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Hello, I have problems with a KIA CERATO/FORTE TD 2011, problem is that the transmission is locked in limp mode. It does not need to run, just start it and the transmission is stuck in 3rd gear idling. DTC present Multiple P0760, P0765, P0755 and P0626. I have done everything to troubleshoot this issue, I believe I have a bad ECU/TCU in this case. Because, I have checked the status of the shifting solenoids, all of them have a resistance value in specs, 3.2Ohms +/-2. I have done a current draw test on all of them and each of them draw about 4amps at battery voltage. TCU sends the voltage to the solenoids but this voltage is only present on the harness connector being disconnected from the valve body connector on the transmission housing. As soon I plug the connector the 12 volt will drop to "0.012"volts. So There is power when it is onloaded. It seems like the TCU is sending a weak power and it can not drive the solenoids. Another service center checked this car and they call out a bad valve body and told the customer to buy the whole valve body. I doubt that the problem is in the valve body. Any advise will be appreciated. Thanks you!!
Hi. Test light will glow bright!! when activating the solenoids. No clicking sound. Only the VFS Line Low and High solenoid can be heard. The rest are Pulse Wide Modulation Solenoids, they will not click when activating. All solenoids are connected to ground and the other sides is driven by the TCU signals. Test light connected to battery positive, light will glow very bright. This problem is almost always present, but it can work fine for a while and go bad again. When driving it can jum out of speed or start slipping suddenly an dact like it is in neutral but the instrument panel kepps showing "D". When put in sport mode at idle the display shows 3 shifting the lever to 2nd gear in sport mode does not do anything, it will stay in 3rd gear. Idling and put in D, while depressing the brake pedal you might feel the like it popped out of gear. the torque pressure is gone and might come back after a while. But always in 3rd gear.
Yes I have made some checks on tie TCM, This car Has the ECU and TCU in one unit attached to the air cleaner assembly engine compartment. I have already called out a bad ECU/TCU. The customer took the car to another service center, they stated that the problem is NOT the ECU/TCU but the whole valve body should be replaced!!! I am afraid they will be spending money on the valve body assembly without fixing the car. I will appreciate some advice of how to rule out that the TCU is really bad. So far I know its not usual that valve body fails!! but the shifting solenoids will. But I have checked all of them by resistance and current draw and they look fine!
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