'95 Metro 1.3L Error code 15

Hello All,

I have a '95 Metro with the 4cyl engine and manual transmission with almost 150K miles on original engine and transmission. The check engine light came on recently and when I read the codes it came back with a code 15 (Coolant sensor circuit low voltage input, high temperature indicated). The car is not overheating. I checked the connections at the ECM and they appear to be good so I changed out the sensor (at least I hope it was the right sensor). I cleared the codes and then took a test drive. After about 10 minutes the car heated up to normal and I saw the temperature drop on the gauge (thermostat opening) at what was the normal spot. Right at that time, the check engine light came on again. Thinking that just maybe the thermostat was sticking, I replaced that also (for lack of any other ideas). Still the same problem. Does anyone have any ideas at this point? I am fresh out. Will driving with this problem cause any significant issues with the car? I assume that with the fault, I will lose a few miles per gallon but since I know that it is not overheating I am not worried about damaging the engine.

Thanks,

Shades0872

http://www.troublecodes.net/suzuki/

Coolant temp sensor or wiring.

There are three separate temperature sensors. The two on the thermostat housing run the fan and the gauge. The one that reports to the computer is mounted on the throttle body, that's the one you want.

Are you sure you didn't "capture" the flashes backwards, and you really have a code 51? Code 51 for the EGR is VERY VERY common on Metro's. If it is Code 51, it's most likely the passage plugged between EGR valve into the Intake Manifold to below the throttle body. Your check engine light comes on at this point because once the engine is at operating temperature, it goes into closed loop, and starts checking operation of various sensors.

I thought of that and checked the codes again. I am almost 99.9% positive that I am reading them correctly. When I jumper the diagnostic connector and then turn on the ignition I get one flash, a pause, and then five more flashes. and then it repeats. After checking a few connections last night and then clearing the codes I managed to drive to work without the check engine light coming on. However when driving home, it came back on. I am on my way down to the garage to bang on this thing some more. Could it be a loose ground? Where are the grounds located for this thing? The diagrams and pictures I have are not very clear at all. I have a Haynes manual that is just about worthless.

I have looked all over the throttle body and cannot locate another sensor like Woodie83 suggested. This is a mid year model and there are a lot of things that aren't quite matching up with the earlier part of the year, like the location of the ECM.

I may have given you bad information. I remember clearly that the earlier cars had three, but I just looked in my 98 FSM (yes, Haynes and Chilton's suck for this kind of thing) and it's only showing two, one for the fan and one for the PCM. When you look at the engine contols schematic it shows the ECT sensor connecting only to the PCM. When you look in the gauges schematic, it shows the ECT sensor connected only to the gauge. What's up with that? Something's wacky in the book. Sensor ground is two big ring terminals that get bolted to the intake manifold, or maybe to the block just below the intake manifold.

Well, I feel like an idiot! After reading all of the replies here, I went and checked the codes again. Turns out it is actually a code 51 not a code 15. The light flashes once when you first turn on the ignition which was throwing my count off. I sat and watched the silly thing run through the codes for about 5 minutes and caught the long pause before it starts to repeat the codes and verified that it is a 51. Good catch there metro_roy. Anyway, I am going to let the car cool tonight and will pull the EGR valve out tomorrow evening to check and clean. I will post the result after that. Thanks for all of your help and suggestions.

You may find the EGR valve is not clogged and therefore the common issue with these cars would be in play.

The EGR gasses pass from the side of the exhaust manifold, through the head, through the intake, and to the valve. This is also may or may not be the reason exhaust valves burn up in these cars.

Please check out the info on this page from TeamSwift.............
http://www.teamswift.net/viewtopic.php?t=25919

Johnny's right, the whole EGR system needs to be cleaned out, the worst of it is usually in the intake manifold passage.

After two hours of research last night, I'm going back to my original statement that the ECT is mounted near the throttle body and fed by the two little hoses that warm the throttle body. Doesn't matter for your problem now.

Love your signature, I'm a huge Dune fan.

Shades:

My present Geo is also a 95 1.3L and I had EGR problems several years ago at about 150K too. This was before I found this and some other good forums so I just followed the trouble shooting given in the factory service manual. I replaced the EGR valve out of desperation, and some other parts. I could at that time feel vacuum on one port and pressure at the other, so I presumed that the passages were not plugged. The car ran fine, so after several weeks any many more beers I just ignored the light. Then at about 175K I had to run the car for 60 miles on the Interstate at 70MPH for business. The car idled terrible when I got there. Long story short, burned an exhaust valve. While repairing the valve, I found that I couldn't blow 125 PSI air through the EGR passage into the intake manifold. It took a lot of work to snake out that crooked passage way. After I got it all together, no more code 51. I suggest you pull of the intake manifold, remove the throttle body, and get the passages really clean. I'll bet money that this is your problem. I'm as sure of this as I'm sure your dashboard is faded and your headliner is sagging.

The saga continues! Well, I finally got the time to work on this thing. Unfortuantely not enough time to pull the whole intake like metro_roy suggested. I checked out the egr system first and everything appeared to be o.k., so I went ahead and pulled the egr valve. It was almost completely plugged with carbon deposits. I cleaned out the intake manifold by shoving a bottle brush up in about 2~3 inches and then hitting it with a vacuum cleaner. I then shoved some plastic tubing up the ports and hit that with the vacuum cleaner also. Got quite a bit of junk out of it. After cleaning the egr valve and as much of the intake manifold that I could, I reassembled everything and took it for a test drive. Went about 18 miles and then the check engine light came on again. Same code of 51. I went through all of the checks again, and now it looks like the egr valve diaphram is shot since it won't hold a vacuum for longer than about 5 seconds. Guess I need a new egr valve. I plan on ordering one tomorrow from the local parts store so it will probably be in some time next week.

On a different note, metro_roy is right, the dash is fading in a lovely marble pattern, and the headliner is held up with thumbtacks.

Thanks.

My EGR valve came in and I just got done putting it on and taking it for a test drive. The problem appears to be solved. While I had the EGR valve off I went ahead and did a better job of cleaning the ports out. I didn't get too much more junk out but there was some. Hopefully I can go for another 150K before needing to do this again.

Thanks for all of your help.

Shades0872

Glad it's working for you!

If you can stall the engine at operating temperature at idle by manually opening the valve you are done.

-MechanicMatt

When I manually open the EGR valve when the engine is cold, the engine starts to stall out and then the idle gets kicked up by the ECM and it just runs rough. Tried this several times as a check after getting the new EGR valve on. The engine never actually dies from manually opening the EGR valve, but does respond the way I would expect if it was functioning normally (from what I understand). From what I have seen when the engine reaches normal operating temperature the EGR valve is opened anyway (not 100% sure of this).

Thanks again,

Shades0872

Only at medium throttle openings, EGR does not operate at idle or wide open throttle.