Delivering the Goods - January/February - 2019

Diagnosing the DPS6: Knowing the Good Helps You Identify the Bad!

The DPS6 transmission in Ford Fiesta and Focus models has been around long enough for us to accept that they aren’t going away. In fact, this type of transmission is preferred for high-end, high-performance vehicles.

For argument’s sake, consider this an entry-level unit. It’s a direct-shift gearbox (DSG) consisting of a dual, dry-disc clutch assembly, fully controlled by an external transmission control module (TCM). Bill Brayton wrote an article on the inner operation of this unit in the June 2014 edition of GEARS.

For reference purposes, Ford also refers to this unit as the powershift transmission. Borg Warner, the manufacturer, designates it as the 6DCT-250. These transmissions are becoming more abundant in the U.S. and other markets. Since they operate differently than any conventional automatic transmission, they have a unique feel and function. That being said, let’s take a real-world look at the DPS6.

What Does Good Look Like?

One major concern with these units lies with the customer’s perception of how the vehicle feels during normal operation. On-off throttle operation, coastdown and low-speed noises, and kickdown are common areas of concern.

As a technician, it’s extremely important that you know what this unit is supposed to feel and sound like. If you aren’t familiar, go to a dealership and take one for a test drive. Some very noteworthy oddities are considered normal for these vehicles. Despite the quirkiness of this unit, it delivers respectable performance in an economical package.

One thing to keep in mind: This is a manual transmission that shifts automatically! If you expect more, you’ll be disappointed. On the other hand, it has some unique operating features that make it feel more like an automatic transmission.

  • Hill Mode/Launch Assist: Sensors detect when the vehicle operates on a grade. The computer system applies the brakes when the driver is either in drive going uphill or in reverse backing up a grade. The brakes remain applied until you let the clutch apply enough for the vehicle to move in the intended direction while you switch from the brake to the accelerator pedal. Once you’ve achieved adequate torque transfer, the computer releases the brakes.
  • Neutral Coastdown: This function engages once you apply the brakes. Under normal driving conditions, the transmission shifts to neutral to prevent trailer hitching and improve overall driveability and fuel economy.
  • Low-Speed Driving/Creep Mode: This function incorporates braking along with precise clutch control to produce drive quality similar to an automatic transmission. The computer controls torque transfer and brake application in forward or reverse to achieve the smoothest operation. Once you’ve reached an appropriate speed, the function completely releases the brakes.

Unusual noises are a typical customer complaint. But this unit is naturally noisy. There are high-speed, high-torque electric motors moving gearbox and clutch components in fractions of a second. If you were to attempt to perform the same functions with a conventional manual transmission, you’d be making noises too! Here’s what to expect:

  • Double clicking metal sounds: Noticeable when road and engine noises are low or with the windows down. This is most noticeable on the 1-2 upshift and the 3-2-1 coast downshift. This comes from the shift forks and synchronizers operating.
  • Coastdown whine: Expect this while coming to a stop at low speeds.
  • Clicking sounds after you’ve turned the engine off and immediately after the engine starts: The TCM cycles the clutches off to ensure a safe engine restart.
  • Low speed grinding noises: You may notice a slight grinding noise at around 2 MPH. This is due to normal bearing loading and doesn’t affect the transmission’s durability.
  • Reverse gear whine: This is something you might expect from a manual transmission, but it isn’t as common — or as loud — as in a traditional manual transmission.

When you replace a clutch, you have a “green” clutch break-in period. During this time, you may notice additional noises and driveability problems. These conditions are normal:

  • Takeoff shudder; vehicle launch is shaky.
  • A harsh shift until the transmission reaches operating temperature.
  • A rattling noise similar to a loose catalytic converter shield. Expect this to be more common between shifts at light throttle.

Now that you know what’s good, let’s look at the issues associated with this unit.

Common Issues

Clutch Actuator Motor Issues — This is very common. You need to understand how the computer monitors actuator operation and sets codes to simplify your diagnostic process.

The DPS6 transmission uses two clutch actuator motors, one for each clutch. You can service them without removing the transmission (figure 1).

Each motor contains a clutch position sensor, which is part of the motor and not serviceable separately. The clutch position sensor provides precise clutch position feedback to the TCM for accurate clutch control. These motors are identical and interchangeable, which means you can swap them to see if you have a bad motor, sensor, or other related component.

Depending on the codes set, you can simply swap the clutch actuator motors and see if the system sets a different code (figure 2). If it does, you can condemn the clutch actuator motor/ sensor. If the code doesn’t change, you’ll need to diagnose the circuit or mechanical clutch components associated with the code.

For example, if the system sets code P090B — Clutch B Actuator Control Circuit Performance — visually inspect the harness from the TCM to clutch actuator motor B for any obvious signs of damage. If you don’t find anything, swap clutch actuator motors A and B and retest for codes.

If you get code P0901 — Clutch A Actuator Control Circuit Performance DTC — the clutch actuator is bad; replace it. If code P090B remains, diagnose the system according to circuit pinpoint test procedures found in Ford factory manuals or other aftermarket sources.

DPS6 owners may learn to love their vehicles despite the quirks, and choose to hold on to them for as long as possible only to endure other unforeseen issues. Among the most common complaints are when the vehicle intermittently won’t start, won’t move, and stores a variety of DTCs.

Won’t Start, Won’t Move With or Without Codes

When this vehicle comes into your shop with any combination of these issues, your first instinct might be to send the customer to the dealership or contact your nearest religious professional to figure out why you still work on transmissions.

But there’s hope. Remember, this vehicle worked correctly at some point, so you have the opportunity to find a pattern failure to put it back into good working order.

One very common failure area related to all of these complaints starts at a familiar component: the battery. A bad battery is often accompanied by code P0606 — TCM internal failure.

Before you condemn the TCM, transmission, or any related component, verify that you have a fully charged battery. Ford’s 2.0L engine will crank over without a hint of drag with a weak battery, even on a cold day. So start with a battery test, clean the battery terminals, clean and reset the grounds near the battery — very important! — then retest the vehicle.

Other important areas to check are the harness and TCM connector, specifically the harness from the TCM to the ECM. This harness often rubs through; you’ll need to repair it before going further. Use a borescope camera with a flexible head to make this process easier, faster, and more thorough.

If someone handled the TCM connector, it may be damaged. It has a cam-lock mechanism to secure it once it’s seated properly. Engaging the cam lock when the connector isn’t fully seated will damage the cam-lock mechanism and possibly the TCM and connector terminals. Motorcraft has a replacement connector available (figure 3).

If there are no codes, the engine won’t start or won’t move, and the battery tests good, try scanning the vehicle using the OBD generic function of your scan tool. There may be communication codes or codes that your scan tool can’t retrieve in vehicle ID mode.

Try a different scan tool. If you’re using an aftermarket tool, you may not be seeing the whole picture. These vehicles are usually very good at sending DTCs that point toward the problem area.

Next, check your scan tool data. If the parameters for items such as clutch position, TR sensor (range sensor), or speed sensor operation are incorrect, they may not set codes immediately, but they can cause any of these conditions. Most aftermarket scan tools can perform a special speed sensor performance test in the Transmission> Special Functions area.

If the problems persist, refer to Motorcraft bulletin TSB 16-0129. It’ll guide you through a procedure to determine whether you need to reprogram your existing module or replace and reprogram it. Check for information concerning factory warranty coverage before proceeding.

Clutch Shudder — Many earlier units had clutch shudder issues caused by oil on the clutch lining. This remains a problem, but it isn’t as frequent now. The source is usually oil leaking past the input seals (figure 4). Always inspect and service these seals when installing a new clutch assembly. Another source of oil leaking into the bellhousing is from the crankshaft boltholes. If you remove the flywheel bolts, always apply sealant when reinstalling the bolts or engine oil may wick past the threads into the bellhousing. The crank boltholes are drilled all the way through and are exposed directly to the engine crankcase oil.

Even though oil from the crankcase doesn’t pose a direct threat to the clutch lining, it can cause the engine to run low on oil, and eventually the accumulated oil can get blown up onto the clutch.

Relearn Functions

Whenever you replace the clutch, TCM, or transmission range sensor, you need to perform three relearn functions:

  • Shift Drum Relearn
  • TR Sensor Relearn
  • Clutch Adapts

Most aftermarket scan tools are capable of performing these functions. The Ford IDS tool or an equivalent J2534 pass-thru device can also perform them.

After you’ve completed these relearn functions, check the TCM for codes, clear them, and perform a relearn test drive (figure 5).

Considering new technology, educating the customer may be just as important as educating yourself on proper operation of these vehicles. As the action hero toy G.I. Joe said, “Knowing is half the battle!” In this case, knowing what good looks and feels like can save you, the customer, and the shop time and money.