Failure phenomenon
(1) in the running, when the handle is located in the forward low gear (S, L or 2, 1) position, release the accelerator pedal, the engine speed to idle, but the car does not slow down significantly.
(2) when the downhill, the handle is located in the forward low gear, but can not produce engine braking effect.
Two, the cause of failure
(1) improper switch adjustment.
(2) improper adjustment of handle.
(3) 2 block forced brake skid or low block and reverse stop brake.
(4) Baotou North Heavy Duty Truck Parts control engine brake solenoid valve failure.
(5) valve plate failure.
(6) Baotou North heavy duty truck parts automatic transmission skid.
(7) computer trouble.
Three, fault diagnosis and exclusion
(1) for the electronic control automatic transmission, it is necessary to carry out the fault self diagnosis and find the cause of the failure according to the fault code.
(2) do road test to check whether there is any slippage in the automatic transmission. If there is a slip, the automatic transmission should be removed.
(3) if the handle is located in the S position when there is no engine braking effect, but the handle is located in the L position when the engine brake, indicating that the 2 stop forced brake skid, should be removed automatic transmission.
(4) if the handle is located in the L position when there is no engine braking effect, but the handle is located in the S position when the engine braking effect, indicating that the low gear and reverse gear brake skid, should be removed automatic transmission.
(5) check the control valve of the engine parts of Baotou North heavy duty truck engine brake, whether short circuit or open circuit; solenoid valve coil resistance is normal; after the power has no working sound. If abnormal, should be repaired or replaced.
(6) remove the valve plate assembly and clean all control valves. Valve core if the card can be polished after the re loading. If there is still stuck after polishing, should replace the valve plate.
(7) detecting the voltage of each pin of the computer. Special attention should be paid to the voltage of each pin connected to the throttle position sensor and the switch. If abnormal, should be further checked.
(8) try to replace a new computer. If the fault disappears, indicating that the original computer is damaged, should be replaced.