Diagnosing AS68RC intermittent pressure switch/linear solenoid performance codes
Intermittent pressure switch codes on vehicles with the Aisin Seiki AS68RC transmission have been very difficult to nail down to one specific cause. The two most common pressure switch codes for this transmission are P0746 clutch pressure control solenoid A or linear solenoid A performance or “Stuck Off,” which also includes pressure switch 1 mechanical
Another needle in a haystack: Locating wiring problems
Paul Loch from Certified Transmission wrote a very good and detailed article for Transmission Digest in the March 2022 issue entitled “A Needle in a Haystack – Finding and Diagnosing Intermittent Problems.” The vehicle used for this article was a 2013 Ram 3500 6.7L equipped with a 68RFE transmission. Well worth the read. ATSG encountered
TCM trouble and the importance of being certain about parts replacement
It’s a tale as old as time. A vehicle comes in and, despite having been recently repaired by another shop, the vehicle owner’s concern is still present. In the case of this story, the vehicle came from a local shop we work closely with. The truck in question is a 66,000-mile 2006 Chevrolet Silverado 2500
Solving electronic control problems in today’s automatic transmissions
Special tools are often needed when diagnosing transmission problems and overhauling units.
Japanese CVT no-move conditions: Failsafe or defective TCM?
The Japanese Automatic Transmission Company produces a continuously variable transmission (CVT) known as the JF016/17E, which has been fitted behind 2.0L to 3.5L engines worldwide. Here in the United States, there is a light version called the CVT-8LT for 4 cylinder applications (JF016E) and a heavier version called the CVT-8HT for V-6 applications (JF017E). Nissan
Having a fit with a Honda Fit
A Honda Fit utilizing a GTAA continuously variable transmission will set a DTC after reaching about 30 miles per hour. When a scan tool is used to pull the code or codes set, a U0401-68 code appears in the scan tool with the explanation of it being a TCM failure. If a tech uses the
The diagnostic value of the scope
There was a time in my career when replacing a computer was touch and go. I always tried to do my due diligence and eliminate everything else as a possible cause before replacing the computer, but sometimes that wasn’t enough, and I would miss something along the way. That was long before I learned how
2016 Nissan Altima: What to do with a defective TCM
Nissan vehicles that produce Judder codes DTC P17F0 and/or DTC P17F1 in many cases will be a defective TCM. One sure way to know is to document and clear all codes. Then, keep the ignition on for a bit without the engine running. If the code returns, a defective TCM has been confirmed requiring a
Transmission control software: Know your terminology
When it comes to a post-rebuild adjustment of transmission control software, the terms flashing, re-flashing, programming, reprogramming and tuning often get used interchangeably. That said, each of these has a specific meaning and is used to address specific situations. To understand some of these terms we would have to break down the controller into three
Free ASE Webinar On Electronic System Diagnostic Strategies
The National Institute for Automotive Service Excellence (ASE) is hosting a free webinar for service technicians on Friday, March 12 at 4:00 p.m. ET entitled “Electronic System Diagnostic Strategies.”
6R140 Transmission Solenoid Strategy Code
When replacing solenoids, plan ahead and order the correct band numbers that came out of the transmission in the same location as they came out of.