Having intermittent problems with cruise control on my car

ANSWER : Hello. This can be caused by a number of different issues. Most of the time this is caused by a bad brake switch. If the switch is shorting out, then it will cause the computer to think that the brakes are being applied, which turns off the cruise control. If the switch is fine, then it may have a bad speed sensor or the cruise control switch itself is bad.

One of the easiest tests I do is simply have someone drive behind me and see if the brake lights are coming on without touching the pedal. If it is, then you should replace the switch. If not, then further testing of the circuit has to be done. If you need to have this done, consider YourMechanic, as a certified mechanic can come to your home or office to diagnose your cruise control problem.

ANSWER : Hi, thanks for writing in. The cruise control uses some of the same sensor inputs the transmission uses and can indeed affect the transmission and cruise control. If the transmission is slipping then the cruise control may not control the speed steady. Have the transmission problem diagnosed and fixed then see if cruise control problems go away.

ANSWER : The unfortunate truth is the dealer is correct. What you are doing is in theory feasible but not common at all. I haven’t run across anyone who has done what you are doing and I have often wondered how such an endeavor might work. My point here is, I am not surprised the dealer isn’t sure because it’s likely they have never done this themselves. The dealer doesn’t set up the PCM (Powertrain Control Module) in the cars they sell. The manufacturer does and guessing what happened when a car is being built is not common knowledge.

Anytime you modify any car, there are always details such as this that you will possibly have to address. When you choose to modify a car, you are now the engineer. The simple answer is that I can’t tell you with certainty whether or not the PCM in your car has cruise control capability. The only way to find out is to allow the dealer to check in out. Independent shops might possibly be able to, but the equipment they have is aftermarket and not produced by Mazda. The electronic equipment the dealer has is. The dealer equipment will most likely be able to do what you need.

ANSWER : Hello,
There are a number of things that could make an engine noisy when starting up. Depending on the specific type of sound you are referring to, this will determine how to properly diagnose. If there is a bit of a hissing sound, this may be a sign of a vacuum leak. If this is more of a shrieking sound, this may be a sign of a worn out or out of adjustment serpentine belt. If there is a bit of a howling or growling sound, this may be a sign of a worn out or low on fluid power steering pump. A rattling or pinging sound may be caused by an ignition problem. An engine can ping (or knock) due to an improper combustion process. A "spark knock" is the result of combustion occurring too early. Early combustion can occur from carbon buildup inside the combustion chamber, a lean air/fuel mixture, and advanced ignition timing (spark plug firing too soon). A clattering type sound may be a result of improper lubrication in the valve train which could be a more serious problem and should be addressed as soon as possible. I would suggest having an expert from YourMechanic come to your location to diagnose and inspect your vehicle to ensure everything is in proper working order.

ANSWER : The issue you are having is probably due to an intermittent fault in the starter motor itself or a deficiency in the starter electrical circuit, for example a large voltage drop due to a poor ground or a high resistance connection. These issues can be readily diagnosed and resolved on a mobile basis if you request a hard starting diagnostic. If you request that diagnostic, the responding certified mechanic will get this resolved for you promptly. Based on Toyota’s Factory Service Manual, the battery should not be disconnected if the vehicle engine is running. The battery acts as a large resistive voltage sink and consequently taking the battery out of the circuit, while the alternator is still running, can create a voltage spike on the car’s electrical system which is not good for voltage sensitive components such as the engine computer. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

ANSWER : Hi there. What had happened is the wrong key set the security to the vehicle. This is to prevent the vehicle from starting with the wrong keys. Try removing the battery cables (+) and (-) for 13 minutes. During that time, put the original key in the ignition and turn it on. Activate everything in the car even though there is no power. Then remove the key and hook up the battery cables. The computer should have reset and reset the security. If the security is still being tripped, then I recommend seeking out a professional, such as one from Your Mechanic, to help you

ANSWER : Of course, don’t switch gears without being fully stopped, unless your Owner’s Manual or the manufacturer has alternative advice. However, the gear shift issue has no relation to the no-start problem you are describing. Inasmuch as you only have 6,000 miles on the car, the "constant on and off" that you believe has occurred is meaningless in comparison to the expected total vehicle service life. That is, assume what you perceive as "constant on and off", during merely 6,000 miles, might be equivalent to using the car "normally" for three years. A new car should be trouble free for at least 5 years, unless there is a defect, so your "constant on and off" is not a causal factor for any fault on the vehicle. What you might have is a defect in the ignition switch, or perhaps the immobilizer system, but if the problem is not in the switch itself, clearly there is an electrical problem.

If your vehicle is under warranty, by law the dealer MUST repair the issue you are describing within a prescribed time frame and number of "attempts", otherwise the dealer will run afoul of Federal and state Lemon Laws that give you very specific rights, and recourse (contact an Attorney; we are Mechanics, NOT attorneys). Consequently, if the vehicle is still under warranty, to save yourself money do be sure to seek a resolution from the dealer. If the vehicle is not under warranty, obviously a certified Mechanic from YourMechanic could identify the electrical fault and resolve this for you. If you want to go that route, please simply request a no start diagnostic -electrical system and the responding certified mechanic will get this taken care of for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

ANSWER : Hi there, thank you for writing in and providing a detailed description. I’d be happy to give my insight on what to do next.

I would make the same conclusion about the neutral safety switch. I think Pep Boys made the right call. I admit, I don’t like to call a part bad without being able to duplicate the problem, but anytime a customer states their car starts in neutral but not park, we replace the neutral safety switch. I can’t recall a time that this move was wrong.

The intermittent nature of your problem does’t change this diagnosis either. The same electrical connection can work one moment and not the next. Electricity works at the atomic level that we as humans can’t directly observe, which is why we have tools to do electrical testing. Your tow truck driver got it correct.

Hope this helps and best of luck! If you’d like help replacing your neutral safety switch, consider having one of our expert automotive technicians come to your home or office to do it for you.