Would you mind taking a look at this MAF sensor problem and giving me some help on it?

Symptoms: car will always start, but has very little power and stalls after a few blocks.

ODB II Code: P0 102 - Mass Air Flow Sensor (MAF) signal is low.

Troubleshooting so far:

1) Air Filter case and hose checked for physical damage and obvious leaks. (Passes)

With the MAF Connector disconnected:

2) MAF Connector's Pin#3 has +Battery voltage on it when ignition is on. (Passes)

3) Turn ignition off for 2 minutes, resistance between MAF Connector's Pin#4 and Ground is 9.8K ohms, AllDataDIY says should be approximately 9K to 11K ohms. (Passes)

With the MAF Connector re-connected:

4) Turn ignition on (engine not running), voltage between Pin#3 and Pin#4 moves between 0.08 and 0.1 volts. AllDataDIY says should be between approximately 0.1 and 0.2 volts.

It seems like Test 4 above has failed, although only by a tiny bit. A reman MAF sensor is $130 at NAPA, so I'm kind of reluctant to buy one unless I'm more certain that it is the problem.

Here are my questions:

#1 Would a voltage of 0.08 Volts between Pin#3 and Pin#4 be low enough to trip the computer's "low signal" threshold?

#2 Is there any cleaning or adjustment/calibration that can be done to the MAF sensor?

#3 I'd like to make a short 6-inch cable that I could use to connect my meter in-line with the MAF connector. Does anyone know where I can buy a short male-to-female cable? Also, what is the name for this type of connector?

Any and all advice is very much appreciated!!

Dave

 

I bought a new Bosch MAF sensor and installed it, the S70 is running fine again. I thought I'd pass on a couple things I learned, and also correct an error in my post above.

First, the error. I wrote:
Sorry, brain jam. I wrote the wrong Pin number: the output voltage of the MAF sensor appears on Pins #2 and #4. Pin#3 is the +12 Volt supply wire that powers the MAF sensor.

Here's the description of all 4 pins on the MAF connector:
Pin #1 - Ground
Pin #2 - Output Signal, negative
Pin #3 - 12 Volt power to sensor
Pin #4 - Output Signal, positive

In the 1998 S70 (both the 2.4 liter and the 2.3 liter) the Bosch part number for the MAF sensor is: 0 280 217 107. Bosch's technical spec sheet is available here: http://modshack.info/images/sensors_airmass.pdf

The spec sheet notes that the maximum sustained temperature the sensor will tolerate is only 110 degrees C (230 Fahrenheit). If you suspect a faulty MAF sensor, you may want to check the inlet diverter valve on the air box. Mine was broken: if it's constantly passing air into the air box that has been heated by the exhaust manifold (the pre-heat air normally used for cold starts) then you not only being robbed of horsepower, but it can be hot enough to kill your MAF sensor dead.

One last thing: this MAF sensor, like many modern ones, is of the "hot film" variety rather than the "hot wire" type. Less contamination occurs on the hot film type, in fact, there is no burn-off circuit designed into the hot film device - apparently it stays clean enough not to need it. My point is that there may be little or no success in using the MAF spray cleaning fluids to clean the hot film types. Mine had 130K miles on it, and it was clean as a whistle. An exception to this might be if you're running an oil-soaked air filter. I could see how if there was too much oil on the filter and it was blowing by, the MAF sensor could become oily and accumulate dirt over time.

I hope this is useful information.

Dave

 

After you described your symptoms, I'm certain I have this exact problem. I'm saving up for a MAF now. Thank you so much man, this thread has been extremely helpful. One thing,

Just wondering if I could get a bit more guidance on the location of the valve. Thanks