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Home >> Mercedes Benz >> 2001 >> ML430 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0100: Hot Film MAF Sensor (B2/5) >> Test Procedure

Test Procedure

  1. Hot Film Signal -  Connect DVOM between ME-SFI control module connector "E" terminals No. 47 and 48 (socket box terminals No. 103 and 104). Engine coolant temperature must be more than 158°F (70°C). Turn ignition on. Voltage should be 0.9-1.1 volts. Start engine and idle. Voltage should be 1.3-1.7 volts. With engine idling, increase engine speed. Voltage should increase with increase in engine speed. If voltage responds as indicated, test is complete. If voltage does not respond as indicated, perform remaining steps. Possible causes are wiring harness failure, air leak or defective hot film MAF sensor.
  2. 5-Volt Voltage Supply -  Turn ignition off. Disconnect hot film MAF sensor connector. Connect DVOM between ME-SFI control module connector "E" terminal No. 48 and hot film MAF sensor terminal No. 4 (Brown/Yellow wire - socket box terminals No. 104 and 4). Turn ignition on. Voltage should be 4.7-5.2 volts. If voltage is within specification, voltage supply is okay. If voltage is not within specification, possible causes are wiring harness failure or defective ME-SFI control module (N3/10). Repair as necessary.
  3. Ground Circuit -  Turn ignition off. Disconnect hot film MAF sensor connector. Connect DVOM between ME-SFI control module connector "E" terminal No. 46 and hot film MAF sensor connector terminal No. 3 (Brown wire - socket box terminals No. 102 and 3). Turn ignition on. Voltage should be 4.7-5.2 volts. If voltage is within specification, ground is okay. If voltage is not within specification, possible cause is wiring harness failure.
  4. 12-Volt Voltage Supply -  Turn ignition off. Disconnect hot film MAF sensor connector. Connect DVOM between ME-SFI control module connector "E" terminal No. 48 and hot film MAF sensor connector terminal No. 2 (Red/Blue wire - socket box terminals No. 104 and 2). Turn ignition on. Voltage should be 11-14 volts. If voltage is within specification, voltage supply is okay. If voltage is not within specification, possible causes are wiring harness failure or defective fuse or relay in fuse and relay module (K40) or (F1). Repair as necessary. On CLK class and E class, fuse and relay module (K40) is located in right rear corner of engine compartment. On ML430, fuse and relay module (F1) is located in left rear corner of engine compartment. On SL500, fuse and relay modules are located in left rear and right rear corner of engine compartment and right front corner of trunk compartment. On S class models, component location is not available.
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