A mileage of about about 120,000 km, automatic transmission configuration 01V B52.8L Passat sedan. The car can not shift automatic transmission due to plant maintenance. After receiving the car: the road test and found that the car is always locked in 4th gear. Read diagnostic trouble codes using 5054a found P0753N88 switch or circuit breaker connected to the solenoid valve poor and can not afford to clear. In 01V automatic transmission, a total of seven solenoid valves, wherein N88, N89, N90 of the switching solenoid valve, N215, N216, N217, N218 of the linear solenoid valve, N215 main oil pressure regulator valve, N218 is the torque converter lock stop control solenoid valve, N216 and N217 solenoid valves control the C and G brakes brakes, while switching solenoid valve N88, N89, N90 by logical combination to control the other clutches and brakes. Can be clearly seen from the table, when all the solenoid valves do not work, the automatic transmission is locked in fourth gear. Based fault codes tips on N88 solenoid valves and circuits. N88 solenoid valve coil resistance is around 30a, from the ECU to the solenoid valve harness resistance is 0.10, but not on the ground or shorted to the cathode, is still the problem of N88 solenoid valve harness? Later, the N88 and N90 solenoid valve solenoid valve reversed, the fault persists. Line is not unusual, the solenoid valve is not a problem, is it a problem ECU (J217) of? Finally, replace the J217, after re-encoding match, failure to completely ruled out. It seems that the failure was due to the negative line N88 solenoid valve open circuit occurs in the ECU control circuit triggered Ground fault codes, because N88 solenoid valve does not work properly, thus affecting the normal shift automatic transmission, the transmission ECU had to be Lock Control, to prevent transmission damage.
Fault representation: A 2009 models FAW – Volkswagen Magotan sedan 1.8TSI, say users, speeding up the road in the car bad, EPC warning lamp lights up on the exterior. Failure analysis: The use of fault diagnosis instrument VAS 5051 testing, the engine control unit stores the fault code 08852 (fuel pressure regulating valve N276 open circuit), the fault code is a permanent failure, can not be eradicated. Fuel pressure reading data stream 01-08-140 Group 3 area, appeared at idle is 700kPa, and standardized value should be around 4MPa, the results illustrate the detection system can not establish a high-pressure fuel. Volkswagen PQ46 channel selection Magotan sedan equipped with electronic fuel injection engine, fuel is installed on the high pressure fuel pump through the pressure conditioner N276 to recuperate. In the injection process, based on the engine control unit calculates the starting point of supply to the fuel pressure control valve N276 to send commands to make it pull, at the moment the needle needle stretched spring force to overcome the forward movement, the inlet valve in the stretched spring is closed under the force. Followed by the upward movement of the piston pump, the hydraulic pump chamber to establish when the pump chamber is higher than the hydraulic oil in the fuel rail, forcing the valve open, the fuel will be pumped into the fuel rail. Constitute a stable high-pressure fuel pressure in the fuel rail pressure sensor and to identify the signal to the engine control unit, after reading the data stream 01-08-140 Group 3 zones show we can analyze the pressure hypertension is not a normal build. Based on the above analysis of the process of establishing high-pressure fuel, resulting in high-pressure fuel supply system can not establish a cause includes: camshaft drive equipment damage, high pressure booster pump failure, electronically controlled high pressure booster pump and engine control unit fault line fault. But contact pressure regulating valve fault code hints N276 circuit, it is necessary to fulfill the primary VAS5051 components through self-diagnosis function on the N276 line fuel pressure regulating valve quiz, find fulfillment in contact when measured from diagnosis N276 shell without any repercussions, but also not heard by the engine control unit according to a certain frequency manipulation pull the “click” sound, from the moment of diagnosis interface VAS5051 show closed loop system activation and fulfillment. So start the engine control unit to determine the presence of manipulation can not fault, the fault should be locked in the N276 fulfillment lines. N276 based conditioner control circuit, conditioner N276 total two terminals. Job control T2gz / 2 terminal to the terminal of the engine control unit T60ya/19, to withstand manipulation unit; T2gz / 1 SB17 fuse terminals through the high pressure pump control relay adapter J49 engine 87 feet from the power supply for the main relay signal. DTC then contact tips can analyze the reasons included: N276 internal circuit breaker; N276’s T2gz / 2 terminal to the engine control unit T60ya/19 circuit breaker between the terminals; N276’s T2gz / 1 terminal to the engine high-pressure pump control relays J49 87-pin circuit breaker between the terminals; J49 relay their own circuit breaker; J49 peripheral power supply circuit breaker.Buy cheap and quality vas 5054a on obd2works Unplug the wiring harness connector N276 to T2gz / 1 for the measurement point detection when burning conditions for the normal engine control waveform negative trigger waveform, which is between the N276 wireless clarify the T2gz / 2 terminal to the engine control unit T60ya/19 terminal road circuit representation. To N276 of T2gz / 1 terminal point of measurement, testing without burning conditions in the supply voltage, which can be inferred N276 power supply circuit presents a circuit failure. Measuring the high-pressure pump control relay J49 87 feet of the terminal to N276 T2gz / 2 foot line is normal, it is possible to conclude that the fault is internal or the external power relay J49 reason. In the middle of the detection relay J49, 30 measure the normal supply voltage terminal 85 by the pin from the main relay control SB23, measured normal to the power supply 15. Further manipulation of the coil resistance measurement J49 relay (85 feet and 86 feet) of 82Ω, cf norms resistance is normal, the normal start testing components, but the lack of electricity power lines. In order to pursue this issue, open relay housings, gear survey in the incineration of two relay contacts to fulfill client does not pull clarify the relay coil control when operating inside virtual connection can not supply the required performance of the loop pull closing force. Replace J49 relays, fault code 08852 can be eradicated. At the moment then use VAS5051 quiz function, into the engine system components to perform self-diagnosis N276, N276 can hear frequencies in accordance definitely pull of “clicks” to clarify the engine control unit to control the rehabilitation of the normal high-pressure booster pump, now reads fuel pressure at idle 140 jobs for the group appeared 4MPa, thorough treatment failure so far. Repair Summary: Needs to clarify that, with respect to Magotan sedan, the fuel can not establish a high-pressure high-pressure booster pump failures are basically caused by internal mechanical failure, which is usually the pump piston is catching only point I can not be quite camshaft cylinder through Useful trip lever drive, then not required to establish the appropriate hydraulic injection. Engine control unit monitors the operation of hydraulic scale values of tolerance, then summed for high pressure booster pump without electronic control circuit fault code identifying the logical analysis, and therefore will show fault code 08851 (fuel pressure regulating valve N276 mechanical failure) fault code storage . And in this case due to the associated control circuit breaker, resulting in a fault code stored in 08852, we can see the same appearance, but the causes of failure, but worlds apart, which prompted our failure in the maintenance of electrical control, we must abide by all the confirmed detection processes analysis, targeted to deal with failure to prevent the empirical errors.our shop obd2works.com supply VAS 5054A