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6

The CEL trigger implementation will vary across vehicles, but here are a few for you to try out. They should not have any negative effect in the long-term on the vehicle: P010x - unplug MAF sensor P030x - unplug a spark plug wire/coil (unplugging the corresponding injector is recommended) P0420/P0430 - unplug the O2 sensor after the catalytic converter


6

@JPhi1618 answer is good. I would just add a few more, You can unplug the EGR Valve electrical connector, no harm to engine. Pull out a coil pack or coil wire.


6

Start unplugging stuff. The engine will normally run with a lot of the sensors unplugged, but the check engine light will come on quickly. Some easy to reach ones: Mass Air Flow (MAF), Oxygen sensors, sometimes the throttle position indicator (on the throttle body). If you can unplug the power to the secondary air injection pump, it will cause a fun ...


5

It is most likely that this sensor has failed. The question is why does the MIL only come on above 70mph. The answer lies not in the sensor but how and when the sensor is tested by the PCM. Every sensor (and actuator) in the engine control system is tested by the software, but not all the time. Each sensor has its own set of test entry conditions; each OEM ...


5

To add to the list, run the engine without the fuel filler cap on.


5

While the fault code that popped the MIL is tremendously useful by itself, freeze frame data offers huge help, as it allows you to see the exact conditions under which the engine decided that there is a fault. You will know at what RPM the code was popped, what the engine load was, whether the engine was warm and in closed loop mode, if it was overheating, ...


4

The P0420 and P0440 are completely unrelated (other than both being related to emissions). The P0420 is having to do with catalyst function. The P0440 having to do with EVAP system. There is no way for one code to have morphed into the other code. P0420 can appear and disappear over time due to the nature of what is being seen by the computer. If the after ...


3

I haven't been able to find any solid conclusions on the VW forums regarding the root cause for this behavior, but there are some clues as to what could be causing this from the diagnostic code. Fred Wilson's answer remains a distinct possibility but I struggle to reason with why the engine computer would choose to throw a code/MIL for a bad sensor on a ...


3

They help us home in on what might be the root cause Maybe an example would help explain why freeze frames are so useful Here is the P0300 freeze frame from that infamous Merc GLK280: +-----------------------------------------+-------------+ | Fuel System 1 status | 1 | | Fuel System 2 status | 1 ...


2

We find FF so useful that we retain it on the customers invoice in case the same code sets later. It is also very helpful when used in conjunction with a test drive on intermittent faults. It tells exactly how to duplicate the conditions under which the fault set. There are times when its limit of setting on only one code is frustrating because it is not ...


2

We can still read the code without a code reader with a key dance. Some people said the e-brake must be on in order to do this but the main problem in my case was about the key dance itself. Basically, there's 4 ignition key positions: Off Accessories Run Start When I was doing the key dance, I was doing it between position 1 and 3. However, I just ...


1

Because this issue is speed dependent, I'm almost certain that it is related to exhaust gas temperature. Paulster2 suggested checking whether the issue happens at a lower gear. However, then the load on the engine is lower, so there are less exhaust gases. It may be the case that the issue does not happen at a lower gear, therefore. But a good idea to check ...



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