Greetings, some strange happenings that have mechanic and me baffled. Car is a '99, 6 speed, all stock, no mods. Mileage is around 109K. I've had the car 8 years and put on 2-3K a year, long distance and local miles. Last year I hit rough, bumpy pavement on an interstate. Immediately all sorts of warning lights came on, variety of messages on the DIC, oil pressure and fuel gauges went to 0, but temp gauge went to 260. Radio went off but outside temp gauge stayed on. Windows would not go up or down. Pulled over, turned car off, waited maybe half hour, started up, everything normal for rest of trip (couple hundred miles), and the issue never happened again. Until Sunday. I hit a bump at maybe 5 miles an hour. Immediately got such messages as low fuel, check tire pressure, reduced engine power (but engine power was not affected), the dreaded ding ding ding, check gages, service engine soon, and the like. Kept driving about 10 miles. Turned car off, waited 20 minutes, started up, all normal, hit another bump, got the ding ding ding, etc., hit another bump and ANOTHER set of messages appeared. Monday took car to mechanic (3 miles away), all normal. With key on (but not engine) he started banging on the ECM and the fuse box in the footwell and the symptoms appeared. Further banging around eliminated the symptoms, back to normal. All fuses tight. Drove around rest of the day, all normal. Strikes me that hitting a strong bump causes something to become loose, another bump affects something else, another bump eliminates the warnings (brilliant deduction!). I have a raft of codes but only a few seem remotely relevant (?), such as B2282 and B2284, U1255, U1301, and the U1001-1254.. I get B2587 and 2592, column lock related (fix was done). No flood or water damage. Car always garaged. Any thoughts appreciated. Thanks, Larry

 

So many possibilities, but my first thought would be grounding.
You'd probably get better assistance over in the C5 Tech section.

 

start with the basics - check and clean all grounds, batt, alt, starter leads, etc.
good luck!

 

I too put my money on grounding issue. There are a bunch of threads on this topic, including where to look for specific known issues.

 

Hey, shouldn't you be posting boat stuff on OSO?

 

When you've got weird issues that feel like a poor contact, start with grounds, yes. Get to each, clean, re-torque. See if that goes away.

Otherwise it may well be a harness issue, just pins that are no longer making great contact. Take each harness out, and see if it has the proper mechanical resistance to a pin you insert, see if it grabs it properly. See if any are just blatantly hanging loose or have big gaps.

Failing that, it may be a broken solder joint on one of the PCBs of the various modules. That's more annoying. You'd basically need to take a box out, open it, inspect the PCB for cold / broken solder joints, and reflow as necessary. You'd take the occasion to - obviously - inspect for and clean corrosion, as well, if present. Annoying and laborious.

 

This has happened to me once a few years back. It has never repeated itself so I never researched it. Best wishes in finding your problem.

 

I guess I need a more incognito screen name! But I go three ways, cars/trucks, boats, and motorcycles.

 

Check your codes and write them down, then clear all codes, go for a ride and see if any one returns. Next time this problem happens, before shutting off the car, retrieve all codes while the engine is running.

This problem has been extensively documented by Bill Curlee and you can read more here. It is usually caused by bad contacts in a connector within the doors' rubber accordion and, since you mentioned that symptoms appear and disappear after hitting bumps, it's very likely what's affecting your car.

The female pins of the connector on that wire harness get deformed, causing bad contacts and isolating the door control module (rendering the windows inoperable). In addition to that, this could also cause a loss of communication/corruption in the Serial Data Bus affecting all modules linked by it (this would explain all messages you temporarily got after hitting a bump).




Check the connectors in both doors for deformed pins. If bad pins are found you would need to repair the connector, fixing the female pins so they have a positive grip, or replace it. If you want to replace the connector take a look at this post for some ideas.

If connectors are fine, then the problem could be downstream the connector up to the door control module, but usually it's bad contacts in the connector.

 

WOW !!!!!!! you folks never cease to amaze me . . . .peace