Is a reflash of the ECM necessary
I have gotten a Check engine light a couple of times, and then soon after it goes off. I hae a mechanic pull the codes and it is saying that Back 1 and 2 O2 sensors are staring to fail. He suggested...
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Back on topic here...
To the OP, first thing you should do is find a new mechanic. No reason to flash the ECM, and if he's using that term as slang for just clearing the codes, then definitely skip him. Next thing I'd do is clear the codes and drive on, fix nothing for now. The 'ole oxygen sensor code is the biggest liar on modern vehicle diagnostics. I read somewhere that the actual chances of an O2 sensor failing is not good, and especially have 2 fail at the same time. Usually when you have a code for 2 O2 sensor failures, that's pointing to something else. It could be anything from mis-firing coils to cracks in vacuum lines to small exhaust leaks.
The check engine light on GM trucks of that era doesn't always mean something. Is the truck driving well? Are you getting reasonably good (or good as expected) fuel mileage? Oil pressure is good? Not overheating? Drive that joker and don't worry about it. You indicate that its throwing a soft code, which means the computer is really only detecting intermittent issues. If I'm dead wrong and it really is the O2 sensors, then fix it when you have to. They won't leave you on the side of the road.
To the OP, first thing you should do is find a new mechanic. No reason to flash the ECM, and if he's using that term as slang for just clearing the codes, then definitely skip him. Next thing I'd do is clear the codes and drive on, fix nothing for now. The 'ole oxygen sensor code is the biggest liar on modern vehicle diagnostics. I read somewhere that the actual chances of an O2 sensor failing is not good, and especially have 2 fail at the same time. Usually when you have a code for 2 O2 sensor failures, that's pointing to something else. It could be anything from mis-firing coils to cracks in vacuum lines to small exhaust leaks.
The check engine light on GM trucks of that era doesn't always mean something. Is the truck driving well? Are you getting reasonably good (or good as expected) fuel mileage? Oil pressure is good? Not overheating? Drive that joker and don't worry about it. You indicate that its throwing a soft code, which means the computer is really only detecting intermittent issues. If I'm dead wrong and it really is the O2 sensors, then fix it when you have to. They won't leave you on the side of the road.
