Join Date: Feb 2004
Location: Vancouver, BC, Canada
UPDATE - Problem finally fixed, root cause found!
Turns out, the Input Speed Sensor wire is intermittently shorting out against ground. After poking around with a multimeter, I've determined it's the connector or wire loom near the brake booster.
Lesson learned, after $110 / 2 sensors: just because the code points to a sensor circuit, don't run out and buy them! Especially if you have a 02+ car, which the sensors rarely go out.
Overall, this was one tough problem to trace down, took me almost 1/2 a year, part of the problem is the intermittent nature - it only happens when cold. Spend hours blowing hot air at various wires and connectors with no success. Measure both sensor resistance from the PCM connect, both perfect (620 for output and 700 for input). But just for the hell of it I decided to measure them against ground, on a cold morning, and voila.
To prove it's not a fluke, here're the readings: input to ground - 0 ohms; sensor ground to ground - 620 ohms; output to ground - 1320 ohms. Does the math look familiar to the numbers above?
Both input and output sensors share a common sensor ground (NOT vehicle ground! completely isolated). This makes both sensors in series. So when input is shorted to vehicle ground, everything else follows (sensor ground and input).
I will re-splice a new run of signal wire when I have time. For a temp fix, I took apart the large connector by the brake booster, gave everything a good clean and make sure it's no longer shorted. Been perfect for 3 days now. Just throwing this out there in case other have the same problem.
2003 Police Package
2006 C6 Z06 (traitor)
2014 Ram HEMI 8 spd
It takes a Mopar to catch a Mopar
Last edited by RJ; 11-27-2012 at 12:07 AM.