A/T - Unwanted Downshifts

SOURCE: Kia Technician Times

TITLE: Unwanted Downshifts in A/T

APPLIES TO: Sportage

SERVICE TIP:











CONDITION

Vehicle will experience shifting anomalies.

CAUSE

If the PRNDL indicator light circuit board in the instrument panel (see photo 1) is defective, it may backfeed an inappropriate "in-gear" signal to the TCM, thereby initiating or suppressing transmission shift signals at unplanned times.

CORRECTIVE ACTION

1. For no upshift to 4th gear only: Make sure the customer is not misinformed about A/T cold operation. Clarify as required.
2. Verify that the condition is not caused by an erratic TPS signal input. Unless you are sure that the following has already been performed correctly, upgrade the C123/C124 and TPS connectors, splice S116, etc. Next, have an assistant check the TPS input to the ECM during a test drive by displaying the signal as a graph on the scan tool. If the signal is unstable or is interrupted, repair circuit or replace TPS as necessary.
3. Have an assistant closely monitor the PRNDL gear indicator lights in the instrument panel during a test drive. If the indicator light operation is inconsistent (i.e., unusually dim, one of the lights comes on when it is not supposed to, two or more are lit at the same time), disconnect C253 and test the vehicle again without the indicator lights connected. If unwanted shift condition is gone, replace the PRNDL circuit board (see photo 2).