Scotts Valley Auto Repair

Call Us: (831) 438-0402
Mon - Thu: 8:00 AM - 5:00 PM
Fri: 8:00 AM - 4:00 PM

Questions & Answers

My check engine light is on, what could it be?

As a long time technician, I have seen the confused look given to me when I tell a customer that there are hundreds of possibilities that can be the cause of their check engine light. They almost always ask “How much will it cost to fix?”, or “How long can I drive with it like this?” Today’s vehicles have very sophisticated feedback systems. The PCM/ECU is constantly monitoring and adjusting numerous systems at the same time. Some of those systems are related to the engine's emission control system, engine management, and powertrain management systems. One component of the transmission system is the torque converter clutch, or TCC. A TCC is used to lower fuel consumption, and it also aids in lowering transmission temperature. The transmission's torque converter has a clutch built into it. By locking the converter clutch to the transmission's input shaft, your ratio is 1 to 1. That is, there is no slippage in the converter. As you are varying the throttle position slightly, the engine RPM stays fairly steady. In some vehicles, if the throttle is returned to a closed position, the PCM/ECU may disengage the TCC. Some other things that may disengage the TCC include brake switch pedal pressure or wide open throttle driving. Since the PCM uses the TCC to aid in fuel economy, it will monitor its operation and advise the driver that there is an issue with the TCC system. This is done through the check engine light warning system.

A faulty TCC system can cause a number of issues. A slipping TCC will cause increased fuel consumption, excessive converter temperatures, and internal transmission failure due to heat stress and contamination from the effects of slippage. Some drivers may notice an increased engine speed, mainly at freeway speeds. A properly functioning TCC system can cause freeway speed engine RPM to be approximately 250 to 450 RPM lower while the TCC is engaged. Various other transmission issues can trigger a check engine light to become illuminated. Some are gear ratio codes, or slippage codes. These codes are sometimes accompanied by harsh shifts or harsh engagements. Transmission over temp conditions can also cause a check engine light.

Because automatic transmissions are the most technically complex systems on an automobile today, it requires transmission specialists to be highly trained in multiple areas. It will be worth your while to bring your vehicle into our transmission shop for a check engine light diagnosis. Many general auto repair shops replace components and transmissions unnecessarily because they don’t have the training or experience to diagnose transmission symptoms properly. So remember next time your check engine light comes on, bring it to our shop. We will run a free fault code test to see if the check engine light is related to and if it is safe to drive.

Q: My transmission leaks. Should I be worried about it?

A: Yes, even a minor leak, if left unrepaired, can lead to major problems. Leaks usually require a minor repair to fix, which can save you time and money.

Q: My transmission has started shifting erratically. Do I need an overhaul?

A: Could be, could not be. Most late-model transmissions are computer-controlled. Numerous sensors can cause a transmission to misbehave. It's important that a diagnosis be performed to confirm what specifically is happening so that small problems now don't turn into large problems later.

Q: My Service Engine/Transmission light came on. Is this a major problem?

A: Could be, could not be. Most late-model transmissions are computer-controlled. Numerous sensors can cause a light to come on and cause shifting problems. With dozens of codes, and hundreds of moving parts inside your transmission, it's important that a proper diagnosis be performed to isolate what your vehicle issues might be.

Q: My transmission fluid smells bad. Should I worry about it?

A: Possibly. Transmissions need to be serviced regularly as a normal part of maintenance. The fluid can break down over time and cause it to smell different, a strong burn odor may be an indication that the transmission may be overheating. Catching this as soon as possible may prevent a catastrophic transmission failure costing you thousands of dollars.

Q: Are all transmission repairs expensive?

A: No. In fact, over half the repairs we do on vehicles are minor. However, if a transmission starts to have problems, it should be checked right away to prevent a major expense.

Q: How long do repairs take?

A: Minor repairs can usually be done in a few days, depending on parts. Larger repairs vary depending on parts, the amount of damage, and how busy the shop is.

Q: I had my code pulled and it says it's a bad solenoid, how much does that cost to repair?

A: This is probably the most misdiagnosed code in the general automotive shop industry. Any technician that is specifically trained in the transmission field knows that a solenoid code does not always mean a solenoid is bad. As sophisticated as the vehicle's computer can be, they can also be extremely vague or only get a glimpse of the actual issues. The computer systems job is to attempt to trigger a code for the most likely cause of the issue but their information is limited to what they can monitor. I have seen thousands of times that another shop has diagnosed a bad solenoid and found that the transmission had a missing gear or severe metal contamination which is what shorted the solenoid. It's very important that a transmission trained tech inspect your vehicle to get all the information prior to replacement of any solenoids or sensors to ensure money is not wasted.


Scotts Valley Transmission & Auto Care is committed to ensuring effective communication and digital accessibility to all users. We are continually improving the user experience for everyone, and apply the relevant accessibility standards to achieve these goals. We welcome your feedback. Please call Scotts Valley Transmission & Auto Care (831) 438-0402 if you have any issues in accessing any area of our website.