Mazda RX-8 Manual page 1108

NO.8 LOW MAXIMUM SPEED AND POOR ACCELERATION
8 Low maximum speed and poor acceleration
•
DESCRIPTION
•
•
•
POSSIBLE
CAUSE
NOTE:
•
Vehicle acceleration is poor at start.
Delayed acceleration when accelerator pedal is depressed while driving.
Engine malfunction
Clogged air cleaner, inaccurate ignition timing, ignition leak, reduced
compression, incorrect engine torque signal, etc.
AT malfunction
Transmission fixed in 3GR (operating fail-safe function)
Input/output signal malfunction (VSS, turbine sensor, TFT sensor, pressure
control solenoid, TCC solenoid, shift solenoids A, B, C and F)
Maximum speed is low or acceleration is poor because 3GR is fixed
•
as a fail-safe. In such cases, DTC is stored.
Improper TCM ground
Transmission is mechanically fixed in 3GR if TCM stops operating
•
due to improper TCM ground. In such cases, DTC is stored.
Improper ground of GND return circuit at AT
If there is improper ground of GND return circuit, clutch pressure
•
may decrease, causing clutch slippage.
Improper adjustment TR switch
Incorrect characteristic of accelerator position sensor, accelerator position
signal, TP sensor, or throttle opening angle signal (CAN communication)
TP sensor and throttle opening angle signal (CAN communication) do
•
not change in proportion to throttle opening angle. Due to this, high or
low gear is fixed, resulting in low maximum speed and poor
acceleration. (Refer to improper accelerator position sensor,
accelerator position signal, TP sensor, throttle opening angle signal
(CAN communication) in "No.11 Abnormal shifting".)
Clutch slippage (low clutch and high clutch)
In the event of clutch slippage, a DTC (incorrect gear ratio) is stored.
•
Reduced line pressure
Control valve body malfunction (improper operation, stuck, clogged oil
passage)
Hydraulic circuit clogging (Shift solenoid A, B, C and F, and TCC
•
solenoid)
Control valve spool malfunction
•
No torque generated.
Torque converter malfunction (improper operation)
•
Before following the troubleshooting steps, make sure that the Automatic
Transmission On-Board Diagnostic and Automatic Transmission Basic Inspection
(w) RX-8 Transmission (Manual & Auto)
Page 83