1997 Dodge Stratus

I drew up a picture of the plugs. That's easier than trying to describe the pin locations. Pin 10 is black / tan, pin 43 is black / light blue, and pin 50 is another black / tan.

Note that pin 43 doesn't GO to ground. It is the common ground return for a number of the sensors. The circuit goes to ground after passing through some circuitry in the computer. That's part of its strategy in figuring out which fault codes to set. You should find very close to 0.2 volts on that wire.

You can measure the continuity on the two black / tan wires but a much better test is to measure for voltage when the ignition switch is turned on. The undesired resistance in a bad ground wire can be way too small to measure accurately but the current flow through that resistance will cause a voltage drop that is easy to measure.

I'm surprised there's only two ground wires instead of four. One of them will be for small current sensors and the other one will be for high current stuff like injectors and ignition coils. They are separate so that any small voltage drops produced on the high-current wire, such as the current spikes when injectors fire, won't interfere with the sensor signals. They can get away with having a few tenths of a volt drop when injectors and coils fire, but those few tenths of a volt would greatly change the sensor readings if they shared the same ground wire.

When you are not cranking the engine, the injectors, coils, and ASD relay will not have any current flowing so there won't be very much in those ground wires either. The most current flow can be expected when the ASD relay is supposed to turn on for that first one second. That's when you're going to have to watch the voltmeter closely. Look for a jump in voltage on the meter's lowest scale just as a helper turns on the ignition switch. Digital meters take a reading, think about it, then display it for a fraction of a second while it takes the next reading. It's possible for it to not react fast enough to catch a momentary jump in voltage, so you might want to try it a few times.

I suspect for this condition, if a ground wire was the problem, you can expect to see a pretty high voltage. If you see a few hundredths of a volt and only for an instant, I doubt that would cause the problem we're having.

If there is no excessive voltage on those ground wires, I would have to agree it sounds like the computer is the problem. Check for corrosion in the connector pins, then I guess it's time to try a different one.

Hi Kingshorses. Please start a new question for a couple of reasons. First, we get credit for each new question we work on, but there's two other concerns. If other people do a search, they might have the exact same problem you are but it won't come up in the search unless it's exactly the same as Timwag's. That can prevent other visitors from finding a quick answer. Most importantly, only I get an automated e-mail directing me back to this thread when any reply is posted. None of the other experts will see your question, and if they know the answer, they won't get the chance to respond. You're stuck with just me here.

That said, the web site started having problems tonight with not finding the page after we post replies to new questions, but it does seem to be working for these older and on-going conversations, so I'll see if I can get you started here. Which fuse blew and when? While driving? During a jump-start? Are those wires you mentioned in the Engine Computer's plug? What are the symptoms now? Does the engine start and run? A number of people have reported finding the wiring harness to the oxygen sensors have fallen down onto hot exhaust parts and grounded out when the insulation melts. That will intermittently blow the fuse feeding the automatic shutdown (ASD) relay. To quickly test that circuit, monitor the voltage on the dark green / orange wire to the ignition coil pack, any injector, or either small wire on the back of the alternator. The wire color might have changed so just look at which wire is the same color on every injector and the coil pack. A test light works best. Many digital voltmeters take too long to respond so you could miss the following. You should see 12 volts on that wire for only one second after turning on the ignition switch. If you do, the ASD relay and fuse are okay and the Engine Computer has control of the relay. Next, that voltage must come back during engine rotation, (cranking or running). If it does not, suspect the camshaft position sensor first, then the crankshaft position sensor. The pulses from them tells the computer the engine is rotating and it's okay to turn on the fuel pump, coil(s), injectors, alternator field, and oxygen sensor heaters.

The Engine Computer is not involved with the heater fan. If it only runs on the highest speed, I would suspect the motor is tight and drawing too much current, and it burned the thermal fuse open in the resistor assembly. As I recall, the entire resistor assembly is bypassed on the highest speed.