For 1990-2009 cars

The Vehicle Speed Sensor (VSS) (Transaxle) consists of a magnetic core with a magnet and coil.

The VSS (Transaxle) is mounted in the transaxle case with 0.6 mm (0.024 in) air gap between the core end and the countershaft gear tooth.

When the countershaft rotates, magnetic flux is cut by the countershaft gear teeth.

This action sends a pulse which is generated in the VSS coil according to the speed.

The pulse signal is then transmitted to the PCM as a speed signal.

### Throttle Position (TP) Sensor

The Throttle Position (TP) sensor is located on the side of the throttle valve and supplies a throttle position input to the Powertrain Control Module (PCM). This input informs the PCM of the rate at which the throttle plate is opening. The PCM uses this input to determine shift points and when necessary, to downshift the transaxle.

### Engine Coolant Temperature (ECT) Sensor

The Engine Coolant Temperature (ECT) sensor is located on the thermostat housing. The ECT sensor uses a thermistor to control the signal voltage to the Powertrain Control Module (PCM). The PCM delays the lock-up of the Torque Converter Clutch (TCC) until the engine coolant has reached an operating temperature of 55°C (131°F).

### Camshaft Position (CMP) Sensor

The engine speed input is supplied to the Powertrain Control Module (PCM) from the Camshaft Position (CMP) sensor located within the distributor housing. The PCM uses this input to determine when the Torque Converter Clutch (TCC) should engage for the best fuel economy. The PCM also compares this input to the vehicle speed input (from the Vehicle Speed Sensor [VSS]) to calculate transaxle efficiency.

### Park/Neutral Position (PNP) Switch

The Park/Neutral Position (PNP) switch is located next to the solenoid wire harness and is controlled by the shift select cable. The PNP switch sends a signal to the Powertrain Control Module (PCM) when the manual selector is in the P,R,N,2 and L. The PCM uses these signals to determine which gear has been selected and to determine shift points and Torque Converter Clutch (TCC) engagement.

### Overdrive Switch

The Overdrive switch is located on the manual selector and allows the driver to select the overdrive gear. When the overdrive switch is pressed, the Powertrain Control Module (PCM) receives a signal indicating the position of the overdrive switch. With this signal present, the PCM adds a 4th gear to the transaxle shift schedule above 3rd gear. When the overdrive switch is released, the PCM returns the transaxle to its normal 3-speed shift schedule. The overdrive gear can only be selected with the manual selector in Drive (D) position. The PCM delays the engagement of the 4th gear until the engine coolant has reached an operating temperature of 55°C (131°F).

### Stoplamp Switch

The stoplamp switch is located on the upper part of the brake pedal. When the brake pedal is pressed (stoplamp switch closes) during Torque Converter Clutch (TCC) operation, the Powertrain Control Module (PCM) removes voltage from the TCC solenoid. The solenoid de-energizes and disengages the lock-up clutch. The signal is used to prevent the engine from stalling if the front wheels were to lock-up.

### O/D OFF Indicator

The O/D OFF indicator is activated whenever the Overdrive switch is not pressed. When the O/D OFF indicator is activated, it informs the driver that the transaxle is following a normal 3-speed shift schedule.

### Shift Solenoids

The shift solenoids 1 and 2 are located on the valve body assembly and are controlled by the Powertrain Control Module (PCM). The PCM controls the solenoids independently of each other based on the position of the Throttle Position (TP) sensor. The shift solenoids control delivery of the fluid line pressure to the mechanical shift valve in the transaxle valve body assembly. If both solenoids fail, the transaxle will use line pressure to shift the transaxle and provide minimum driveability until the malfunction in the electronic control system can be repaired. The PCM delays the engagement of the 4th gear (Overdrive) until the engine coolant has reached an operating temperature of 55°C (131°F).

### Torque Converter Clutch (TCC) Solenoid

The Torque Converter Clutch (TCC) solenoid is located on the valve body assembly and is used for applying the TCC. The TCC lockup will occur in 3rd and 4th gears. The Powertrain Control Module (PCM) delays the engagement of the TCC until the engine coolant has reached an operating temperature of 55°C (131°F).

### Upshifts and Torque Converter Clutch (TCC) Apply

With the manual selector in Drive (D) position and the Overdrive switch pressed, accelerate the vehicle steadily using increased throttle pressure. Note the vehicle speeds and shift points for:

• | 2nd gear

• | 3rd gear

• | Overdrive

Evaluation
Note the vehicle speeds and the shift points at which the Torque Converter Clutch (TCC) engages. The TCC apply should occur in 3rd and O/D.

Important: The TCC will not apply and 4th gear (Overdrive) upshift is delayed until the engine coolant temperature has reached at least 55°C (131°F).

### Part Throttle Downshift

At vehicle speeds of 64 to 88 km/h (40 to 55 mph) with the manual selector in the Drive (D) position and the Overdrive switch pressed, quickly press the accelerator pedal to approximately half the throttle and verify:

• | TCC release.

• | Transaxle immediately downshifts to 3rd gear.

### Full Throttle Downshift

At vehicle speeds of 77 to 88 km/h (48 to 55 mph) with the manual selector in Drive (D) and the Overdrive switch pressed, quickly press the accelerator pedal to a Wide Open Throttle (WOT) position and verify:

• | Torque Converter Clutch (TCC) release.

• | Transaxle immediately downshifts to 2nd gear.

### Manual Downshift

At vehicle speeds of 64 to 88 km/h (40 to 55 mph) with the manual selector in the Drive (D) position and the Overdrive switch pressed, release the accelerator pedal, then the Overdrive switch and verify:

• | Torque Converter Clutch (TCC) release.

• | The transaxle downshifts immediately to 3rd gear.

• | Engine slows vehicle down.

| With the manual selector in Drive (D) position, operate the vehicle at 48 km/h (30 mph). Release the accelerator pedal and move the manual selector to the Second (2) position and verify:

• | TCC release.

• | Transaxle downshifts immediately to 2nd gear.

• | Engine slows vehicle down.

• | With the manual selector in the Drive (D) position, operate the vehicle at 24 km/h (15 mph). Release the accelerator pedal and move the manual selector to the Low (L) position and verify:

• | TCC release.

• | Transaxle downshifts immediately to 1st gear.

• | Engine slows vehicle down.

### Coast Down Downshift

With the manual selector in the Drive (D) position and the Overdrive switch pressed, accelerate the vehicle until the transaxle has obtained 4th gear (O/D) and the Torque Converter Clutch (TCC) has applied. Release the accelerator pedal, lightly apply the brake pedal and observe:

• | TCC release.

• | The vehicle speeds at which the transaxle downshifts.

### Manual Gear Range Selection

With the vehicle stopped, place the manual selector in Drive (D) position. Slowly accelerate the vehicle and verify that:

• | Transaxle upshifts from 1st to 2nd gear.

• | Transaxle upshifts from 2nd to 3rd gear.

| With the vehicle stopped, place the manual selector in Second (2) position. Slowly accelerate the vehicle and verify that the transaxle upshifts from 1st to 2nd gear.

| Accelerate to 40 km/h (25 mph) and verify:

• | Transaxle does not upshift from 2nd to 3rd gear.

• | Torque Converter Clutch (TCC) does not engage.

• | With the vehicle stopped, place the manual selector in Low (L) position. Slowly accelerate vehicle and verify:

• | Transaxle does not upshift from 1st to 2nd gear.

• | TCC does not engage.

• | With the vehicle stopped, place the manual selector in Reverse (R) position. Slowly accelerate the vehicle and verify that the vehicle moves in a rearward direction.