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2008 Hyundai Optra 1.6L Engine Stalls at Idle with P0562 History - Throttle Position Sensor Issue?

Model: 2008 Optra Fault Code: P0562 Posted: 2017-06-26 12:46

Hi everyone, I recently experienced a recurring engine stall issue on my 2008 Hyundai Optra 1.6L automatic transmission model. The problem initially manifested as an error code P0562, which I traced back to a loose battery terminal. After tightening the connection and restoring proper voltage, the P0562 code cleared. However, today I noticed multiple instances of engine stalling at idle. I used my Autel MD802 scanner to check for active or pending codes, but no errors were recorded. I performed a manual idle relearn procedure, which reduced throttle fluctuation significantly—but the issue still persists. My main concern is whether the prior P0562 event—especially with low battery voltage—could have damaged or disrupted the throttle position sensor (TPS) calibration at idle. Does this old fault code affect idle stability and require a reset via an advanced diagnostic tool? Additionally, I’ve observed inconsistent TPS readings: at idle, the voltage reads 4.1V with a throttle position of ~6.5%, while at wide open throttle (WOT), it drops to 0.5V with 70% throttle. According to manufacturer specifications (e.g., AA1Car.com), the voltage should increase from low to high as throttle opens, not decrease. I’ve already replaced spark plugs and wires, cleaned the throttle body, inspected all vacuum lines, and changed the fuel filter—none of these resolved the issue. Fuel trims remain stable at 0.0 during driving and 0.8 at idle. The engine transitions to closed-loop operation after shifting into drive (D) within 2–3 minutes, and O2 sensor readings fluctuate between 200 and 800 mV in a continuous wave. Could the TPS be faulty? Or is there another underlying issue affecting idle stability? Any insights or recommendations would be greatly appreciated.

Related fault codes
P0562
Comments (9)
Anonymous 2017-06-26 12:49

If battery voltage is stable and P0562 has cleared, it's unlikely that the previous fault directly impacted throttle control. The engine should relearn idle behavior normally after a power cycle or relearn procedure.

Anonymous 2017-06-26 13:22

With consistent battery voltage (14V at 1400 RPM) and no active P0562, the issue is likely not related to the past low-voltage event. Focus should shift to mechanical or sensor-based diagnostics.

Anonymous 2017-06-26 14:13

I’ve confirmed battery and alternator voltage are stable at 14V under load. P0562 has fully cleared. I’m now concerned whether the prior low-voltage incident could have caused a misalignment in the throttle body idle calibration or TPS sensitivity. Could this be affecting idle stability?

Anonymous 2017-06-26 16:43

Start with basic checks: clean the throttle body and intake air control (IAC) valve, then use a scan tool to monitor real-time engine parameters—fuel trims, IAC position, throttle response, and idle speed. These will help isolate whether the issue lies in sensor readings or mechanical function.

Anonymous 2017-06-30 07:44

Thank you for the helpful input, CJ1!

Anonymous 2017-07-05 17:03

Hi all—I own a 2008 Optra 1.6L L4 (LXT model). I'm experiencing rough idle, severe hesitation when cold, stalling during A/C switch-off at idle, and high fuel consumption. RPM fluctuates significantly. Fuel trims are stable at 0.0 while driving and 0.8 at idle. TPS readings show 4.1V at closed throttle (should be low) and 0.5V at WOT (should be high). I suspect the TPS is damaged, especially given that manufacturer specs state voltage should rise with throttle opening. Reference: https://www.aa1car.com/library/tps_sensors.htm. The manual indicates ignition ON, closed throttle = 0.2–0.9V increasing to over 4.5V at WOT. I have no stored or pending codes. Any advice? Help is urgently needed.

Anonymous 2017-07-05 23:19

If fuel trims don’t shift during driving, verify that the engine is properly transitioning into closed-loop operation. Check when the engine switches from open to closed loop and confirm O2 sensor behavior—should show a stable oscillation between 200–800 mV.

Anonymous 2017-07-06 02:50

The TPS percentage value appears correct, so voltage readings may be accurate for the current system operation. However, it's possible that the scan tool is reading a different sensor or there’s an internal calibration issue. A factory service manual would provide definitive verification of expected values. Also, check if your scan tool reports misfire counts—this could indicate underlying combustion issues.

Anonymous 2017-07-06 11:50

Since the TPS percentage is within specification, voltage readings may still be valid for system operation. Confirm that there’s a pedal position sensor in place and functioning correctly. The scan tool might be reading this sensor instead of the TPS. A factory service manual is essential to validate expected values. Also, check misfire counts on your scan tool—this could reveal hidden engine issues.