Diagnostic Trouble Code (DTC HFM-SFI)

Turn ignition off. Perform pretest conditions. See PRETEST CONDITIONS under SELF-DIAGNOSTIC SYSTEM. Turn ignition on. Press push-button, located on diagnostic connector in right rear corner of engine compartment, for 2-4 seconds. See Fig 1 .
HFM-SFI control unit will begin output of fault codes by flashing LED light on diagnostic connector. See Fig 1 . If LED only flashes once, this indicates no fault codes are stored. If fault codes are stored, LED will flash indicating stored fault code.
Press push-button again for 2-4 seconds. If more fault codes are stored, LED on diagnostic connector will display next code. Continue pressing push-button for 2-4 seconds at a time until LED lights steadily indicating end of fault code display. Record all fault codes. See HFM-SFI FAULT CODE IDENTIFICATION table to identify fault code.

Fig 1: Locating Diagnostic Connector (HFM-SFI)

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

HFM-SFI FAULT CODE IDENTIFICATION

Fault Code

Malfunctioning Component/System

⁽¹⁾

Oxygen Sensor

Lambda (Air/Fuel Mixture) Control

Secondary Air Injection

EGR System

Idle Speed Control (ISC)

Ignition System Defect

Engine Coolant Temperature Sensor

Intake Air Temperature

Hot-Film Mass Airflow Sensor

Engine Speed (TN) Signal

Oxygen Sensor Heating

⁽²⁾

Wide Open Throttle (WOT) Function

Closed Throttle Position (CTP) Function

Data Transfer

Camshaft Adjustment Solenoid

Fuel Injectors Or Self-Adaptation Of Emission System At Limit

Vehicle Speed Signal

Purge Switchover Valve

Camshaft Position Sensor

Intake Manifold Absolute Pressure (Engine Running)

Flexplate Segments (Crankshaft Position Sensor)

Knock Sensors

Upshift Delay Switchover Valve

⁽²⁾

Engine Coolant Temperature Change Monitor

⁽¹⁾	No faults in system.

⁽²⁾	Not assigned.