Engine Controls - Multiple Driveability Symptoms

Group
36 - ENGINE
ELECTRICAL

Number
01-36-027

Date
11-2001

Model
Accent 2000-2002 and Elantra 2002-2002

Subject
THROTTLE POSITION SENSOR (TPS) DRIVEABILITY SYMPTOMS

DESCRIPTION:

If a 2001-02 Elantra or 2000-02 Accent is experiencing the following symptoms:

^ Unstable idle

^ Uneven throttle response

^ Slip and shock during the 1-2 and 2-3 shift on Automatic Transaxle (ATM) equipped vehicles

^ Erratic ATM shifts with possible shift flare (engine RPM increase during shifts)

^ Check engine light is ON (may go off but the code will remain stored)

^ TPS related code stored in the ECM and/or TCM

REPAIR INFORMATION:

1) TEST # 1: If a faulty TPS is suspected and the ECM/TCM has no codes stored, conduct the following test for high idle:

^ Have the vehicle idling (with all accessories turned off), transmission in park (ATM) or neutral (MTM), and the hand brake fully applied.

^ Using the Hi-Scan Pro's flight recording menu, observe and record the TPS, Idle Switch Position and engine RPM.

^ Slowly operate the throttle cam to increase the engine speed to about 2500 rpm (use the Hi-Scan Pro to observe the engine speed).

^ Slowly release the throttle cam back to the idle position. Observe the TPS and engine RPM readings on the Hi-Scan Pro.

^ Repeat the above process 10 times.





^ If the engine speed at idle is higher than normal and the TPS reads higher than 0.0 degrees and the Idle Switch indicates "off", replace the TPS.

2) TEST # 2: If a faulty TPS is suspected and the ECM/TCM has no codes stored, conduct the following test for unstable TPS output:

^ Have the vehicle idling (with all accessories turned off), transmission in park (ATM) or neutral (MTM), and the hand brake fully applied.

^ Using the Hi-Scan Pro's flight recording menu, observe and record the TPS and engine RPM.

^ Slowly operate the throttle cam to increase the engine speed to about 2000 RPM (use the Hi-Scan Pro to observe the engine speed).

^ Hold the engine speed steady at 2000 RPM. Observe the TPS and engine RPM readings on the Hi-Scan Pro.

^ Repeat the above process 5 times.





^ If the TPS reading is unstable, replace the TPS. A stable TPS reading is one that changes less than 0.5 degrees at a steady state condition.

^ Repeat the above procedure for 3000 and 4000 RPM to look for an unstable spot in the TPS output.

3) If the BCM has a TPS related code stored (with or without the MIL on), replace the TPS.





PARTS INFORMATION:

WARRANTY INFORMATION:

Normal warranty applies.