Cruise control not working
Content
In most cases, if the cruise does not work, the brake or clutch pedal sensor is faulty. Often it fails due to damaged wiring and contacts, less often due to problems with electronic components and buttons, and very rarely due to incompatibility of parts installed during the repair process. Usually a problem with cruise control can be solved by yourself. Find out why the car cruise does not turn on, where to look for a breakdown and how to fix it yourself - this article will help.
Reasons why cruise control does not work in a car
There are five basic reasons why cruise control does not work:
- blown fuse;
- damage to electrical contacts and wiring;
- incorrect operation of the failure of sensors, limit switches and actuators involved in cruise control;
- breakdown of electronic cruise control units;
- part incompatibility.
You need to check the cruise control for performance at speed. In most cars, the activation of the system is blocked when the speed does not exceed 40 km / h.
Most often, a simple (passive) cruise does not work due to problems with contacts and limit switches. The ECU will not allow you to turn on the cruise control system, even if it does not receive a signal from one of the sensors due to a broken wiring, oxidation of the terminals, or a jammed “frog”.
The main reasons why the cruise control on the car does not work
| cruise control failure | Why is this happening | How to fix |
|---|---|---|
| Broken or broken buttons | Mechanical damage or oxidation due to moisture ingress leads to loss of electrical contact. | Check the buttons using diagnostics or a standard testing system. The way it is turned on depends on the model, for example, on a Ford, you need to turn on the ignition with the heated rear window button pressed, and then press the keys. If the button is working, a signal will sound. If a break is detected, it is necessary to replace the wire, if the buttons do not work, repair or replace the module assembly. |
| The natural wear of the contact group ("snail", "loop") causes a lack of signal. | Check the contact group, replace if its tracks or cable are worn. | |
| Damaged clutch pedal switch | Spring damage or limit switch jamming due to dirt and natural wear. If the cruise control switches are soured, the system will not activate. | Check the wiring of the limit switch and the sensor itself. Adjust or replace limit switch. |
| Misadjustment of the electronic accelerator pedal | Pedal settings are lost due to wear of the potentiometer track, as a result of which the ECU receives incorrect data on the position of the throttle and cannot correctly control it in cruise mode. | Check the gas pedal potentiometer, its free play, adjust the accelerator stroke. If the pedal outputs incorrect voltages (e.g. too low or too high), replace the pedal sensor or pedal assembly. the pedal may also need to be initialized on the system. |
| Any breakdown of ABS + ESP (powered by ABS) | Wheel sensors and their wires are prone to failure due to dirt, water, and temperature changes. The ABS cannot transmit wheel speed data to the computer due to a broken or broken sensor. | Check the ABS sensors on the wheels and their wires. Repair electrical circuits or replace broken sensors. |
| breakdown in the brake system circuit (brake lights, brake and handbrake pedal position sensors) | Burnt out lamps or broken wires do not allow you to turn on the cruise control for safety reasons. | Replace burned-out lamps, ring the wiring and eliminate breaks in it. |
| Jammed or shorted the position sensor of the brake pedal or handbrake. | Check sensors and their wiring. Adjust or replace the faulty sensor, limit switch, restore the wiring. | |
| Unsuitable lamps | If the car is equipped with a CAN bus and is designed for incandescent lamps in lanterns, then when using LED analogues, problems with the cruise are possible. Due to the lower resistance and consumption of LED lamps, the lamp control unit “thinks” that they are faulty, and the cruise control is turned off. | Install incandescent lamps or LED lamps designed for cars with a CAN bus in the rear lights. |
| Faulty cruise control actuator | On a car with a mechanical throttle drive (cable or rod), an actuator actuator is used to control the damper, which can fail. If the drive is broken, the system cannot control the throttle to maintain speed. | Check the wiring of the cruise control actuator and the actuator itself. Repair or replace the failed assembly. |
| Incompatible parts installed | If non-standard parts are installed during repair, on which the ratio of the speed of rotation of the motor and wheels depends (gearbox, its main pair or pairs of gears, transfer case, axle gearboxes, etc.) - the ECU may block the operation of the cruise control, because it sees an incorrect wheel speed that does not match the engine speed in the selected gear. The problem is typical for Renault and some other cars. | Three solutions to the problem: A) Replace the gearbox, its main pair or pairs of speeds with those provided from the factory. B) Set up the ECU firmware by linking a new transmission model. C) Replace the ECU with a unit from the car in which your current engine and gearbox combination came from the factory. |
Often due to problems with cruise control, automatic speed control is not available for the following reasons:
Frog limit switches, activated by the clutch and brake pedals, most often fail
- The brake pedal is used to disengage cruise. If the system does not see its limit switch or stop lamps, it will not be able to receive a shutdown signal, therefore, for safety, the cruise will be blocked.
- The ABS sensors on the wheels provide information to the ECU about their speed. If the signals from the sensors are incorrect, different or missing, the ECU will not be able to correctly determine the speed of movement.
Problems with the brakes and ABS are usually indicated by the corresponding indicators on the instrument panel screen. A diagnostic scanner will help clarify the cause of the error.
Autoscanner Rokodil ScanX
The most convenient for self-diagnosis is Rokodil ScanX. It is compatible with all brands of cars, in addition to showing errors and their decoding, as well as tips on what could be the problem. can also receive information from most car systems, and all that is needed, except for himself, is a smartphone with an installed diagnostic program.
Why is the adaptive cruise control not working?
In Honda cars, the contacts of two boards in the radar housing are often disconnected.
Adaptive cruise control is a more advanced system, closer to the autopilot. She knows how not only to maintain a given speed, but also to adapt to the surrounding traffic, focusing on the readings of the distance sensor (radar, lidar) installed in the front of the car.
Modern ACC systems are able to determine the position of the steering wheel, wheels, track road markings, and are able to steer using the EUR to keep the car in the lane when the road bends.
The main ACC malfunctions are:
- breakage or oxidation of wiring;
- problems with cruise control radars;
- brake problems;
- problems with sensors and limit switches.
If adaptive cruise control does not work, ACC-specific failures are added to the probable causes of failure of passive systems.
When the cruise control does not work, see the table below for the causes of ACC failures.
| adaptive cruise (radar) failure | Cause | What to produce |
|---|---|---|
| Defective or unlocked cruise radar | Mechanical damage or damage to the radar as a result of an accident, software shutdown after resetting errors during diagnostics and after repairing the car's electrics. | Visually inspect the integrity of the radar, mountings and wiring, check the electronics with a diagnostic scanner. If there are breaks and souring of the terminals, eliminate them, if the sensor breaks down, replace it and calibrate it. |
| Closed field of view of the radar | If the radar is clogged with mud, snow, or a foreign object (the corner of the license frame, PTF, etc.) gets into its field of view, the signal is reflected from the obstacle and the ECU cannot determine the distance to the car in front. | Clear the radar, remove foreign objects from the field of view. |
| Open circuit in the wiring of active safety systems and the brake system | There is no signal due to chafing of wires, oxidation of the terminals, deterioration of the pressure of the spring-loaded contacts. | Check the wiring of the electric drive (valve) of the brakes on the VUT, as well as the ABS sensors and other sensors. Restore contact. |
| Software error or ACC deactivation | It can occur with a software failure of the computer, a power surge in the on-board network, or a sudden power outage. | Diagnose the car, reset the ECU errors, activate the cruise control in the firmware in accordance with the instructions for the specific model. |
| Breakdown of the ACC unit | If the operation of the adaptive cruise control is controlled by a separate electronic unit, and it fails due to a power surge, short circuit and burnout of electronic components, or moisture ingress, the system will not turn on. | Replace ACC control unit. |
| Problems with VUT | For automatic braking in ACC mode, the VUT electric valve is used, which builds up pressure in the lines. If it is faulty (the membrane burst, the valve failed due to wear or moisture) or the VUT itself broke (for example, air leaks due to a cracked membrane) - cruise control will not turn on. During suction, problems also appear with uneven operation of the motor, errors are displayed on the instrument panel and / or BC. | Inspect the vacuum lines and the VUT itself, the braking solenoid valve. Replace the faulty VUT or electric brake drive. |
Cruise control speed limiter not working
Speed limiter - a system that prevents the driver from exceeding the speed set by the driver in manual control mode. Depending on the model, the limiter may be part of a single system with cruise control or be independent.
Diagnosing problems with the cruise control speed limiter
When installed as an option, activation and replacement of individual parts may be required. Therefore, sometimes there are situations when the speed limiter works, but the cruise control does not work, or vice versa. If the cruise does not keep the speed limit, or if the limiter is working, the cruise control does not turn on, the problems may be:
- in software;
- in the gas pedal sensor;
- in brake or clutch limit switches;
- in the speed sensor;
- in the wiring.
Typical breakdowns of the speed limiter and how to fix them:
| speed limiter failure | Why is this happening | How to fix |
|---|---|---|
| Defective speed sensor | Mechanical damage or short circuit. | Check the sensor by measuring its resistance. If the sensor breaks, replace it. |
| Breakage of wiring, souring of contacts. | Inspect and ring the wiring, clean the contacts. | |
| Misadjustment of the electronic throttle pedal | Due to misconfiguration, the potentiometer gives incorrect data and the system cannot determine the position of the pedal. | Check the potentiometer reading and adjust the pedal. |
| Incompatible gas pedal | Some cars have two types of pedals, distinguished by the presence of a limit switch to track the position of the pedal. If a pedal is installed without this sensor, the limiter may not turn on (typical for Peugeot). | Replace the pedal with a compatible one by checking the part numbers of the old and new parts. it may also be necessary to reactivate the limiter in the ECU firmware. |
| Problems with wiring contacts and fuses | The wire in the control circuits of the limiter has been frayed or the wire has come off or the contacts have acidified from moisture. | Inspect, ring the wiring and eliminate breaks, clean the contacts. |
| A blown fuse is often due to a short circuit or current leakage in the circuit after the insulation has been exposed. | Find and eliminate the cause of the burnout, replace the fuse. | |
| Disabling the OS in the ECU firmware | Software failure caused by a sudden power failure, power surge, complete discharge of the battery, unskilled intervention in the settings. | Reset ECU errors, re-enable the limiter in the firmware. |
| Pedal adaptation failed | Due to a software failure due to a power surge or power failure, the brake pedal may be released or the gas pedal setting may be lost, while the ECU blocks the activation of the OS. | Reset errors, bind the pedal, adapt it. |
How to find out why the cruise control is not working?
Identified cruise errors during diagnostics by the OP COM scanner
in order to find out why the cruise control system is not working, you will need:
- OBD-II diagnostic scanner, laptop, tablet or smartphone and software compatible with your car;
- multimeter to check wiring;
- a set of wrenches or heads for removing sensors.
To visually monitor the operation of the sensors, you may need an assistant who will see if the stops light up when the brake pedal is pressed. If there is no assistant, use a weight, stop or mirror.
Cruise control diagnostics is carried out in the following order:
What you need to know to diagnose cruise control: video
- Check the integrity of the fuse, lamps in the circuits of brake lights, turns, dimensions. If LED lamps are installed on a car with a CAN bus, make sure that the on-board electronics “sees” them or try temporarily replacing them with standard ones.
- Check for errors in the ECU memory with a diagnostic scanner. Directly problems with the cruise control system are indicated by error codes from P0565 to P0580. also often the cruise control does not work in case of problems with the brakes (ABS, ESP), the error codes of such malfunctions depend on the car manufacturer, and the breakdown of the limit switch is accompanied by error P0504.
- Check the limit sensors for the brake pedals, clutch (for cars with manual transmission), parking brake. See if the pedal moves the limit switch stem. Check the limit switches for correct operation by ringing them with a tester in different positions.
- If all lamps, wires, sensors (and cruise, and ABS, and speed) are working, the fuse is intact, check the cruise control buttons and see if the cruise control and / or speed limiter is activated in the ECU. If the cruise check reveals that the functions are inactive, you need to re-enable them. On some cars, you can do this yourself using open source software, but often you need to go to an authorized dealership.
Typical breakdowns of the cruise on popular cars
In certain models, cruise control often fails due to design flaws - unreliable or poorly installed sensors, weak contacts, etc. The problem is also typical for cars with high mileage and operating in difficult conditions. In such cases, the most vulnerable parts should be checked first.
Frequent breakdowns of cruise control in cars of a particular model, see the table:
| Car model | Weak point of cruise control | How breakage manifests itself |
|---|---|---|
| Lada Vesta | Position sensor (limit switch) of the clutch pedal | On Lada Vesta, cruise control simply stops responding to button presses. ECU errors are often absent. |
| Contacts of the electronic control system DVSm | ||
| Resetting data in the computer with a diagnostic scanner | ||
| Ford Focus II and III | Clutch position sensor | Cruise control on Ford Focus 2 or 3 does not turn on at all, or does not always turn on and works intermittently. ECU errors may light up, most often for ABS and parking brake. |
| Contacts of the button on the steering column | ||
| ABS module | ||
| Brake signals (handbrake, stop) | ||
| Toyota Camry 40 | Cruise control buttons in the steering wheel | On the Toyota Camry 40, in addition to cruise control, other functions controlled from the steering wheel buttons may be disabled. |
| Renault Laguna 3 | Cruise control activation fails after software failure or ECU firmware update | The Renault Laguna 3 cruise control system simply does not respond to button presses. It must be enabled using diagnostic equipment and software. |
| Volkswagen Passat B5 | Clutch pedal switch | If the buttons or the limit switch break, the cruise control on the Volkswagen Passat b5 does not turn on, without notifying it with errors. If there are problems with the vacuum drive, uneven operation at the idle is possible due to air leakage. |
| Buttons or steering wheel cable | ||
| Vacuum throttle actuator | ||
| Audi A6 C5 | Throttle vacuum pump (installed in the left fender liner) and its pipes | The cruise control of the Audi A6 c5 simply does not turn on, when you try to fix the speed with the button on the lever, you can not hear the relay at the feet of the front passenger. |
| Clutch pedal switch | ||
| Lever buttons | ||
| Bad contacts in the cruise unit (on a car with a separate KK unit located behind the glove compartment) | ||
| GAZelle Next | Brake and clutch pedals | If the buttons break (bad contact) and the limit switches become soured, the Gazelle Next and Business cruise control does not turn on, and there are no errors. |
| Understeering's shifter | ||
| KIA Sportage 3 | Cruise control buttons | Cruise control on the KIA Sportage does not turn on: its icon may light up on the panel, but the speed is not fixed. |
| Clutch pedal switch | ||
| steering cable | ||
| Nissan Qashqai J10 | Brake and/or clutch pedal switches | When you try to turn on the cruise control on the Nissan Qashqai, its indicator just blinks, but the speed is not fixed. If there are problems with the ABS sensors, an error may be displayed. |
| ABS sensors | ||
| steering cable | ||
| Skoda Octavia A5 | Understeering's shifter | When replacing the steering column switch, as well as after flashing the ECU, a power surge or a power failure on the Skoda Octavia A5, cruise control may be deactivated and the cruise control may not work. You can turn it on again using the diagnostic adapter and software ("Vasya diagnostician"). |
| Opel Astra J | Brake pedal sensor | In the event of a power surge or power outage on the Opel Astra, the brake pedal may come off and the cruise control does not work. The white indicator on the panel may be lit. The problem is fixed by learning the brake sensor via OP-COM and diagnostic software. With it, you need to prescribe the value of the pedal sensor readings in its free position. |
| BMW E39 | Clutch or brake pedal switch | BMW E39 does not react in any way to pressing the cruise control lever. |
| Automatic transmission selector position sensor | ||
| Throttle cable drive (motor) | ||
| Mazda 6 | Loop under the steering wheel | the car does not respond at all to an attempt to turn on the cruise control or the yellow indicator lights up on the panel. Please note that on older Mazda 6s, problems with idle (overshoot and drops) sometimes occur due to the tension of the cruise control cable, so some drivers simply disconnect it . In this case, it is necessary to return the cable to its place and adjust its tension. |
| Drive (motor) and cruise control cable | ||
| brake pedal switch | ||
| Mitsubishi lancer x | Brake pedal sensor | If the pedal limit switches break down, the cruise on the Mitsubishi Lancer 10 does not turn on, and there are no errors |
| clutch pedal sensor | ||
| Citroen C4 | Pedal limit switch | If the limit switch is faulty, the cruise on the Citroen C4 simply does not turn on. If there are problems with the buttons, their contacts, the cruise turns on irregularly, turns off spontaneously, and the “service” error appears on the panel. |
| Cruise control buttons |
Cruise control wiring diagram: click to enlarge
How to quickly fix a breakdown
Most often, a cruise failure is detected on the highway and it has to be fixed in the field, when there is no diagnostic scanner and multimeter at hand. If the cruise control suddenly stops working, first of all it is worth checking the main reasons for the failure:
- Circuit breakers. A blown fuse is caused by a sudden increase in current in the protected circuit. If the problem persists after replacement, you need to look for the cause.
- Lamps. Cruise control is automatically deactivated due to breakage of the stop lamps and the appearance of a corresponding error on the panel. On some car models (Opel, Renault, VAG and others), a lamp error can also light up if the dimensions or reversing lights break, so if the cruise control fails, you should check them too.
- Electronics Failure. Sometimes the cruise may not work due to a software failure due to a power surge on the on-board circuit. For example, the wiring contact came off on bumps, or at startup the battery charge dropped to a critical level. In this case, you can restore the operation of the cruise by dropping the terminals from the battery to reset the computer. Sometimes just turning off the ignition and turning it back on after a few seconds helps.
- Loss of contact. If on a rough road the wire came off the sensor or limit switch, the terminal flew off, then repairing the cruise control comes down to restoring the contact.
- Limit switch souring. If the limit switch, on the contrary, is frozen in the closed position, you can try to stir it up by shaking the pedal or by hand, or (if the sensor is collapsible) remove and clean it.
- Clogged radar. On cars with ACC, you need to check the distance sensor (radar) installed in the area of \uXNUMXb\uXNUMXbthe radiator grille and its wires. Cruise control may fail due to radar obstruction or poor contact of its connector.
Calling the contacts of the cruise control system with a multimeter
in order to make a quick repair of cruise control on a car on the road, always carry with you:
- spare lamps for brake lights, indicators of dimensions and turns;
- terminals for wires and electrical tape or heat shrink;
- a set of fuses of different ratings (from 0,5 to 30-50 A);
- a set of keys or sockets and a screwdriver.
A multimeter is never a bad idea to quickly check the wiring and sensor in the field. High accuracy of the device is not required, so you can buy any compact model. also, if problems arise along the way, a diagnostic scanner helps a lot, which, even in conjunction with a smartphone and free software like OpenDiag or CarScaner, greatly facilitates the search for errors and malfunctions.
