LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Mercedes Benz >> 2000 >> SL600 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Trouble Shooting - No Codes >> Symptoms >> Engine Output Is Poor >> Left Cylinder Bank O2S (Before TWC)
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Left Cylinder Bank O2S (Before TWC)

NOTE: For ME-SFI control module location and identification, see ME-SFI CONTROL MODULE CONNECTOR IDENTIFICATION  .
  1. O2 Signal -  Connect DVOM between left cylinder bank ME-SFI control module connector 1 terminals No. 40 and 41 (socket box terminals No. 40 and 41). Start engine and idle. Allow engine to idle for at least 2 minutes after engine coolant temperature reaches more than 176°F (80°C). Voltage should fluctuate by more than 0.3 volts between -0.2 volts and one volt. If voltage is okay, test is complete. If voltage is not okay, possible causes are left O2 sensor (before TWC) heater failure, wiring harness failure or defective left O2 sensor (before TWC - G3/3). To check left O2 sensor (before TWC) heater failure, go to next step.
  2. O2 Heater Actuation -  Connect DVOM between left cylinder bank ME-SFI control module connector 1 terminals No. 13 and 25 (socket box terminals No. 13 and 25). Start engine and idle. Allow engine to idle for at least 2 minutes after engine coolant temperature reaches more than 176°F (80°C). Voltage should be 11-14 volts. If voltage is within specification, go to next step. If voltage is not within specification, possible causes are wiring harness failure, O2 sensor (G3/3) failure or defective left cylinder bank ME-SFI control module (N3/11).
  3. O2 Heater Current Consumption -  Turn ignition off. Connect ammeter between left cylinder bank ME-SFI control module connector 1 terminals No. 26 and 13 (socket box terminals No. 26 and 13). Turn ignition on. Ammeter should indicate 0.6-3.4 amps. If amperage is within specification, test is complete. If amperage is not within specification, possible causes are wiring harness failure, O2 sensor (G3/3) failure or defective left cylinder bank ME-SFI control module (N3/11). Repair as necessary.
scientia non olet · About LEMON Manuals