My son was driving the 94 Z28 and SES lite came on for "a few seconds".

I scanned and looked at the code history: Code 16: Low Res Pulse...


Is this due to some dirt in the optispark? If so, can I try to blow it out through the port in the bottom? Or My MSD or coil? Just a low battery? Or just a fluke?

Hasn't happened again for 50 miles....

Worry or not?
THANKS!
Ram

 

Check the connectors in the harness wires to the Opti. There are two.... the one that plugs into the Opti and a gray one on a bracket on the passenger side of the intake manifold. Make sure the connectors are not corroded or damaged. The one on the intake manifold is generally not a problem, but the one on the Opti will often get a blue-green corrosion on it that can screw up the signals.

Next would be the possibility of something "blinding" the optical sensor. Rust from the bearing retainer is a common problem. Oil or moisture might be an issue.

Or, maybe its just a "fluke". I've seen the code pop up seemingly as a result of the PCM having a problem finding the signal on startup.... under those condtions you don't notice the light because it might still be in test mode.

Clear the code (pull the PCM BAT fuse in the panel at the drivers end of the dash for 30-seconds). See how long before it comes back. Its not unusual to find it as a "stored" code, and for that not to be an indicator of a problem.

Were there any other codes when you scanned it?

 

6 Months ago my car did the same thing, havent seen the code since then. Iam not going to worry about mine until the SES light comes on again with that code.

 

Hey Injuneer,
Thanks for the great advice. My replies in ()

Check the connectors in the harness wires to the Opti....
(EXCELLENT advice...had not heard of these simple possibilities before- everyone should do this before just replacing the SOB! will do!)

Next would be the possibility of something "blinding" the optical sensor....

(Yep, come to think of it, I have been losing coolant lately and so several times recently...I filled bled the brass screws on top of the radiator hoses....and STUPIDLY ... I did not use a towel over the waterpump/ opti area...I bet it was moisture...luckily it seems to have dried out- I will NOT screw up again! )

Or, maybe its just a "fluke". I've seen the code pop up seemingly as a result of the PCM having a problem finding the signal on startup.... under those condtions you don't notice the light because it might still be in test mode.

(Yeah, something as simple as low battery as my Haynes manual suggests, at start up or soon after with a lot of accessories on , headlights on and then the air pump comes on. (We've all seen your headlights flicker before)

Clear the code (pull the PCM BAT fuse in the panel at the drivers end of the dash for 30-seconds). See how long before it comes back. Its not unusual to find it as a "stored" code, and for that not to be an indicator of a problem.

(Yes, actually it was a stored code in trouble code history on my AutoXray...I cleared it and it has not come back yet)

Were there any other codes when you scanned it?

(NoSSIR!)

(THANKS INJUNEER, I will check both of my Camaros for corrosion and keep after it with some battery terminal spray. You've given me confidence, Peace out! )

Ram

 

Fred mentioned it's not unusual to see the code stored because if it is an "active" code, the engine would not run.

LT1t56 you're going to wait a long time for the SES. DTC16 disables the fuel pump and injectors but does NOT set an SES light. If your SES light was on, and you had a DTC16, there was some other reason the SES came on.