Complete List of Common System Faults and Troubleshooting Methods for SCR part2
Bosch airless SCR system
1,Exhaust temperature sensor malfunction
Fault phenomenon: The fault light is on, and the diagnostic tool shows that the exhaust temperature sensor is faulty.
Troubleshooting: Check the exhaust temperature sensor: Measure the resistance value of the two pins of the exhaust temperature sensor and compare the temperature resistance value table of the exhaust temperature sensor. If it exceeds the range, the exhaust temperature sensor is faulty and needs to be replaced.
Check the wiring harness: Measure if there is a 5V voltage at the end of the wiring harness. If not, check if there is a short or open circuit in the wiring harness
2. Measurement pump malfunction
Troubleshooting: Check if the return pipe of the metering pump is blocked: Remove the return pipe, start the engine, and observe if there is any return liquid. If there is no return liquid, check if the return pipe is blocked. Remove the suction tube and check if the suction port of the pump has suction force. If it is a new pump or a pump that has been stopped for a long time, water can be injected into the suction port and the pump can be operated until liquid sprays out from the return port, and check if there is any return liquid.
Check the compressed air pressure: After several cycles of liquid inlet and outlet, check if there is compressed air spraying out from the injection port. If not, please check if there is any leakage in the compressed air management or if the compressed air pressure is sufficient (600 kPa~1200 kPa). If it still cannot be ruled out, replace the metering pump for testing. If the fault is resolved, it is determined to be an internal fault in the metering pump.
