What are the symptoms of a faulty automatic transmission computer?
3 Answers
Here are specific manifestations of a malfunctioning automatic transmission computer: Difficulty in shifting gears: After engaging first gear, pressing the clutch fails to shift gears properly, whether upshifting or downshifting. Gear slipping: In a normally functioning transmission, when the vehicle is stationary, the gear should remain in the designated position or the computer-specified gear within a certain RPM range until the computer initiates a gear change. However, with gear slipping, the vehicle can spontaneously jump out of the drive gear into neutral. Gear lock: The transmission enters protection mode. The computer can detect faults in the transmission. The more advanced the vehicle, the stronger the computer's detection capability. In such cases, the computer locks the transmission in third or fourth gear to alert the owner to seek repairs. Transmission damage: The secondary oxygen sensor will fail to provide accurate data to the vehicle's computer, leading to either excessively lean or rich fuel mixture. A lean mixture can cause ignition difficulties, weak driving performance, engine backfiring, etc., while a rich mixture increases fuel consumption, incomplete combustion, and severe carbon deposits in cylinders and spark plugs. When this fault occurs, the engine warning light should illuminate, and immediate inspection and repair are necessary once detected.
I encountered this issue last time. The most obvious sign of a faulty transmission computer is that gear shifting becomes extremely erratic. Normally, it should shift smoothly, but when the computer malfunctions, you suddenly experience violent jerks, as if someone kicked the car. What's even more annoying is that sometimes it refuses to upshift when it should—the tachometer revs up to 3,000 or 4,000 RPM, but the speed won't increase, and fuel consumption skyrockets. The dashboard usually lights up with a yellow warning light, sometimes showing the engine fault light or a specific gear indicator. The worst part is when it suddenly locks into a gear, leaving you stuck in third with no shifting, crawling at just 60 km/h. Once, my car even stalled for no reason. So, if you notice these symptoms, get the fault codes read immediately—if the computer is faulty and left unrepaired, driving further can damage other components too.
The symptoms of a faulty transmission control module are quite obvious. First, there will be abnormal gear shifting while driving, such as strong jerking during downshifting or completely incorrect timing for upshifting. Secondly, the dashboard will illuminate warning lights, usually the yellow engine light or gear position indicator. Then, the vehicle may enter a protective mode, limiting it to a specific gear and preventing shifting, allowing only low-speed driving. Sometimes, there will be a mismatch between engine RPM and vehicle speed, where pressing the accelerator to the floor doesn't increase speed. Starting issues are also common; a malfunctioning computer can occasionally cause difficulty starting the engine or immediate stalling after startup. These conditions are often accompanied by abnormally high fuel consumption and transmission overheating warnings. It is recommended that owners stop and inspect the vehicle immediately upon noticing these signs to avoid damage to the transmission itself.
