Fixed check engine trouble code but light with same code comes on

sounds like vanos

Code 155 is for a problem with the heater circuit in the O2 sensor for bank two. Bank two is on the side with cylinder number two.
Usually the sensor is faulty, but the heater circuit would need to be checked to be sure. The sensor has a built-in heater to get it hot quickly after starting the engine.

Try disconnecting battery negitive battery terminal for 1min 30secs with ignition in the on position.If this fails to work a code reader is required to reset computer.... hope this helps!!

trottle position sensor is on the trottle body opposite the throttle cable

P0340 OBD-II Trouble Code - Camshaft Position Sensor Circuit Malfunction

This indicates that a problem was detected in the camshaft position sensor circuit. Since it says circuit, that means the problem could lie in any part of the circuit - the sensor itself, the wiring, or the PCM. Don't just replace the CPS (camshaft position sensor) and think that will definitely fix it.

Symptoms can include:
* Hard starting or no start
* Rough running / misfiring
* Loss of engine power

Causes: A code P0340 could mean one or more of the following has happened:
* a wire or connector in the circuit could be grounded/shorted/broken
* the camshaft position sensor may have failed
* the PCM may have failed
* there exists an open circuit
* the crankshaft position sensor may have failed

Possible Solutions: With a P0340 OBD-II trouble code, diagnosis can be tricky at times. Here are some things to try:
* Visually inspect all the wiring and connectors in the circuit
* Check for continuity in the circuit wiring
* Check the operation (voltage) of the camshaft position sensor
* Replace the camshaft position sensor as required
* Check the crankshaft position circuit as well
* Replace circuit wiring and/or connectors as required
* Diagnose/replace the PCM as required



P0133 OBD-II Trouble Code - Oxygen Sensor Circuit Slow Response (Bank1, Sensor1)

This involves the front oxygen sensor on Bank 1. This code indicates the engine air fuel ratio is not being adjusted by the oxygen sensor signal or the ECM as expected to do so, or not adjusted as often as expected to do so once the engine is warmed or under normal engine use.

Symptoms: You will likely not notice any drivability problems, although there may be symptoms.

Causes: A code P0133 may mean that one or more of the following has happened:
* The oxygen sensor is faulty
* The wiring to the sensor is broken / frayed
* There is an exhaust leak

Possible Solutions: The simplest thing to do is to reset the code and see if it comes back.
If the code comes back, the problem is more than likely the front Bank 1 oxygen sensor. You will likely wind up replacing it but you should also consider these possible solutions:
* Check and fix any exhaust leaks
* Check for wiring problems (shorted, frayed wires)
* Check the frequency and amplitude of the oxygen sensor (advanced)
* Check for a deteriorating / contaminated oxygen sensor, replace if necessary
* Check for inlet air leaks
* Check the MAF sensor for proper operation


Hope this helps (remember to rate this answer).

what you could start with is checking to see what trouble codes are being logged for this vehicle...if the engine light stays on, it means the ecu is registering a fault......by the means of a trouble code...now the trouble code doesnt tell you how to fix it, but it does give you the direction to go down...judst wondering if you have tried to obtain the trouble codes

Tom - that is your check engine light. Seems odd that is is intermittent when coming on. Usually they stay continually lit until checked/problem repaired and the code removed from your computer by a qualified service technician. Regardless, you need to get your car in for service.

Does the Check Engine light come ON when this happens? Whenever the "Check Engine" light comes on, there is always a DTC (Diagnostic Trouble Code) stored in the ECM (Engine Control Module). You'll need an OBDII (On-Board-Diagnostics) scanner to retrieve any codes recorded/set in ECM. Once you do this and let us know what, if any codes are set, then we can go from there.
There are just too many possible causes for the problem you describe. Example: Sensors like the Mass Air Flow (MAF), Throttle Position Sensor (TPS), Manifold Absolute Pressure (MAP) sensor, Crank Position Sensor (CKP), Engine Coolant Temperature (ECT) Sensor, Intake Air Temperature (IAT) sensor, vacuum leaks, intake air hose leak, Wiring & connectors, clogged intake air filter, bad/contaminated fuel, malfunctioning injectors, poor ignition/spark or spark plugs or wires, Major Engine Mechanical problems, Out of Time, etc. etc. etc.

The are many things that can cause your "check engine" light to stay on. One possibility is that although you have fixed the trouble code for your crankshaft position sensor, the code has not been erased from the computer's memory. Another possibility is that you have another issue going on that is causing a new trouble code to come up. You're going to need to have your car hooked up to a ODB-2 engine code reader to see what the issue is. These code readers are available for purchase at any auto parts store. In addition, many of your local auto parts stores will check trouble codes as a free service to customer. If not, many parts retailers offer the option to rent one of these code readers. Which ever way you decide to go, run a full engine/emissions trouble code check. If the only code that comes up is the code that came up previous to fixing your positioning sensor, then all you need to do is erase the trouble code from the computer's memory. (Most code readers have the option to erase trouble codes, but if you're going to rent or buy one, I would suggest that you check to make sure that the code reader that you're getting is capable of erasing trouble codes as some code readers only indicate the codes and will not remove them from your computer's memory.) If your trouble code scan reveals other codes, then you'll have to fix and erase them as they arise.

FYI- In my experience, I've noticed that 95% of the time that a check engine light/trouble code arises that it is usually an emissions problem (oxygen sensors, mass air-flow units, MAP sensors, etc.). However, General Motors products are notorious for getting trouble codes for having loose battery/ground connections and for having worn-out fuel caps. With any GM vehicle, I always check these two things first to try to save me from having to look further than I need to.

Hope this helps! I'm sure once you've scanned your cars computer and erased any existing trouble codes, that you'll stop being annoyed by your check engine light, as I know how bothersome it can be. Have a great day!