Elements of the automatic transmission control lever mechanism
1 - automatic transmission control lever; 2 - housing of the automatic transmission control lever; 3 - cable support; 4 - cable tensioner; 5 - mounting lever with a pin on the gearbox.
To adjust the tension of the cable, select a position «D». Move the cable support until the value is set «A» (equal to 131 mm) between the middle of the fastening pin and the end face of the support.
The electronic control device processes signals from various elements:
- The automatic transmission control lever with multifunction switch is designed to determine the position of the lever. The position of the lever also controls the activation of the reversing lights and the starter lock when in gear.
- The Comfort/Sport switch, together with the automatic transmission control lever, serves to determine the desired shift mode.
- The throttle valve potentiometer is used to determine the position of the throttle valve. This signal is needed to calculate the optimum switching points for the actual motor load.
- A speed sensor is installed in the gearbox to determine the driving speed and also to calculate the optimum shift points.
- The accelerator kick switch is located in the throttle control cable; it gives a signal that the gas pedal is fully depressed. As a result, shifting to a higher gear will occur a little later or, if necessary, shifting to 1 or 2 gears lower.
- The brake light switch is used to unlock the electromagnetic latch of the automatic transmission control lever. Only with the brake pedal depressed and the gas pedal released can the automatic transmission control lever be moved from the position «P» or «N» into any gear position.
- The ATF temperature sensor is used to detect the temperature of the drive fluid. Significant difference between engine speed and transmission speed can cause significant heating of the ATF. By constantly measuring the temperature of the ATF, the microprocessor in the control unit calculates the required fluid pressure and adapts it to the actual situation. This reduces slippage in the torque converter and helps lower the temperature of the ATF.
Switching process control
If you move the automatic transmission control lever to the «D», ATF under pressure enters the spool (to the shift valve) in a golden box. These spools hydraulically control the clutches and brake bands. In this case, the pressure is regulated by means of a control device with solenoid valves and thus the moment of switching to a lower or higher gear is determined, and also ensures «softness» switching process.
Self control
The electronic control device can recognize and store faults that occur. To do this, the control program monitors the input and output signals of all sensors and elements of the box, as well as their electrical circuits. Faults that have occurred are stored in long-term memory. In the workshop, the memory device is examined by a special diagnostic tool for any records of malfunctions. If you suspect that there is a malfunction in the control of the automatic transmission, then you can obtain information about this from the memory of the control unit only at a Renault workshop.
Control lamp of an automatic transmission
For notification of malfunctions, the instrument panel has a control and warning lamp.
- Normal indication: to the position of the automatic transmission control lever «P» or «N» The lamp lights up when the ignition is on and the engine is started.
- After you release the ignition key and the engine starts, the lamp will go out after 3 seconds.
- Malfunction indication: when the engine is idling or when driving, the lamp is constantly on.
- The lamp flashes for a short time.
- The lamp flashes while driving.
- When the vehicle is stationary or while driving, the lamp lights up for approximately 1 second.
This is possible at temperatures below -20°C or above 140°C. In this case, you need to slow down until the normal temperature of the ATF is reached.
Emergency program
If the control device detects a malfunction that has a significant negative effect on the automatic transmission, or if the control device itself is faulty, an emergency driving program comes into effect. The automatic transmission then only shifts up to 3rd gear. In this way, you, as the driver, receive a signal to recognize a defect in the automatic transmission. You can also turn on transmission «R».
Checking the automatic transmission
On their own, a motorist can fix almost nothing in an automatic transmission. Checks help, however, to detect a malfunction, which is very useful when buying a used car.
1. In case of malfunctions, first check the ATF level in the gearbox.
2. If the ATF smells burnt on the dipstick, then complex damage to the automatic transmission is possible. In this case, the clutches or brake bands may be faulty.
3. At a test drive check up smoothness of a gear change.
4. How the shift occurs indicates the status of the automatic transmission.
5. Correct cable adjustment «gas» and shifting is an important prerequisite for the perfect operation of an automatic transmission.
Evaluation of the gear shift process
1. During a test drive, pay attention to the gear change process:
2. Upshifting:
3. With a partially depressed gas pedal, gear shifting is barely noticeable;
4. When you open the throttle fully or when you press the accelerator pedal hard, you will feel some distinct transitions, although upshifting should always be perceived as soft. A momentary increase in speed when shifting gears indicates a malfunction, the cause of which must be determined.
5. Transition from higher to lower gears: without «gas» (when coasting) barely perceptible at very low speeds. It is normal to jerk at partial or full load. Downshifting «without gas» manually using the automatic transmission control lever lasts up to 2 seconds. If when downshifting with the control lever «gas», then the gear shift occurs without delay.
Automatic transmission shift points
1 to 2 | From 2 to 3 | 3 to 4 | 4 to 3 | 3 to 2 | From 2 to 1 | |||||||
Gearbox MB3 Partially depressed pedal «gas» Full «gas» Hard pressed pedal «gas» | 23 72 72 | 40 118 118 | — — — | — — — | 27 102 102 | 15 63 63 | ||||||
Shift knob in position | C | S | C | S | C | S | C | S | C | S | C | S |
Gearbox AD4 Partially depressed pedal «gas» Full throttle Hard pressed pedal «gas» | 17 36 42 | 20 42 44 | 35 70 | 40 80 | 60 117 | 70 128 | 47 103 | 50 112 | 30 | 10 | ||
26 | 30 | |||||||||||
80 | 131 | 130 | 52 78 | 68 81 | 40 |
Note. Recommendation: if the Renault 19 engine with automatic transmission does not start, then towing will not help you. The torque converter does not provide connection to the engine if the engine is not running. You can only help «smoking» using an additional cable from another vehicle. If you need to tow the car, then this is done in the position «N» the automatic transmission control lever for a distance of up to 50 km at a maximum speed of 50 km/h! Adjustment work and, above all, repairs should only be carried out in a workshop.