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NO.16 ENGINE FLARES UP OR SLIPS WHEN UPSHIFTING OR DOWNSHIFTING

BHE050301026W21

16 | Engine flares up or slips when upshifting or downshifting
DESCRIPTION | • When accelerator pedal is depressed for driveway, engine speed increases normally but vehicle speed increases slowly. • When accelerator pedal is depressed while driving, engine speed increases but vehicle speed does not.
POSSIBLE CAUSE | • Clutch slippage (low clutch, high clutch). – In the event of clutch slippage, a DTC (incorrect gear ratio) is output. • Reduced line pressure • Input/output signal malfunction (VSS, turbine sensor, throttle opening angle (CAN communication), TFT sensor, pressure control solenoid, shift solenoids A, B, C and F, oil pressure switches B, C and F). • Control valve body malfunction (improper operation, stuck, clogged oil passage). – Hydraulic circuit clogging (Pressure control solenoid, shift solenoids B, C and F). – Control valve spool malfunction • Improper TCM ground • Improper ground of GND return line at AT – If there is improper ground of GND return line, clutch pressure may decrease, causing clutch slippage. Note • Before following the troubleshooting steps, make sure that the Automatic Transmission On-Board Diagnostic and Automatic Transmission Basic Inspection are conducted. (See BASIC INSPECTION.)

Diagnostic procedure

STEP | INSPECTION | ACTION
--- | --- | ---
1 | Is the shift point normal? | Yes | Go to the next step.
No | Go to No.11 "ABNORMAL SHIFTING".
2 | Inspect the following values. (See PCM INSPECTION.) (See TCM INSPECTION.) PCM PIDs (using WDS or equivalent): • APP1 • APP2 • TP_REL • VSS TCM terminal voltage: • 2G (turbine sensor) • 2K (VSS) Are the values normal? | Yes | Go to the next step.
No | Repair or replace any malfunctioning parts.
3 | Disconnect the TCM connector. Is the resistance between terminal 2U at the TCM connector and terminal J at the solenoid valve wiring harness-side connector 5.0 ohms or less? | Yes | Go to the next step.
No | Repair open circuit.
4 | Disconnect the TCM connector. Is the resistance between ground terminal 2M or 2Q at the TCM connector and body ground 5.0 ohms or less? | Yes | Go to the next step.
No | Repair the wiring harness. Reconnect the TCM.
5 | Inspect the TFT sensor. (See TRANSMISSION FLUID TEMPERATURE (TFT) SENSOR INSPECTION.) Is the TFT sensor normal? | Yes | Go to the next step.
No | Replace the TFT sensor.
6 | Stop the engine. Disconnect the solenoid valve connector. Measure the resistance between the following solenoid valve connector terminals. (See SOLENOID VALVE INSPECTION.) • Terminals E-J (shift solenoid A) • Terminals F-J (shift solenoid B) • Terminals H-J (shift solenoid C) • Terminals I-J (shift solenoid F) • Terminals K-J (pressure control solenoid) Are the resistances normal? | Yes | Overhaul the control valve body and repair or replace any malfunctioning parts. (See AT Workshop Manual.) If the problem remains, overhaul the transmission and repair or replace any malfunctioning parts. (See AT Workshop Manual.)
No | Repair or replace malfunctioning parts.
7 | Verify the test results. • If normal, return to the diagnostic index to service any additional symptoms. • If the malfunction remains, inspect the related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. – If the vehicle is repaired, troubleshooting completed. – If the vehicle is not repaired or additional diagnostic information is not available, replace the TCM. (See TCM REMOVAL/INSTALLATION.)