Dtc Code 21 And 16
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Dtc Code 21 And 16
Two recent codes came up on my scanmaster DTC 21 AND DTC 16.
DTC 16 is distributor Ignition System(Low pulse) - Is that mean my opti spark is going bad?? Also DTC 21 Is a throttle position sensor which I replaced last summer. I basically want to know more about the dtc 16 code. I did a hole shot and it missed around 4k then was fine after that.
DTC 16 is distributor Ignition System(Low pulse) - Is that mean my opti spark is going bad?? Also DTC 21 Is a throttle position sensor which I replaced last summer. I basically want to know more about the dtc 16 code. I did a hole shot and it missed around 4k then was fine after that.
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Somehow.... I have the feeling I answered this same question on another forum earlier today.'
If your engine is running, DTC 16 is a "stored" code. It isn't unusual to see this stored in the PCM. I suspect the PCM sets it when it takes more than 2 revs of the engine to find the low res pulse pattern. Does not necessarily mean the Opti is going bad. Clear it and see how long it takes to come back. If it comes back regularly, first check the Opti harness connectors for corrosion or bent/damaged pins.
DTC 21 sets when TPS closed throttle voltage falls below 0.20V. Has to be between 0.20-0.90V for the PCM to set the baseline for 0% throttle position. Since you have a scanner, its easy to look at the TPS sensor and see if it is reading within spec. Voltage should increase smoothly as you open the blades, reaching about 4V higher than the closed throttle voltage at WOT.
If your engine is running, DTC 16 is a "stored" code. It isn't unusual to see this stored in the PCM. I suspect the PCM sets it when it takes more than 2 revs of the engine to find the low res pulse pattern. Does not necessarily mean the Opti is going bad. Clear it and see how long it takes to come back. If it comes back regularly, first check the Opti harness connectors for corrosion or bent/damaged pins.
DTC 21 sets when TPS closed throttle voltage falls below 0.20V. Has to be between 0.20-0.90V for the PCM to set the baseline for 0% throttle position. Since you have a scanner, its easy to look at the TPS sensor and see if it is reading within spec. Voltage should increase smoothly as you open the blades, reaching about 4V higher than the closed throttle voltage at WOT.
Thread Starter
Registered User
Joined: Mar 2004
Posts: 1,399
Somehow.... I have the feeling I answered this same question on another forum earlier today.'
If your engine is running, DTC 16 is a "stored" code. It isn't unusual to see this stored in the PCM. I suspect the PCM sets it when it takes more than 2 revs of the engine to find the low res pulse pattern. Does not necessarily mean the Opti is going bad. Clear it and see how long it takes to come back. If it comes back regularly, first check the Opti harness connectors for corrosion or bent/damaged pins.
DTC 21 sets when TPS closed throttle voltage falls below 0.20V. Has to be between 0.20-0.90V for the PCM to set the baseline for 0% throttle position. Since you have a scanner, its easy to look at the TPS sensor and see if it is reading within spec. Voltage should increase smoothly as you open the blades, reaching about 4V higher than the closed throttle voltage at WOT.
If your engine is running, DTC 16 is a "stored" code. It isn't unusual to see this stored in the PCM. I suspect the PCM sets it when it takes more than 2 revs of the engine to find the low res pulse pattern. Does not necessarily mean the Opti is going bad. Clear it and see how long it takes to come back. If it comes back regularly, first check the Opti harness connectors for corrosion or bent/damaged pins.
DTC 21 sets when TPS closed throttle voltage falls below 0.20V. Has to be between 0.20-0.90V for the PCM to set the baseline for 0% throttle position. Since you have a scanner, its easy to look at the TPS sensor and see if it is reading within spec. Voltage should increase smoothly as you open the blades, reaching about 4V higher than the closed throttle voltage at WOT.
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