Low RPMs on warm up

GRIT211

MEMBER
2009 HYUNDAI SANTA FE
3.5L
V6
2WD
AUTOMATIC
163,000 MILES

I have replaced just about everything I can think of to fix this issue, the vehicles RPMs will drop to about 450 to 500 after warm up causing the engine to bog down, even more if I use the defroster or heat. Now I have replaced the ignition coils, alternator, camshaft position sensor both, timing position sensor both. Throttle position sensor, spark plugs. I get an engine check light if the bogging engine stayed at the RPMs when warmed up. If the RPMs stay at about 700 to 800 at idle there is no issue. This is all while in park or sitting with the break applied at idle. There seems to be a voltage drop after warm up.

Wednesday, March 17th, 2021 AT 1:50 AM

1 Reply

ASEMASTER6371

MECHANIC
52,796 POSTS

Good morning,

This could be the throttle body itself. There is a motor in the throttle body that positions the throttle plate to the correct angle for engine RPM.

I would start by cleaning it out of all carbon to be sure it is able to move. If it is clear of carbon, I would replace the throttle body and have the PCM software updated.

https://www.2carpros.com/articles/throttle-actuator-service

Roy

Description

The Electronic Throttle Control (ETC) System consists of a throttle body with an integrated control motor and throttle position sensor (TPS). Instead of the traditional throttle cable, an Accelerator Position Sensor (APS) is used to receive driver input. The ECM uses the APS signal to calculate the target throttle angle; the position of the throttle is then adjusted via ECM control of the ETC motor. The TPS signal is used to provide feedback regarding throttle position to the ECM. Using ETC, precise control over throttle position is possible; the need for external cruise control modules/cables is eliminated.

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