MR2 With Sequential Manual Transaxle

NOTE: On MR2 models, 2 types of manual transaxles are used. Standard type manual transaxle in which the driver operates the clutch and shifts the transaxle, and sequential manual transaxle, which is electronically controlled. Clutch is operated and transaxle is shifted hydraulically by moving shift lever forward or backward. Sequential manual transaxle may be identified by shift lever pattern which consists of "R", "N", "S" and "+" in place of the conventional type shift lever pattern and there is no clutch pedal.

On all models, Electronic Throttle Control System (ETCS) consists of throttle body, accelerator pedal position sensor, Throttle Position (TP) sensor, throttle control motor, magnetic clutch and Engine Control Module (ECM). ETCS uses ECM to calculate throttle valve opening in the throttle body in relation to driving conditions. ETCS controls idle speed and cruise control system operation. Accelerator pedal position sensor is mounted on throttle body and is integrated with throttle lever which attaches to the throttle cable. See Fig 1. Accelerator pedal position sensor consists of 2 sensors which deliver input signals to the ECM. TP sensor delivers input signals to ECM to indicate throttle valve opening.

ECM uses these input signals to operate throttle control motor to obtain proper operating speeds in relation to accelerator pedal position and engine speed, obtain proper idle speed, and provide cruise control operation. Throttle control motor is mounted on side of throttle body and operates throttle valve on throttle body by use of a magnetic clutch.

In the event of an ETCS malfunction, Malfunction Indicator Light (MIL) will be illuminated and Diagnostic Trouble Code (DTC) will be stored in ECM. MIL is displayed as an engine icon on instrument cluster on instrument panel. See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieval of DTCs. If malfunction exists, magnetic clutch will be disengaged, allowing spring pressure to close the throttle valve. When magnetic clutch is disengaged, throttle control motor will not operate the throttle valve. If ETCS is shut off, accelerator pedal may be used to operate throttle valve for vehicle operation.

Fig 1: Locating Electronic Throttle Control System Components On Throttle Body (MR2 With Sequential Manual Transaxle)