2014 G550, 2000 SL500, 1995 E320 Cabriolet, 1980 TR8
Cool. I will be curious about the results. Remember, the resistor should only be energized for a few minutes during cold startups.
My guess is that the meter that reads 4.2 ohms is also the one that reads 0.6 to 0.7 shorted. General purpose meters (read, inexpensive) meters can be inconsistent with low resistance measurements because there is no "zero" function.
I'd give the 6 ohm resistor a try since you have it. The worst that could happen in that the test is inconclusive and the ECU still throws a code.
Given that it is energized for only a few minutes, is that more of an FYI on your part or are you warning me of something?Cool. I will be curious about the results. Remember, the resistor should only be energized for a few minutes during cold startups.
Not all cars. I have a 95 e320 Canadian import and it has smog pump and I occasionally get code 4.I believe the Canadian version of the M104 HFM ECU does not have a smog pump. I had one, but I sold it when I sold my Turbo Techniques setup. PM member joef (from whom I got it) and see if he has the P/N and/or a line on one.
As for the resistor, I don't know the resistance value off the top of my head, but you would need to measure the resistance of the old pump coil and then calculate what wattage would be required (W = 196/R for this application).
Sorry for late reply, been out of town for a bit.I just happened to be looking at the table of error codes and noted that code 35 for the air pump says, "Model 124,129 and 140 AIR pump switchover valve and/or electromagnetic AIR pump
clutch." There is no mention of airflow as part of this error code. Is this the code you have? If so, this makes me think that you may have an intermittent connection to the resistor or it's value is not low enough to fool the ECU.
Just a late thought. . . .
Which diagnostic pin number are you reading the code from? Do you have a California car with the Diagnostic module and the push button and LED on the diagnostic connector?Sorry for late reply, been out of town for a bit.
So, I have error code 4 (air pump inop). I verified the connections as the car warms up in its first two minutes, especially that the resistor gets hot to the touch.
I can try another resistor, maybe 4 ohm?