A 2003 golf, equipped with a 01M automatic transmission, mileage of 50000km, cold normal, hot car upshift delay, when the engine speed rose to 2800r / min, barely into the 2 block; rose to 3600r / min , Can be promoted to 3 block.
Fault diagnosis and analysis
This car has been sent to the service station after the fault detection, due to no fault display, and the relevant sensor is no exception, was diagnosed as internal failure of the transmission. But the owner is not convinced of this diagnosis, so I check here.
After the car after the failure of the phenomenon was verified, the situation and the owner of the narrative is fully consistent. Routine inspection, the result is normal oil pressure, transmission oil no smell, oil transparent pure and no impurities, oil level meet the standard, automatic transmission control unit without fault code. But with VAG1552 view automatic transmission dynamic data flow, the transmission oil temperature rose too fast, combined with the car after the car did not delay the phenomenon of upshift failure, as follows:
1. Will the oil temperature sensor signal shift, to the control unit a false impression? The oil temperature sensor was then measured and the measured values were consistent with the values provided in the maintenance manual in each specific temperature range, indicating that the assumptions were not established. With the infrared thermometer to monitor the transmission radiator temperature, after a period of time after the transmission oil temperature rose sharply to 120 ¡æ, the failure followed again, indicating that the fault is caused by high temperature.
2. If the fault is caused by the high temperature of the transmission, what is the cause of the high temperature of the transmission? Possible reasons are: clutch, brake slip; bad lubrication inside the box; torque converter lock can not lock the clutch; radiator bad heat and so on.
Because the car in the rise and fall during the period did not appear to run empty and the engine speed steep rise and the speed of the phenomenon is not normal, you can rule out the clutch brake slip. If the box is poor lubrication, it will cause the planetary gear mechanism and bearing copper sleeve wear, serious will make the sun wheel bald teeth, but the car did not find these symptoms, it can also rule out the bad lubrication. If the torque converter lock can not be locked, it will lead to oil temperature rise, the test TCC lock the work of normal performance, observe the torque converter completely locked for a long time after the oil temperature remained at 120 ¡æ, and Do not drop, should be excluded from the torque converter work.
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