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12.8 Unsteady Idle Speed during Warming up Process
Yes Remove the failure displayed 1 Put the ignition switch to “ON”. Use a failure diagnostic tester to check if any failure information record exists. No Next step Yes Next step 2 Check the air cleaner and look if it is open. No Replace Yes Next step 3 After starting successfully, check if air intake consumption of the engine at idle speed is around 300Kg/h (remember to check if cylinder pressure is normal). No Eliminate the leakage failure of air intake system Yes Next step 4 Turn on ignition switch, connect an adaptor between ECU and harness, and then check if the voltage between 17# and 42# pins of ECU, between 39# and 17# pins of ECU (signal output terminal of intake air temperature sensor and coolant temperature sensor) as well as 64#, 65#, 66#, 67# pins of ECU (for control of DC motor) is normal. No Overhaul Yes Next step 5 Before finish of warming up of engine, pull out the joint on electronic throttle body and observe if engine revolution will change. No Check the electric throttle body Yes Next step 6 Check if the coolant temperature sensor is working correctly. No Replace Yes Replace ECU 7 Let engine run at idle speed, after coolant temperature reaches normal value, then use a special short diagnostic tester to check if ignition advance angle is normal. No Check the ignition timing mechanism
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