Question-------------------------
Followup To
Question -
We own a 1996 Dodge Caravan. It has problems stalling as you drive down the road. We have had the spark plugs, fuel filter, and 02 sensors replaced. No change. Please help. It just had a tune up and has had regular oil checkups. We don't understand. Thanks.
Answer -
Hi Tricia,
I assume that the engine restarts either immediately or soon after it stalls and doesn't require you to get a tow, correct? There is a reasonable chance that one of the sensors or actuators in the engine control system is getting quirky. It may be possible for you to ask the engine controller whether it has observed any failures in the control systems that are stored as codes in its memory. The most useful thing to do would be to try to get the fault codes that may stored in the engine controller memory to readout. Try using the ignition key: turn it "on-off-on-off-on" and leave it "on" (doing this quickly, no longer than 5 seconds). By "on" I mean just the normal position when the engine is running, not the cranking position. The 'check engine'light will remain on when you leave the key in the "on" position with the engine still not running. But then watch the 'check engine' light to begin flashing, then pause, flashing, pause, etc. Count the number of flashes before each pause and keep track of the numbers. Repeat the readout and verify the counts are correct. Then group them in pairs in the order that they came out, thus forming two digit numbers. You may notice that the pause is shorter between the digits of a given number, and longer between the numbers themselves. Then send me a 'follow-up' question telling me the results of your readout. By the way, 55 will be the last number (two groups of 5 flashes each) and that is the code for "end of readout".
I have the troubleshooting manual for several engines and we can look up the possibilities of what is wrong based upon what fault codes you show. When you write back tell me what engine you are driving.
There is also an essay on fault codes at the site:
http://www.allpar.com/fix/codes.html
which gives the meaning of the code numbers. But then you need to get specific info for what exactly might be the diagnostic tests or parts to replace to complete the repair. So I can help you with that.
I should mentiom that in '96 a new on-board diagnostic system came into effect which for some models eliminated the self-readout of codes feature. It the ignition key trick doesn't produce fault codes at all, not even a 55, then you will have to go to a good tune-up shop where they have a more sophisticated code reader in order see if there are any codes. You should be able to get a readout for under $50.
So those are some ideas for you to consider. Let me know what happens and how I might be of help.
Roland
Roland,
I just took it for another drive and the check engine light came on so I check for fault codes again. It came 12-43-55. In reading the codes on the website you shared it indicated something with coil, cylinder, or power module. Can you explain this to us? We are going on a trip this week and want to get it repaired before we go, or is it safe to drive if any of these are the problem? We sure appreciate your advice.
Tricia
AnswerWho-ha!,
Just what I thought might happen. If you will find the square plug the connects to the spark pack, and open it you will find there to be 4 connectors arranged in a square, with a little dimple on one side of the plug socket. If that dimple is on the bottom of the socket, then the connector at the upper right corner is the common side of all three spark coils, the other end of each coil on each of the other three connectors. With a digital voltmeter measure the resistance between the commom and each of the other three connectors. It should be between 0.5 and 0.6 ohms more that it reads when you just touch to tip of the voltmeter leads together. If any of the three differ from the other two that also would indicate a bad coil. Secondly, measure the resistance between each pair of spark plug wire 'towers' of the coil pack (3-6, 1-4, 2-5) and if any of them aren't in the range of 7,000 to 15,800 ohms then that too would indicate a bad coil pack. Lastly, check the 4-wire harness to the coil pack for any sign of melt through of insulation or other damage.
So there you have a shot at this problem!
Roland
