The 1994 Mercedes-Benz E320, utilizing an OBDII system, can present a variety of diagnostic trouble codes (DTCs). Understanding these codes is crucial for effective troubleshooting and repair. This document outlines the common DTCs encountered on a 1994 E320 chassis, categorized by module. A “code 4” reading indicates a faulty Mass Air Flow (MAF) sensor.
E320 1994 OBDII: Built-in Diagnostic Module 1
This module provides general engine-related fault codes:
- Code 2: Heated oxygen sensor faulty.
- Code 3: Lambda (oxygen sensor) control faulty.
- Code 4: Air injection system faulty/Hot film mass air flow sensor (MAF) with hot wire. This was the code pulled indicating a faulty MAF sensor.
- Code 5: Exhaust gas recirculation (EGR) faulty.
- Code 6: Idle speed control faulty.
- Code 7: Ignition system faulty.
- Code 8: Engine coolant temperature sensor open circuit.
- Code 9: Intake air temperature sensor open circuit.
- Code 10: Voltage at mass air sensor too high/low.
- Code 11: Engine speed (RPM) signal at engine control module (ECM) faulty.
- Code 12: Heated oxygen sensor heater circuit open or short circuit.
- … (and more codes as listed in the original post)
E320 1994 OBDII: ECU Pin 8
This pin on the ECU provides more specific engine management DTCs:
- Code 2: Engine coolant temperature sensor faulty.
- Code 3: Intake air temperature sensor faulty.
- Code 4: Hot film mass air flow sensor (MAF) faulty.
- Code 5: Closed Throttle Position (CTP) switch faulty.
- Code 8: Idle speed control (ISC) system at limit or “limp home” mode active.
- Code 9: Oxygen sensor 1 (before catalytic converter) voltage issue.
- Code 10: Oxygen sensor 2 (after catalytic converter) voltage issue.
- … (and more codes as listed in the original post)
E320 1994 OBDII: CC/ETA Pin 14 (Cruise Control/Electronic Throttle Actuator)
This pin relates to the cruise control and electronic throttle systems:
- Code 2: Fault within the EA/CC/ISC control module, related switches, or signals.
- Code 3: Right Electronic Accelerator/Cruise Control/Idle Speed Control (EA/CC/ISC) actuator (left cylinder bank) faulty.
- Code 4: Cruise control switch faulty.
- Code 5: Stop lamp switch faulty.
- … (and more codes as listed in the original post)
Conclusion
These OBDII codes provide a starting point for diagnosing issues on a 1994 E320 chassis. Remember that a code indicates a potential problem area and further diagnostics are necessary to pinpoint the exact fault. A professional scan tool capable of reading Mercedes-Benz specific codes is recommended for comprehensive diagnostics. This information, coupled with a “Code 4” diagnosis, points towards replacing the MAF sensor. Consult your vehicle’s repair manual for detailed troubleshooting procedures.
