P0638
DTC P0638 THROTTLE ACTUATOR CONTROL RANGE/PERFORMANCEComponent Location:
GENERAL DESCRIPTION
The Electronic Throttle Control (ETC) system is made of the components throttle body, Throttle Position Sensor (TPS)1 & 2 and Accelerator Position Sensor (APS) 1 & 2. The throttle body contains the actuator, the throttle plate and the throttle position sensor (potentiometer), which are integrated in one housing. The actuator consists of a DC motor with a two-stage gear. The opening angle of the throttle valve is detected by the throttle position sensor which is mounted on the throttle body. And it provides feedback to the ECM to control the throttle motor in order to control the throttle valve opening angle properly in response to the driving condition.
DTC DESCRIPTION
ECM sets DTC P0638 if the ECM detects TPS adaptation value exceeds threshold value
DTC Detecting Condition:
Specification:
Schematic Diagram:
Signal Waveform And Data Part 1:
Signal Waveform And Data Part 2:
MONITOR DTC STATUS
1. Connect scan tool and select "Diagnostic Trouble Codes (DTCs)" mode.
2. Press F4 (DTAL) to select DTC information from the DTCs menu.
3. Confirm that "DTC Readiness Flag" indicates "Complete". If not, drive the vehicle within conditions noted in the freeze frame data or enable conditions.
4. Read "DTC Status" parameter.
5. Is parameter displayed "History (Not Present) fault"?
NOTE:
- History (Not Present) fault : DTC occurred but has been cleared
- Present fault : DTC is occurring at present time
YES - Fault is intermittent caused by poor contact in the sensor's and/or the ECM's connector, which was repaired but ECM memory was not cleared. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure
NO - Go to next step as below
COMPONENT INSPECTION
NOTE: It is necessary to perform the TPS adaptation procedure with Scan tool when the throttle body assembly or ECM is replaced.
- TPS adaptation procedure
1. Erase previous TPS adaptation value using Scan tool.
2. Ignition "OFF" and then "ON" without cranking. Wait for 10 seconds under enable conditions
- Enable conditions : Battery 10 V & Intake Air Temp. 5.3 °C(41.5 °F) & 5.3 °C(41.5 °F) Engine Coolant Temp. (99.8 °C (211.6 °F)
3. After TPS adaptation, the system normality should be confirmed by reading out "FMY" on the Scan Tool.
TPS INSPECTION
1. Start engine and install scan tool.
2. Monitor the "TPS VOLTAGE 1" and "TPS VOLTAGE 2" parameters on the Scantool data list.
Specification : Refer to "Signal Waveform & Data" in the "General Information" procedure
- Output of TPS 1 increases smoothly in proportion with the throttle valve opening angle.
- Output of TPS 2 decreases smoothly in inverse proportion with the throttle valve opening angle.
3. Are the TPS VOLTAGE 1 & 2 within the specification?
YES - Go to next step as below
NO - Check TPS 1 & 2, referring troubleshooting guide for DTC PO1 21/P0221. Repair or replace as necessary and go "Verification of Vehicle Repair" procedure
ETC MOTOR INSPECTION
1. Visually/physically inspect the restriction or any foreign objects in throttle body.
2. Clean or replace as necessary and go to "Verification of Vehicle Repair" procedure. If OK, go to next step as below
3. Ignition "OFF".
4. Disconnect the ETC motor harness connector.
5. Measure resistance between terminals 3 and 6 of the ETC motor connector (Component side).
Specification : 1.2 - 1.8 Ohms at 20 °C(68 °F)
6. Is resistance within the specification?
YES - Go to next step as below
NO - Check throttle body for contamination, deterioration, or damage. Substitute with a known-good throttle body and check for proper operation. If the problem is corrected, replace throttle body and then go to "Verification of Vehicle Repair" procedure.
CONTROL CIRCUIT INSPECTION
Check for open or short circuit in ETC motor harness
1. Reconnect the ETC motor connector.
2. Disconnect ECM connector.
3. Measure resistance between terminals 71 and 72 of the ECM harness connector.
Specification : 1.2 - 1.8 Ohms at 20 °C(68 °F)
4. Is resistance within the specification?
YES - Go to next step as below
NO - Check for open or short in control harness. Repair as necessary and go to "Verification of Vehicle Repair" procedure
TERMINAL AND CONNECTOR INSPECTION
1. Many malfunctions in the electrical system are caused by poor harness(es) 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 - Check for poor connection between ECM and component: backed out terminal, improper mating, broken locks or poor terminal to wire connection. Repair as necessary and 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. Connect scan tool and select "Diagnostic Trouble Codes (DTCs)" mode.
2. Press F4 (DTAL) and confirm that "DTC Readiness Flag" indicates "Complete". If not, drive the vehicle within conditions noted in the freeze frame data or enable conditions.
3. Read "DTC Status" parameter.
4. Is parameter displayed "History (Not Present) fault"?
YES - System performing to specification at this time. Clear the DTC
NO - Go to the applicable troubleshooting procedure.