P2127
P2127Component 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 APS is mounted in the accelerator pedal to detect the opening angle of the accelerator pedal. It has 2 sensors to detect the accelerator position and a malfunction of the accelerator position sensor. The PCM judges the current opening angle of the accelerator pedal from APS1&2, and the PCM controls the throttle motor based on these signals.
DTC Description
Checking output signals from APS 2 under detecting condition, if output signals below the threshold. PCM sets P2127. MIL (Malfunction Indication Lamp) turns on when the malfunction lasts till 1 driving cycle.
DTC Detecting Condition:
Specification:
Schematic Diagram:
Signal Waveform:
Monitor Scantool Data
1. Connect scantool to DLC. (Data Link Connector)
2. Warm up the engine to normal operating temperature.
3. Monitor "APS1 & APS2" parameters on the scantool.
4. Are those "APS1 & APS2" parameters displayed correctly?
YES - Fault is intermittent caused by poor contact in 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 replaces necessary and go to "Verification of Vehicle Repair" procedure
NO - Go to "Terminal and Connector Inspection" procedure.
Terminal and 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 Supply Circuit Inspection
1. IG "OFF".
2. Disconnect APS connector.
3. IG "ON" & ENG "OFF".
4. Measure voltage between terminal 3 of APS harness connector and chassis ground.
Specification: Approx. 5 V
5. Is the measured voltage within specification?
YES - Go to "Signal Circuit Inspection" procedure.
NO - Repair or replace as necessary and then, go to Verification of Vehicle Repair" procedure.
Signal Circuit Inspection
1. Check short to ground in harness
1. IG "OFF".
2. Disconnect APS and PCM connector.
3. Measure resistance between terminal 1 of APS harness connector and chassis ground.
4. Measure resistance between terminal 1 and 5 of APS harness connector.
5. Measure resistance between terminal 1 and 4 of APS harness connector.
Specification: Infinite
6. Is the measured resistance within specification?
YES - Go to "Check open in harness" as follows.
NO - Repair or replace as necessary and then, go to "Verification of Vehicle Repair" procedure.
2. Check open in harness
1. IG "OFF".
2. Disconnect APS and PCM connector.
3. Measure resistance between terminal 1 of APS harness connector and terminal 49 of PCM harness connector.
Specification: Approx. below 1 ohm
4. Is the measured resistance within specification?
YES - Go to "Component Inspection" procedure.
NO - Repair or replace as necessary and then, go to "Verification of Vehicle Repair" procedure.
Component Inspection
1. Check APS
1. Ignition "ON" & ENG "OFF".
2. Measure waveform of APS by pressing and depressing accelerator pedal with scantool.
Specification:
3. Is the measured signal waveform O.K?
YES - 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.
CAUTION: There is a memory reset function on scantool that can erase optional parts automatically detected and memorized by PCM. Before or after testing PCM on the vehicle, use this function to reuse the PCM on the others.
NO - Substitute with a known-good APS and check for proper operation. If the problem is corrected, replace APS 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 readiness 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.