P0122
DTC P0122 THROTTLE/PEDAL POSITION CIRCUIT LOW INPUTComponent Location:
GENERAL DESCRIPTION
The Throttle Position Sensor (TPS) is mounted on the throttle body and detects the opening angle of the throttle plate. The TPS has a variable resistor (potentiometer) whose characteristic is the resistance changing according to the throttle angle. During acceleration, the TPS resistance between the reference 5 V and the signal terminal decreases and output voltage increases; during deceleration, the TPS resistance increases and TPS output voltage decreases. The PCM supplies a reference 5 V to the TPS and the output voltage increases directly with the opening of the throttle valve. The TPS output voltage will vary from 0.2 - 0.8 V at closed throttle to 4.3 - 4.8 V at wide-open throttle.
DTC DESCRIPTION
PCM sets DTC P0122 if the PCM detects signal voltage lower than the possible range of a properly operating TPS.
DTC Detecting Condition:
Specification:
Schematic Diagram:
SCHEMATIC DIAGRAM
SIGNAL WAVEFORM & DATA
When checking TPS wave form, it is strongly recommended to examine wave form with MAP sensor wave form.
1. Period (1) is the voltage of MAP in idling and 0.8 - 1.2 V,and there must be a little fluctuation in wave form.
In case there is no fluctuation
Possible cause Deteriorated MAP sensor or some foreign material in TPS sensor.
MONITOR DTC STATUS
This is the inspection procedure to determine whether it is present DTC or memoried one by monitoring the current signal or by using the function of oscilloscope with Hi-scan pro.
1. Connect scantool to Data Link Connector(DLC).
2. Warm up the engine to normal operating temperature.
3. Monitor the "TPS signal" parameter on the scantool.
NOTE: The data shown above is only for reference and there may be a little difference actually
It is normal that the output of TPS changes in accordance with that of MAP sensor.
Service standard
Idle: 0%(250 - 850 mV)
Gradually open: Increases
Open fully: 75 - 85%(4000 - 4800 mV)
4. Is parameter displayed within specifications?
YES: Fault is intermittent caused by poor contact in the sensor's and/or PCM's connector or was repaired and PCM memory was not cleared.
Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination,deterioration, or damage. Repair or replace as necessary and then go to "Verification of Vehicle Repair" procedure.
NO: Go to "W/Harness Inspection" procedure
TERMINAL & CONNECTOR INSPECTION
1. Many malfunctions in the electrical system are caused by poor harness and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination,deterioration, or damage.
3. Has a problem been found?
YES: Repair as necessary and go to "Verification of vehicle Repair" procedure.
NO: Go to "Power Circuit Inspection" procedure.
POWER CIRCUIT INSPECTION
1. Ignition "OFF"
2. Disconnect TPS sensor connector.
3. Ignition "ON" & Engine "OFF"
4. Measure voltage between terminal 3 of sensor harness connector and chassis ground.
Specification : approximately 5 V
5. Is measure voltage within Specification?
YES: Go to "Signal circuit inspection" procedure.
NO:
- Open circuit or short circuit to chassis ground between TPS harness connector and reference voltage.
- Open circuit or short circuit to chassis ground between TPS harness connector and PCM connector.
- Repair as necessary and then go to "Verification of Vehicle Repair" procedure.
NOTE: In case, when the TPS connector is disconnected, the voltage of TPS terminal 2 is 0 V
- Possible cause: Open or short between terminal 32 of PCM and Terminal 2 of TPS
SIGNAL CIRCUIT INSPECTION
1. Check for short to ground in harness
1. Ignition "OFF"
2. Disconnect TPS sensor connector and PCM connector.
3. Ignition "ON" & Engine "OFF"
4. Measure resistance between terminal 1 and 2 of sensor harness connector.
Specification: infinite
5. Is measure resistance within Specification?
YES: Go to "Component Inspection" procedure.
NO:
- Short circuit to ground between TPS harness connector and signal circuit.
- Repair as necessary and then go to "Verification of Vehicle Repair" procedure.
NOTE: In case,when the TPS connector is disconnected,the voltage of TPS terminal 1 is 0 V.
- Possible cause: Open or short between terminal 16 of PCM and terminal 1 of TPS.
COMPONENT INSPECTION
1. Check TPS
1. Measure resistance between terminal 1 and 2 of sensor connector(To sensor side)
2. Measure resistance between terminal 2 and 3 of sensor connector(To sensor side)
Specification: terminal 1 and 2, terminal 2 and 3
close: 0.71 - 1.38 kOhms, 1.6 - 2.4 kOhms
open : 2.2 - 3.4 kOhms
3. Does each resistance indicate continuity circuit?
YES: Go to "Check PCM" as below.
NO:
- Open circuit TPS.
- Repair as necessary and then go to "Verification of Vehicle Repair" procedure.
2. Check PCM
The purpose of checking PCM is to determine whether there is any malfunction of PCM.
1. Ignition "OFF"
2. Connect Scantool and Engine "ON"
3. Select simulation function on scantool.
4. Simulate voltage at terminal 1 of TPS sensor signal connector.
5. Verify TPS voltage to change while raising or lowering simulation voltage with scan tool within 0.5 - 3.5 V
Specification: If the data is changeable as simulation voltage changes, it's OK
6. Is TPS signal value changed according to simulation voltage?
YES: Check TPS for contamination, deterioration, or damage. Clean TPS with suitable cleaner as necessary and let air dry before reinstalling. If problem still exists, Substitute with a known-good TPS and check for proper operation.
If the problem is corrected, replace TPS and then go to "Verification of vehicle Repair" procedure.
NO: Substitute with a known-good PCM and check for proper operation. If the problem is corrected, replace PCM and then go to "Verification of Vehicle Repair" procedure.
VERIFICATION OF VEHICLE REPAIR
After a repair, it is essential to verify that the fault has been corrected.
1. Monitor and record the Freeze Frame Data for the Diagnostic Trouble Code (DTC) which has been diagnosed.
2. Using a Scantool, Clear the DTCs.
3. Operate the vehicle within conditions noted in the freeze frame data or enable conditions.
4. Monitor that all rediness test have been verified as "Complete"
5. Are any DTCs present?
YES: Go to the applicable troubleshooting procedure.
NO: System is performing to specification at this time.