I have been trying to track down my sputtering problem for some time now. I got a SES yesterday. Code 16 Lo –Res Failure, Code 18 Unknown and Code 22 Throttle position low. I think the throttle position low is because I took it off the clean and to make sure it was damaged. It might be off just a bit now. But I need to know what the other two codes mean. I replaced the MAP sensor the other day. Still looking into why I’m sputtering and then fine from time to time.

Thanks in advance.

 

Low res. code is ur opti

 

DTC 16 is loss of low resolution pulse from the Opti. If the engine is running, its a "stored" code, because if it was "active" the engine wouldn't run at all. Clear the PCM by pulling the "PCM BAT" fuse for 30 seconds, and see how soon the code comes back. It isn't unusual to find that as a stored code, possibly a result of the PCM having a hard time finding the low res pulse pattern on startup. If the code returns quickly, it may be a problem, but you need to check the wiring harness connections for the Opti, to insure the pins are not corroded or damaged.

DTC 18 means the PCM is seeing an electrical circuit problem on one of the injectors (but it doesn't tell you which one). Check the pink wire on each injector connector for +12V with the key on/engine off. With the harness connector off, check the resistance across each injector - should be 12-15 ohms.

DTC sets only when the TPS voltage drops below 0.20V. There is no adjustment on the TPS, and the PCM will accept any value from 0.20-0.90V as the baseline closed-throttle voltage, and prorate the throttle position percent by adding about 4V to the closed throttle reading. Since you have a scanner, check the TPS voltage.

Use Shoebox's LT1 specific code list for decoding:

http://shbox.com/1/Dtcs.htm