Code 201 (Emission Control)

EMISSION CONTROL
Explanation
This trouble code is stored when the emission control reaches its control limit and no other defect which effects the mixture has been detected. This may be attributed to deviations in the mixture composition (mixture too rich or too lean for longer than 10 sec).

Possible causes
- Vehicle stops due to lack of fuel (tank empty)
- Incorrect fuel pressure
- Defective or coked injector valves
- Incorrect output value from engine temperature sensor
- Secondary air in intake or exhaust tract
- Defect in tank ventilation
- Poor combustion (ignition, inlet/exhaust valves, compression etc. defective...)

NOTE: Poor engine response will occur since the Digital Motor Electronic (DME) operates with a substitute value.

Troubleshooting
- Measure CO content at exhaust manifold while observing the oxygen sensor voltage.
- Establish operating condition at the time the defect was detected.
- Proceed with displayed scan tool diagnostic instructions where applicable.