The effects of the global semiconductor shortage on new-vehicle availability, and industry profits, are well known. But an even more significant effect of the “chip” shortage has been going on under the media radar: the shortage of electronic service parts for vehicles already in use. Scores of cars and trucks have been rendered inoperable because the OE replacement electronic modules they need are not available.

The author is among the many thousands of vehicle owners left stranded “without wheels” by this situation. In my case, it began with the DPS6 dual-clutch transmission of my 2011 Ford Fiesta failing to execute a shift. The car’s on-board diagnostics (OBD) had posted a transmission malfunction notice on the SYNC digital display.  A Check Engine light and a wrench symbol, indicating need for service, appeared on the instrument cluster display. A check using a scan tool showed a P0606 code (internal failure of the transmission control module (TCM).  The car’s electrical connections were found to be intact and the harness was in good condition. All signs pointed to the need for a new TCM.   

Ford technical service bulletins noted the company is covering installation of a replacement TCM along with a software update for cars up to 10 years old and 150,000 miles showing on the odometer.  The TCM is part of the vehicle emissions control system, so Ford specifies a new OE module for cars less than eight years old or with under 80,000 miles on the odometer (the emissions control parts warranty).  In a rare move, for cars beyond 8/80, Ford also is authorizing “a used Ford Motor Co. TCM, a refurbished original Ford TCM, or an aftermarket TCM that will successfully complete the required Ford software updates.”  There is a $400 limit on any of these alternatives.

Although my Fiesta was just past the 10-year extended warranty, the odometer reading was well below the 150,000-mile limit on mileage. Ford agreed to cover my car and once the dealer formally verified the issue, Ford would put me on the waiting list for the needed module.

Because of the worldwide chip shortage and overall supply-chain mess, the modules are backordered. And I’m among the 11,000 vehicle owners who reportedly are waiting for a module.  My local dealer said he had customer cars parked at his lot for over a year due to the shortage. He said that if he got a module it would go into one of those cars. And it had been much longer than that since, he added, he had seen a new or approved alternative module. Eventually, Ford told me it could not get me a module off the waiting list.

Hunting a replacement TCM
How could vehicle owners wait so long to get their vehicles repaired? Ford has a free rental deal and generously offered to enroll me in it.  But unlike owners of vehicles under warranty, I would have to pay for the rental and send Ford a request for reimbursement following repair. Additionally, the dealer said there were price limits and there were no vehicles available in my area for a price that would be covered completely.  I might have to lay out perhaps $10,000, maybe much more, and likely be reimbursed for far less. 

At that point I had to find an alternative module somewhere.  Independent service garages told me they always prefer new OE electronic modules anywhere on a vehicle because the OE units offer assurance of proper fit, electronic compatibility, local availability and “normally-it-will-work” assurance.

But I needed my personal mobility back. With new OE electronic modules unavailable, an alternative was needed.  Many repair shops already had been forced to seek one and the pickings were slim. So, I went to plan B: checking eBay and Amazon. Those sources showed many TCM listings, some for as little as $250. But the low-cost TCMs I saw were for non-OE modules shipped from China. If they didn’t work, they’d have to be sent back to China, with hope for a refund.

Although the Fiesta had been manufactured in nine countries including China, the one I own was built in Mexico. Its module likely was developed in the U.S. or Germany, where the car was engineered. I realized there was no guarantee of the electronic compatibility or physical fit of the Chinese modules.  This was important, as at best it would have to be reprogrammed with U.S. OE software, because all modules I saw listed were for the Focus with a 2.0-L engine, not the 1.6-L in the Fiesta.

There had to be an OE module available somewhere, I reckoned. And indeed, some were advertised on eBay.  But the prices being listed for a new U.S. module were over $1000 — word obviously had gotten around about the waiting list for TCMs! Of course, the cost of reprogramming and remove-and-replace labor for the job would make the total price unacceptably high. I found a few modules advertised for around $500, but there was no indication where they were made. Taking a chance on them was risky, as their ads warned “no returns,” and the modules were listed for “Focus and also fits Fiesta.” That meant they would have to be completely reflashed (if that would work), adding to the expense.

I also checked salvage yards for a used OE module and located a few. But their conditions were unknown. And with no warranties, no returns, and $600-and-up prices, they were unacceptable risks.

Shifting restored!
There are reputable American companies that “remanufacture” automotive electronic modules. The optimum choice was from Colmar, Pennsylvania-based Dorman Products, which supplied a Fiesta-specific TCM. This module did not require immediate reprogramming and was priced at under $300.  The module did require an adaptive learning drive cycle to “train” it to shift the transmission smoothly (or as smoothly as the notoriously clunky DPS-6 will shift). Adaptive learning is a function typically found on professional scan tools –just plug it into the OBD connector and follow the prescribed drive cycle. It’s a half-hour procedure.

The TCM cores that Dorman receives are serialized, checked for repairability, then disassembled and cleaned. Dorman replaces circuit boards, motors, and other internal components — even functioning but failure-prone parts —  that need to be replaced. Terminals are soldered, and the module is then reassembled with new seals and tested on a vehicle simulator that includes the transmission.  There’s a limited lifetime warranty on Dorman remanufactured electronic modules, so installing one seemed relatively risk-free.

Result: Installing the “reman” Dorman TCM restored my Ford’s basic shifting function and after a drive cycle it was back to normal, with only software updates possibly needed.

Longtime SAE contributing writer Paul Weissler is a veteran technology journalist specializing in vehicle diagnostics and service. He also serves on SAE’s HVAC Technical Standards committee.