Service engine soon - ZR-1 Net Registry Forums

tomtom72 · 05-08-2010

I never had a 21 but the FSM has a diagnostic path to use to check it. I guess it could cause a higher than normal idle if the ECM thinks that the blades are open and they actually are not.

The simplest way to do one check is with a VOM. KOEO, throttle closed, probe TPS with VOM at dark blue ( ckt 417 ) to read V output.

closed throttle V range = .46 to .62 volts. If it's out side the range you could try to adjust it back into range using the mounting screws. They go into slots which allows for some adjustment. I would guess if it's high & you can't get it back down then the next check I would do is on the Black wire ( ckt 452 ) that is the sensor ground. If it's open it will set a 21. Or maybe check the 452 wire first for a bad ground, then check the output V?

I hope this helps some?

Tom

05-08-2010	#2
tomtom72 Join Date: Dec 2004 Location: Jacksonville, FL USA Posts: 4,609	Re: Service engine soon I never had a 21 but the FSM has a diagnostic path to use to check it. I guess it could cause a higher than normal idle if the ECM thinks that the blades are open and they actually are not. The simplest way to do one check is with a VOM. KOEO, throttle closed, probe TPS with VOM at dark blue ( ckt 417 ) to read V output. closed throttle V range = .46 to .62 volts. If it's out side the range you could try to adjust it back into range using the mounting screws. They go into slots which allows for some adjustment. I would guess if it's high & you can't get it back down then the next check I would do is on the Black wire ( ckt 452 ) that is the sensor ground. If it's open it will set a 21. Or maybe check the 452 wire first for a bad ground, then check the output V? I hope this helps some? Tom __________________ 1990 ZR-1, Black/grey, #2233, stock. ZR-1 Net Reg Founding Member #316 & NCM member