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Home >> Mercedes Benz >> 2001 >> ML430 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P1400: EGR Transducer (Y31/1) >> Testing Procedure
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Testing Procedure

NOTE: This test procedure is not possible on vehicles with 4-wheel drive systems.
  1. Actuation & Vacuum Control -  Connect DVOM between ME-SFI control module connector "E" terminal No. 5 (socket box terminal No. 61) and ME-SFI control module connector "A" terminal No. 2 (socket box terminal No. 2). Connect water vacuum gauge to EGR valve. Start engine and idle. Allow engine to idle until coolant temperature is more than 140°F (60°C). Voltage should be less than one volt and vacuum should be less than 10 mbar. If voltage and vacuum are within specification, go to next step. If voltage and vacuum is not within specification, possible causes are wiring harness failure, ME-SFI control module (N3/10) defective or EGR vacuum transducer (Y31/1) defective. Repair as necessary.
  2. Drive vehicle on a dynamometer at approximately 3000 RPM engine speed. Voltage should be 1-7 volts and vacuum should be 80-220 mbar. If voltage and vacuum are within specification, go to next step. If voltage and vacuum is not within specification, possible causes are wiring harness failure, ME-SFI control module (N3/10) defective or EGR vacuum transducer (Y31/1) defective. Repair as necessary.
  3. Current Consumption -  Connect ammeter between ME-SFI control module connector "A" terminal No. 3 (socket box terminal No. 3) and ME-SFI control module connector "E" terminal No. 5 (socket box terminal No. 61). Turn ignition on. Amperage should be 0.3-0.5 amps. If amperage is within specification, test is complete. If amperage and vacuum is not within specification, possible causes are wiring harness failure, ME-SFI control module (N3/10) defective or EGR vacuum transducer (Y31/1) defective. Repair as necessary.
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