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I have a 97 base and it’s had intermittent issues with codes p1120 and p1220 about 2 years ago when this started I was also getting p1518 along with the p1120 and c1278 and b2723 and the u1064 left door and right door . Now after replacing TAC module it has erratic idle and throws codes p1220 and c1278 and b2723 and of course reduced power! Thinking about replacing throttle body and or app sensor. I’m at the end of my rope any input or help will be greatly appreciated!
I would chase the P1220…do you have a scan tool that can look at the TPS sensor data PID voltages or do you have a DVOM and know how to use it…if this is over your head seek out a diagnostic shop or an auto electric shop…what sets this DTC is attached below…a lab scope is the best diagnostic piece of equipment in that it can see these small voltage changes that a DVOM might miss since its refresh rate is slow…a scan tool is a little better…you can make sure the wiring connector pins aren’t spread apart.
I do know my way around cars I am a technician have been for 26 years I know how to use a voltmeter scan tool and anything else imaginable. Anyway, I’m asking for help with this problem thank you in advance for any help.
I replaced the TAC module about 1 year ago and that stopped my p1518 code Bill Curlee helped me with it even stopped by my house which was greatly appreciated. I need help I know my way around cars and vettes do it every day but I am stumped!!
I do know my way around cars I am a technician have been for 26 years I know how to use a voltmeter scan tool and anything else imaginable. Anyway, I’m asking for help with this problem thank you in advance for any help.
If you have a scan tool you can use that to look at your TPS voltage or you can use a DVOM…TPS sensors are simple potentiometers…you can look at the code setting criteria and the diagnostic “tree” below !!…if you have a scope you can use that too and would be your BEST choice …I don’t know what kind of help you need since it’s not going to be a blown fuse ??
Maybe I wasn’t clear . I get code p1120 b2723 sometimes p1220 will show and left and right door codes that all. I don’t get p1516 or anything like that. I replaced the tac module a couple years ago things got better for awhile but started getting codes again and slowly getting worse. I am a good technician and just need to know what I should check possible throttle body or app sensor
P1120 is TPS1 so you can follow the same troubleshooting process as in the 1220…TPS1 is a pull up circuit…do a pin drag test on the connector and get your hands on a scope to watch the sensor voltage as you drive around and see if the voltage drops out…also check the TPS1 signal wire at the TAC module for a bad connection..you may just have a bad TPS sensor.
97 base
