2000 Cadillac DeVille, Runs Poorly Code P0102

This 2000 Cadillac Deville Came in with the complaint of running poorly and a code P0102 was present. The customer had already replaced the MAF (mass air flow) sensor and tried to replace the harness connector. Why anyone would consider this a repair is beyond me.

Looking at MAF data, the grams per second and the hertz data were at or near zero. This was even with the engine running. The picture below shows that the engine was not running but trust me the numbers were only slightly different when it was running.

Since the wires were exposed, I took advantage of that and did some quick tests. The key on voltage on the pink wire was 1.429 volts. According to the schematic the voltage should have been battery voltage with the ignition on.

The schematic also showed that the power is supplied through the IGN 1 fuse in the underhood fuse box. I am pointing to the IGN 1 fuse in the fuse box legend in the next picture. It is also marked as fuse number 11.

I am pointing to the IGN 1 fuse on the fuse box layout in the next picture.

With the key on there was power on one side of the fuse.

No power on the other side.

So, replacing the blown fuse should restore power to the pink wire at the MAF sensor.

The new fuse has power on both sides.

There is now nominal battery voltage at the pink wire connecting to the MAF sensor terminal “D”.

I installed a new harness connector by splicing in a staggered pattern and finished with a new piece of split loom to dress out the repair. The split loom along with the electrical tape that was used at the end, to fasten the loom to the wires helps stabilize and strengthen the over all repair.

Now the MAF data is active and the engine is running well enough to finish doing some other testing related to a misfire. That is an article for another day though.

In case you need to know more terminal data, I am including the following list.


Terminal “A”        Black         IAT sensor ground at PCM terminal 4 connector C2

Terminal “B”        Tan          IAT sensor signal at PCM terminal 10 connector C2

Terminal “C”        Black        MAF ground at G100

Terminal “D”        Pink         Ignition power supplied from fuse IGN 1

Terminal “E”        Yellow       MAF sensor signal at PCM terminal 42 connector C1

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