0223 | Throttle / Pedal Position Sensor / Switch "B" Circuit High Input |
| P2135 | Throttle / Pedal Position Sensor / Switch "A" / "B" Voltage Correlation |
DESCRIPTION
This ETCS (Electronic Throttle Control System) does not use a throttle cable.
The Throttle Position (TP) 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 TP sensor has two sensor circuits, each of which 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 VTA1 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.
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P0120 | Output voltage of VTA1 quickly fluctuates beyond lower and upper malfunction thresholds for 2 seconds (1 trip detection logic) |
|
| P0121 | Difference between VTA and VTA2 voltages less than 0.8 V, or more than 1.6 V for 2 seconds (1 trip detection logic) |
|
| P0122 | Output voltage of VTA1 0.2 V or less for 2 seconds (1 trip detection logic) |
|
| P0123 | Output voltage of VTA1 4.535 V or more for 2 seconds (1 trip detection logic) |
|
| P0220 | Output voltage of VTA2 quickly fluctuates beyond lower and upper malfunction thresholds for 2 seconds (1 trip detection logic) |
|
| P0222 | Output voltage of VTA2 1.75 V or less for 2 seconds (1 trip detection logic) |
|
| P0223 | Output voltage of VTA2 4.8 V or more, and VTA1 between 0.2 V and 2.02 V, for 2 seconds (1 trip detection logic) |
|
| P2135 | Either condition (a) or (b) is met (1 trip detection logic): (a) Difference between output voltages of VTA1 and VTA2 0.02 V or less for 0.5 seconds or more (b) Output voltage of VTA1 0.2 V or less, and VTA2 1.75 V or less, for 0.4 seconds or more |
|
MONITOR DESCRIPTION
The ECM uses the Throttle Position (TP) sensor to monitor the throttle valve opening angle. There are several checks that the ECM performs to confirm the proper operation of the TP 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.
FAIL-SAFE
When any of these DTCs, as well as other DTCs relating to ETCS (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, and the throttle valve is returned to a 7° 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 firmly and gently, the vehicle can be driven slowly.
Fail-safe mode continues until a pass condition is detected, and the power switch is then turned off.
INSPECTION PROCEDURE
If other DTCs relating to different systems that have terminal ETA as the ground terminal are output simultaneously, terminal ETA may have an open circuit.
Read freeze frame data using the intelligent tester. Freeze frame data records the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.
PROCEDURE
CHECK HARNESS AND CONNECTOR (THROTTLE POSITION SENSOR - ECM)
Disconnect the E21 throttle body connector.
Disconnect the E2 ECM connector.
Measure the resistance according to the value(s) in the table below.
| Standard resistance (Check for open) | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
| Standard resistance (Check for short) | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
INSPECT ECM (VC VOLTAGE)
Disconnect the E21 throttle body connector.
Measure the voltage according to the value(s) in the table below.
| Standard voltage | ||||||
|---|---|---|---|---|---|---|
|
REPLACE THROTTLE BODY
Replace the throttle body (see pageClick here).
CHECK WHETHER DTC OUTPUT RECURS (THROTTLE POSITION SENSOR DTCS)
Connect the intelligent tester to the DLC3.
Turn the power switch on (IG).
Turn the tester ON.
Clear DTCs (see pageClick here).
Turn the power switch off and wait for at least 30 seconds.
Turn the power switch on (IG) and turn the intelligent tester ON.
Put the engine in inspection mode (Click here).
Allow the engine to idle for 15 seconds or more.
Enter the following menus: Powertrain / Engine and ECT / DTC.
Read DTCs.
| Display (DTC Output) | Proceed to |
|---|---|
| P0120, P0121, P0122, P0123, P0220, P0222, P0223, and/or P2135 | A |
| No output | B |
REPAIR OR REPLACE HARNESS OR CONNECTOR
REPLACE ECMClick here
SYSTEM OK
REPLACE ECMClick here