The Nissan Teana car with a mileage of over 213 thousand km in 2006. After the car is peddied, it has no response on the accelerator pedal. The engine can keep idle and the engine fault lamp is long. Fault diagnosis: 2004-2007 years Dongfeng Nissan Nissan Factory Maintenance Manual 1) by asking the customer, this car is in other repair shop, because the right front accident after the repair of sheet metal spray, take the car after the car pedal after the accelerator pedal no reaction, engine fault lights long, and after the fire is still long light from the new vehicle. Outside maintenance can not solve the problem of failure, the trailer comes to our shop. The car does not install any accessories. 2) start the engine, start the normal, the car pedal after the car does not respond, the engine can keep idle running, the battery voltage 13.8V normal, engine fault light long. Related data: 3) DTC confirmation, turn the ignition switch to OFF position for more than 10 seconds, use the CONSULT-III diagnostic instrument to connect the vehicle diagnosis joint, turn the ignition switch to the ON position, wait for at least 2 seconds, start the engine, the idle speed is more than 5 seconds, and the self diagnosis function on the CONSULT-III diagnosis instrument. The following fault code is read to the engine: when the P1122:ETC power circuit 0 (current) P1126:ETC motor power 0 (current) detects the above fault code, the ECM enters the safety failure protection mode and the MIL becomes brighter. The engine operation under the safety - failure protection mode: ECM stops controlling the electronic throttle control actuator, and the throttle is kept at a fixed opening (about 5 degrees) through the back spring. The fault condition is also in line with the operation mode of safety failure protection mode. 4) consult the maintenance manual EC-219. If DTC P1122 and DTC P1121 or 1126 display at the same time, the fault diagnosis of DTC P1121 or DTC P1126 should be first carried out. 5) DTC P1126 throttle control motor relay circuit opens. The power supply of throttle control motor is supplied to ECM by throttle control motor relay. ECM controls throttle to control ON/OFF of motor relay. When the ignition switch is transferred to the ON position, ECM sends the ON (closed) signal to the throttle control motor relay, when the battery voltage is supplied to ECM. When the ignition switch is transferred to the OFF position, ECM sends the OFF (disconnect) signal to the throttle control motor relay, when the battery voltage is not supplied to ECM. Switch the ignition switch to the OFF position and check the ECM port 104 with the earth voltage 13.9V=. Switch the ignition switch to the OFF position and check the ECM port 3 with the earth voltage 0V=. Switch the ignition switch to the ON position. Use the voltmeter to check the ECM port 3 and the earth voltage is 0V= (normal should be the battery voltage). Switch the ignition switch to the OFF position, disconnect the ECM harness connector and the IPDM E/R harness connector E8. Using multimeter to measure ECM port 3 and IPDM E/R port 42 is conduction = normal. 6) analysis of the results of integrated circuit map and measuring line: when the ignition switch is turned to ON position, ECM does not send ON (closed) signal to the throttle control motor relay, causing no battery voltage to be provided to ECM. Excluding line problems, the fault points to ECM, but ECM is generally not easy to fail. This car is also an accident vehicle. It is suspected that there are external causes causing ECM failure. 7) after the analysis of the working principle and the wiring diagram EC-229, disconnect the 15A fuse and the ECM wire harness joint, and measure the resistance between the 15A fuse output end and the ECM port 104 with the multimeter resistance gear to 0.45 Europe (by measuring the resistance of the normal car to 170 Euro), it proves that the IPDM E/R port 47 is short circuited by the IPDM E /R internal cathode, causing the excessive loss of the current. Bad ECM.. (measuring position as between red circle and arrow marking place below) 8) 8) after replacing ECM and IPDM E/R, use CONSULT-III to connect the vehicle diagnosis socket, turn the ignition switch to ON, and get the self diagnosis result of CONSULT-III to clear the original fault code, start the engine, accelerate the accelerator pedal after the car and pass the road test fault. Exclude. Maintenance summary: through this troubleshooting, let me understand the throttle control lines and work in a deeper level, the car is a number of fault points coexist in the case, the fault points and each other mutually. I think that the electrical circuit maintenance should be careful first, using the circuit diagram and the inspection procedure of the maintenance manual combined with the comprehensive analysis of the fault phenomenon, according to the principle of easy after difficulty and probability, the detection path is made, and the fault point is found by testing. So as to improve the efficiency of maintenance, avoid detours and eliminate faults as soon as possible.