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Home >> Mercedes Benz >> 2002 >> ML320 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0202: CYLINDER 2 INJECTOR (Y26y2) >> Testing Procedure

Testing Procedure

  1. Actuation & Injection Time -  Connect oscilloscope between ME-SFI control module connector "E" terminal No. 1 (socket box terminal No. 57) and ME-SFI control module connector "A" terminal No. 2 (socket box terminal No. 2). Observe oscilloscope. Start engine. When coolant temperature is approximately 68°F (20°C), injection time should be approximately 8 milliseconds. With engine idling and engine coolant temperature approximately 176°F (80°C), injection time should be approximately 3-5 milliseconds. See SIGNAL PATTERN IDENTIFICATION . When throttle is blipped, injection time should be approximately 14 milliseconds. See SIGNAL PATTERN IDENTIFICATION . If injection times are okay, go to next step. If injection times are not okay, possible causes are wiring harness failure, injector failure, defective ME-SFI control module (N3/10), Engine Coolant Temperature (ECT - B11/4) failure, Intake Air Temperature (IAT) sensor (located in hot film MAF sensor - B2/5) or left O2 sensor (before TWC - G3/3) or right O2 sensor (before TWC - G3/4) failure. Repair as necessary.
  2. Resistance -  Turn ignition off. Connect DVOM between ME-SFI control module connector "E" terminal No. 1 (socket box terminal No. 57) and ME-SFI control module connector "A" terminal No. 2 (socket box terminal No. 2). Resistance should be 14-18 ohms. If resistance is within specification, test is complete. If resistance is not within specification, possible causes are wiring harness failure or injector failure. Repair as necessary.
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