P2127
2AZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P2120: Throttle / Pedal Position Sensor / Switch "D" Circuit
DTC P2120 - Throttle / Pedal Position Sensor / Switch "D" Circuit
DTC P2122 - Throttle / Pedal Position Sensor / Switch "D" Circuit Low Input
DTC P2123 - Throttle / Pedal Position Sensor / Switch "D" Circuit High Input
DTC P2125 - Throttle / Pedal Position Sensor / Switch "E" Circuit
DTC P2127 - Throttle / Pedal Position Sensor / Switch "E" Circuit Low Input
DTC P2128 - Throttle / Pedal Position Sensor / Switch "E" Circuit High Input
DTC P2138 - Throttle / Pedal Position Sensor / Switch "D" / "E" Voltage Correlation
DESCRIPTION
HINT: These DTCs relate to the Accelerator Pedal Position (APP) sensor.
This ETCS (Electronic Throttle Control System) does not use a throttle cable.
The Accelerator Pedal Position (APP) sensor is mounted on the accelerator pedal bracket and has 2 sensor circuits: VPA1 (main) and VPA2 (sub). The voltage, which is applied to terminals VPA1 and VPA2 of the ECM, varies between 0 V and 5 V in proportion to the operating angle of the accelerator pedal (throttle valve). A signal from VPA1 indicates the actual accelerator pedal opening angle (throttle valve opening angle) and is used for engine control. A signal from VPA2 conveys the status of the VPA1 circuit and is used to check the APP sensor itself.
The ECM monitors the actual accelerator pedal opening angle (throttle valve opening angle) through the signals from VPA1 and VPA2, and controls the throttle actuator according to these signals.
HINT: When any of these DTCs are set, check the APP sensor voltage by selecting the following menu items on the intelligent tester: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / ACCEL POS #1 and ACCEL POS #2.
HINT:
- Accelerator pedal positions are expressed as voltages.
- AP denotes for Accelerator Pedal.
MONITOR DESCRIPTION
When either of the voltage outputs of VPA1 or VPA2 deviates from the standard range, or the difference between the voltage outputs of the 2 sensor circuits is less than the threshold, the ECM determines that there is a malfunction in the APP sensor. The ECM then illuminates the MIL and sets a DTC.
Example:
When the voltage output of VPA1 drops below 0.4 V for more than 0.5 seconds while the accelerator pedal is being fully depressed, DTC P2122 is set.
If the malfunction is not repaired successfully, a DTC is set 2 seconds after the engine is next started.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
TYPICAL MALFUNCTION THRESHOLDS
P2120:
P2122:
P2123:
P2125:
P2127:
P2128:
P2138:
COMPONENT OPERATING RANGE
FAIL-SAFE
When any of DTCs P2120, P2121, P2122, P2123, P2125, P2127, P2128 and P2138 are set, the ECM enters fail-safe mode. If either of the 2 sensor circuits malfunctions, the ECM uses the remaining circuit to calculate the accelerator pedal position to allow the vehicle to continue driving. If both of the circuits malfunction, the ECM regards the accelerator pedal as being released. As a result, the throttle valve is closed and the engine idles.
Fail-safe mode continues until a pass condition is detected, and the ignition switch is turned off.
WIRING DIAGRAM
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.
PROCEDURE
1. READ VALUE USING INTELLIGENT TESTER (ACCEL POS #1 AND ACCEL POS #2)
(a) Connect the intelligent tester to the DLC3.
(b) Turn the ignition switch to the ON position and turn the tester on.
(c) Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / ACCEL POS #1 and ACCEL POS #2.
(d) Read the values displayed on the tester.
Standard voltage:
OK -- CHECK WHETHER DTC OUTPUT RECURS (ACCELERATOR PEDAL POSITION SENSOR DTCS)
NG -- Continue to next step.
2. INSPECT ACCELERATOR PEDAL ASSEMBLY (ACCELERATOR PEDAL POSITION SENSOR)
(a) Disconnect the A10 accelerator pedal position sensor connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:
NG -- REPLACE ACCELERATOR PEDAL ASSEMBLY
OK -- Continue to next step.
3. INSPECT ECM (VCPA AND VCP2 VOLTAGE)
(a) Turn the ignition switch to the ON position.
(b) Measure the voltage between the terminals of the E4 ECM connector.
Standard voltage:
NG -- REPLACE ECM
OK -- Continue to next step.
4. INSPECT ECM (VPA AND VPA2 VOLTAGE)
(a) Turn the ignition switch to the ON position.
(b) Measure the voltage according to the value(s) in the table below.
Standard voltage:
NG -- CHECK WIRE HARNESS (ECM - ACCELERATOR PEDAL POSITION SENSOR)
OK -- REPLACE ECM
5. CHECK WIRE HARNESS (ECM - ACCELERATOR PEDAL POSITION SENSOR)
(a) Disconnect the A10 acceleration pedal position sensor connector.
(b) Disconnect the E4 ECM connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
6. CHECK WHETHER DTC OUTPUT RECURS (ACCELERATOR PEDAL POSITION SENSOR DTCS)
(a) Connect the intelligent tester to the DLC3.
(b) Turn the ignition switch to the ON position and turn the tester on.
(c) Clear the DTCs DTC Check / Clear.
(d) Allow the engine to idle for 15 seconds.
(e) Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
(f) Read the DTCs.
Result:
B -- CHECK FOR INTERMITTENT PROBLEMS
A -- REPLACE ECM