Diagnosis A/t: Overview Suzuki Vitara I

Electronic Shift Control System Description

The gear ration change in "D" or "2" range and torque converter clutch operation are controlled by Powertrain (Engine) Control Module.

Scheme 185

Scheme 186

Shift Lock Solenoid Control Operations

When the select lever (1) is in "P" range, the ignition key position is "ON" and depressing the brake pedal cause the electronic current to flow to the solenoid. As the shift lock solenoid rod (3) (or the lock plate (5) is drawn toward the solenoid (4) in this state, is frees the interlock cam (2) or the detent pin (6)), which then allows the select lever (1) to be shifted from "P" range to any other position.

Even when the select lever (1) is in "P" range, if the ignition key position is "LOCK" or "ACC" or the brake pedal is not depressed, the electric current does not flow to the solenoid (4).

In this state, the shift lock solenoid rod (3) (or the lock place (5)) is pushed away from the solenoid (4) by spring force and it obstructs the interlock cam (2) (or the detent pin (6)) movement. Thus the select lever button does not work even when pressed and the select lever (1) shift is prevented.

Scheme 187

Automatic Transmission Diagnosis General Description

This vehicle is equipped with an electronic transmission control system, which control the automatic shift up and shift down timing, TCC operation, etc. suitably to vehicle driving condition.

PCM has an On-Board Diagnosis system which detects a malfunction is this system and abnormality of those part that influence the engine exhaust emission.

When diagnosing a trouble in the transmission including this system, be sure to have full understanding of the outline of On-Board Diagnostic System Description and each item in Precautions in Diagnosing Trouble and execute diagnosis according to A/T System Check to obtain correct result smoothly.

On-Board Diagnostic System Description

For automatic transmission control system, PCM has the following functions.

For the detail, see ECM POWER & GROUND CIRCUITS .

Scheme 188

1. When the ignition switch is turned ON with the engine at a stop, malfunction indicator lamp (MIL) turns ON to check the bulb of the MIL.
2. When PCM detects a malfunction in A/T control system (and/or a malfunction which gives an adverse effect to vehicle emission) while the engine is running, it makes the malfunction indicator lamp in the meter cluster of the instrument panel turn ON and stores the malfunction area (DTC according to SAE J2012) in its memory. (If it detects that continuously 3 driving cycles are normal after detecting a malfunction, however, it makes MIL turn OFF although DTC stored in its memory will remain.)
3. It is possible to communicate through DLC by using not only SUZUKI scan tool but also OBD-II generic scan tool which are in compliance with SAE J1978. (Diagnostic information can be accessed by using a scan tool.)

"O/D OFF" Lamp Operation Check

1. Turn ignition switch to ON position.
2. Check that "O/D OFF" lamp lights for about 2-4 sec. and then goes OFF. If anything faulty is found, advance to «"O/D OFF" Light Does Not Light at ignition Switch ON but Engine Starts Up»(ref-182333-S29462165472005080800000) or «"O/D OFF" Light Comes ON-Steadily»(ref-182333-S01971365312005080800000) .

"POWER" Lamp Operation Check

1. Check that Power/Normal change switch button is at Normal position.
2. Turn ignition switch to ON position.
3. Check that "POWER" lamp lights for about 2-4 sec. and then goes OFF. If anything faulty is found, advance to «"O/D OFF" Light Does Not Light at ignition Switch ON but Engine Starts Up»(ref-182333-S29462165472005080800000) or «"O/D OFF" Light Comes ON-Steadily»(ref-182333-S01971365312005080800000) .

DTC IDENTIFICATION A/T

System Description

PCM turns TCC solenoid off under the following conditions

1. Brake pedal switch: ON
2. "4WD LOW" switch: ON
3. Cruise control module (if equipped): TCC OFF command signal is output.
4. ECT: ECT < 30°C (86°F)

Scheme 189

Scheme 190

PCM does not shift to O/D gear under any following conditions

1. O/D cut switch: ON
2. "4WD LOW" switch: ON
3. Cruise control module (if equipped): O/D OFF command signal is output.
4. ECT: ECT 30°C (86°F)