EGR Output Stage Malfunction
1990-2002 Mercedes-Benz SL 3.0L I6
Description
The ECU detected a malfunction in the EGR (Exhaust Gas Recirculation) valve output stage. The ECU cannot properly command the EGR valve, affecting NOx emission control.
Symptoms
- Check Engine Light
- Higher NOx emissions
- Failed emissions test
- Possible rough idle
- Slight power loss
Common Causes
- Faulty EGR valve actuator
- Carbon buildup in EGR valve
- Wiring fault to EGR valve
- ECU EGR driver circuit failure
- EGR valve stuck
Diagnostic Steps
- Test EGR valve operation with scan tool command
- Inspect EGR valve for carbon buildup
- Test EGR valve solenoid resistance
- Check wiring and connector
- Monitor EGR position feedback
Repair Notes
Clean or replace the EGR valve; repair wiring if damaged.
Related Codes
Other Powertrain Codes
- P0001Fuel Volume Regulator Control Circuit/Open
- P0002Fuel Volume Regulator Control Circuit Range/Performance
- P0003Fuel Volume Regulator Control Circuit Low
- P0004Fuel Volume Regulator Control Circuit High
- P0010Intake Camshaft Position Actuator Circuit/Open Bank 1
- P0011Intake Camshaft Position Timing Over-Advanced Bank 1
- P0012Intake Camshaft Position Timing Over-Retarded Bank 1
- P0013Exhaust Camshaft Position Actuator Circuit/Open Bank 1
- P0014Exhaust Camshaft Position Timing Over-Advanced Bank 1
- P0015Exhaust Camshaft Position Timing Over-Retarded Bank 1
P1400 on Other Vehicles
Mercedes-Benz 500SL R129
1990-2002 5.0L V8 M119
Mercedes-Benz 600SL R129
1993-2002 6.0L V12 M120
Mercedes-Benz A220 W177
2019-2024 2.0L I4 Turbo M260
Mercedes-Benz A250 W176
2013-2018 2.0L I4 Turbo M270
Mercedes-Benz A35 AMG W177
2020-2024 2.0L I4 Turbo M260
Mercedes-Benz A45 AMG W176
2014-2018 2.0L I4 Turbo M133
Mercedes-Benz A45 AMG W177
2020-2024 2.0L I4 Turbo M139
Mercedes-Benz AMG GT
2015-2024 4.0L Turbo V8
Common Questions
What does code P1400 mean on a 1990-2002 Mercedes-Benz SL?
P1400 stands for "EGR Output Stage Malfunction". The ECU detected a malfunction in the EGR (Exhaust Gas Recirculation) valve output stage. The ECU cannot properly command the EGR valve, affecting NOx emission control.
What are the symptoms of P1400 on a Mercedes-Benz SL?
Common symptoms of P1400 include: Check Engine Light, Higher NOx emissions, Failed emissions test, Possible rough idle, Slight power loss.
What causes P1400 on a 1990-2002 Mercedes-Benz SL?
Common causes of P1400 include: Faulty EGR valve actuator, Carbon buildup in EGR valve, Wiring fault to EGR valve, ECU EGR driver circuit failure, EGR valve stuck.