Canada - Engine Controls - TPS Driveability Issues
GROUPENGINE ELECTRICAL
NO.
00-36-003
DATE
JULY 21/00
MODEL
96-99 ACCENT
96-00 ELANTRA
97-00 TIBURON
SUBJECT
THROTTLE POSITION SENSOR (TPS)
DRIVEABILITY SYMPTOMS
The Throttle Position Sensor (TPS) used on Hyundai vehicles is a potentiometer type (variable) resistor. It senses how far the throttle plate is open which is based on the position of the accelerator pedal which controls the throttle cable.
As system voltage (5 volts) is applied through the TPS's resistor to ground a moveable contact on the resistor provides a variable signal to the ECM as the throttle body's throttle plate opens and closes. Since the natural phenomenon of electricity is to follow the "path of least resistance" the electrical signal flows along the moveable contact (since there is less resistance) which depending on the contacts position on the resistor is interpreted by the ECM to represent how much the throttle plate is open.
If the ECM does not receive the signal from the TPS, or receives an incorrect signal based on engine load, at any point between the fully closed to the fully open position, driveability will be affected. Some of the symptoms may include:
^ Unstable idle
^ Poor throttle response
^ Slight hesitation/stumble
^ Shift shocks or slipping between gears (ATM only)
^ TPS related Diagnostic Trouble Codes (DTCs) stored in the ECM and/or the TCM
^ Malfunction Indicator Lamp (MIL) ON (may go OFF but DTC will remain)
If you suspect that a vehicle's TPS is not operating properly check if ALL three of the following are also present:
^ there are no DTCs stored in the ECM or the TCM
^ the MIL is OFF
^ and, the TPS has the words "DAE SUNG" moulded on its side
If all three are present we recommend that you perform the following procedure:
1. Start the vehicle and let it idle with all accessories OFF.
2. Push on the side of the TPS connector (towards the vehicles interior)
Important:
The pressure should be enough to deflect the TPS housing but not so much to cause damage or break anything.
^ If the TPS is not operating properly the engine should surge in response to the push.
^ If the Hi-Scan Pro is used to record the TPS output this procedure should show that the TPS output voltage increases when pushed.
a) If the engine surges and/or the TPS output voltage increases, then the TPS should be replaced.
b) If the engine does not surge and/or the TPS output voltage does not show an increase, then the TPS is operating normally and does not require replacement.
3. If the ECM has a TPS related DTC stored in memory after this test (with or without the MIL ON) then the TPS should be replaced.
Parts Information
Warranty Information:
Normal warranty policies and procedures apply