Ok, so I thought I was being helpful…my friend just bought (one week ago) a 1995 Infiniti G20T with 130,000 miles. The car is in great condition, except for the flecking/peeling gold paint (common problem with gold or silver paints?). When he bought it the car had a couple minor issues and had the “check engine” light on. After researching a bit, we figured that the possible issues causing the check engine light couldn’t be too severe, given the car’s asking price. So, he buys the car and I look up how to check the “check engine” light codes. I manage to get at the ECU and record (with the blinking red light) two codes: #34 and #105 - knock sensor and EGR + canister and control soleloid. Good news, I told him. Both of those are relatively cheap to fix. So, I close up the ECU access and ask to borrow the car to run a couple errands. Let me mention at this point that the car has been running GREAT for a week - no issues at all. So, I go to one store, shop, get back in the car, make another stop at a store, get back in the car, make a third stop at a store and as I’m parking the car appears to start to loose power - engine seems about to stall and lights fade a bit. I rev the engine and it’s fine. I (stupidly) go into the store and return to the car which now won’t start. Turning the key to the crank position produces “click click click” and nothing else. Radio and lights work, but I turn off all these in case it’s a low battery. Again - click click click.
Any ideas of what might be going on? Going to head to the store at noon and try to jump the car. Any help would be SO much appreciated. -Joe in Seattle (yes, I walked from his house to the store in the pouring Seattle rain yesterday)
Did I DO anything to cause this when I checked the ECU? Why would it suddenly have issues right after I messed around with it? Note: when checking the codes, the system appeared to reset- meaning the check engine light turned off.
Check for a low/bad battery and check the condition of the battery cables for cracked insulation/broken wires and check the battery posts and cable terminals to be sure they are tight and corrosion free. Many times simply cleaning/tightening the battery posts and terminals is all it takes to correct a no start condition.
While anything’s possible, my guess is that the seller knew he had a problem, charged up the battery in order to sell it, and you had the bad luck of driving it when the battery went dead. But if charging the battery and checking the charging system doesn’t get it back running, then maybe you did do something. Hard to tell from here.
Check the voltage of the alternator output when you get it running again. It would be a good idea to clean the battery connections also. If the alternator voltage is below 12.8 volts while the engine is running then make sure the battery warning light turns on with the ignition on. Check the fuses also.
Everyone is doing fine with the parking lot death and no-start conditions.
I’m actually dying to hear about this one: “we figured that the possible issues causing the check engine light couldn’t be too severe, given the car’s asking price.”
I’m guessing that came out wrong? Its all I can guess because it makes no sense at all. Its true that it is water under the bridge, but I found that to be the most curious bit if reasoning.
This isn’t water under the bridge, however: “two codes: #34 and #105 - knock sensor and EGR + canister and control soleloid. Good news, I told him. Both of those are relatively cheap to fix.”
What, exactly, are the fixes? Do you assume that you just replace the parts referenced by the codes? Ok. You could get lucky. Or maybe you could do some more research about what theses kinds of codes really mean. They don’t mean that parts are bad. A problem with a part is only one reason that a particular code might get set.
To answer your question, no you did not do any harm by checking the fault codes. It’s a 17 year old car and these things can be expected…Few things on this car will be cheap to fix…
The ECUs with the “twist to blink” switch have never been damaged by even the most inept DIYers that I have come behind. As long as the wiring remains connected to keep the housing grounded and nothing is forced or hammered on and no voltage is jumpered into the system they seem quite bullet proof. If all you did was pull the box out, open the viewing port and turn the switch to the code and/or O2 test position you almost certainly did not damage it. But I wasn’t there.
Lesson to learn from this (since everyone else has already answered): Do Not Buy A Car With The Check Engine Light On.
If the seller doesn’t care enough to take care of the problem before he goes out to try and convince someone to buy the car, then you know he didn’t care for the car at ALL when he wasn’t thinking about trying to sell it. This car has probably had a hard life, and your friend should be prepared to learn a lot about fixing cars if he keeps it.