failed inspection check engine light
Thread Starter
Joined: Feb 2006
Posts: 5
failed inspection check engine light
I have a 1998 c230. In Texas they started strict smog inspection and the inspector says my check engine light doesn't come on when the car starts as it should. Is this true for mercedes?
My car has numerous electrical issues I would be surprised if the person who sold me the car tampered with the light. My instrument panel only works 10% of the time but the lights on it always work.
Also my car has a problem where it will start missing and loses alot of acceleration capability. The problem seems to appear if you decelerate then accelerate. I've learned to really baby the gas pedal and it helps some. You restart the car and then it works.
Is the check engine light supposed to come on when you turn the key? Can I test the engine light by disconnecting something that would make it illuminate? A sensor wire or something?
My car has numerous electrical issues I would be surprised if the person who sold me the car tampered with the light. My instrument panel only works 10% of the time but the lights on it always work.
Also my car has a problem where it will start missing and loses alot of acceleration capability. The problem seems to appear if you decelerate then accelerate. I've learned to really baby the gas pedal and it helps some. You restart the car and then it works.
Is the check engine light supposed to come on when you turn the key? Can I test the engine light by disconnecting something that would make it illuminate? A sensor wire or something?
Senior Member
Joined: Dec 2004
Posts: 2,410
From:
RE: failed inspection check engine light
Hi,
The CEL Check Engine Light should come on when you turn the ignition ON. It does so to ensure the bulb or LED is functioning correctly.
The light should go OFF once the engine is running.
If the light is ON it states that something in the EMS Engine Management System is threathening emmissions legislation.
Since emmissions compliance is a key point in the State or Dtp annual check the inspectors first ensure the light is working. If it is not they don't procede with the inspection.
If your light does NOT come on with the ignition then either the bulb has gone or has been tampered with eg removed. Not sure if your model has a replaceable bulb or on more recent models to prevent tampering have hard soldered LED Light Emmitting diodes which gives better reliability than a bulb.
Unknown to many individuals it is possible to turn the CEL OFF in SOFTWARE on some (USA available only engines I think) models.
If the instrument has LED and does not work this is a possible cause.
The light ILLUMINATES when the EMS sends a signal. This signal is triggerred by and held in the EMS and can be accessed with a scanner tool which is required to reset the CEL once it has come on. The EMS will display codes which will point to your obvious engine related problems.
Sound like your engine had problems and somebody discinnected the CEL so that you wouldn't notice when the car was sold.
Come back with the codes and feedback and we will see if we can help further.
Hope this helps,
Stuart
The CEL Check Engine Light should come on when you turn the ignition ON. It does so to ensure the bulb or LED is functioning correctly.
The light should go OFF once the engine is running.
If the light is ON it states that something in the EMS Engine Management System is threathening emmissions legislation.
Since emmissions compliance is a key point in the State or Dtp annual check the inspectors first ensure the light is working. If it is not they don't procede with the inspection.
If your light does NOT come on with the ignition then either the bulb has gone or has been tampered with eg removed. Not sure if your model has a replaceable bulb or on more recent models to prevent tampering have hard soldered LED Light Emmitting diodes which gives better reliability than a bulb.
Unknown to many individuals it is possible to turn the CEL OFF in SOFTWARE on some (USA available only engines I think) models.
If the instrument has LED and does not work this is a possible cause.
The light ILLUMINATES when the EMS sends a signal. This signal is triggerred by and held in the EMS and can be accessed with a scanner tool which is required to reset the CEL once it has come on. The EMS will display codes which will point to your obvious engine related problems.
Sound like your engine had problems and somebody discinnected the CEL so that you wouldn't notice when the car was sold.
Come back with the codes and feedback and we will see if we can help further.
Hope this helps,
Stuart
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